Cuadernos avicolas
Transcription
Cuadernos avicolas
Cassava in Poultry Nutrition Julián Buitrago Arbeláez Jorge Luis Gil Llanos Bernardo Ospina Patiño Latin American and Caribbean Consortium to Support Cassava Research and Development, CLAYUCA 1 Cuadernos Avícolas No. 14 Julián Buitrago Arbeláez (jabuitrago@telesat.com.co) Jorge Luis Gil Llanos (j.l.gil@cgiar.org) Bernardo Ospina Patiño (b.ospina@cgiar.org) Latin American and Caribbean Consortium to Support Cassava Research and Development CLAYUCA A.A. 6713, Cali, Colombia Telefax: (57-2) 445 01 59 Web: http://www.clayuca.org Original version in spanish Translated into english by CLAYUCA Editing - Spanish version: Elizabeth Meek Muñoz Hugo Aldana Navarrete Editing - English version: Bernardo Ospina Patiño Julián Buitrago Arbeláez Design and Layout (Spanish version): Cristina Galindo Roldán (English version): Nidia Betancourth Suárez Photo Credits: CLAYUCA Hugo Aldana Navarrete Printing (Spanish version): Papel House Group (English version): International Center for Tropical Agriculture, CIAT Cali, Colombia. August, 2002 This document has been translated into English language with support from the Southern African Roots Research Network (SARRNET) 2 Cassava in Poultry Nutrition CONTENTS Preface .................................................................................................................................... 4 Acknowledgements ................................................................................................................. 5 Introduction ............................................................................................................................. 6 Agroalimentary developments based on cassava .................................................................... 7 Agronomic considerations for industrial crops ..................................................................... 8 Mechanization in commercial cultivations schemes ............................................................. 9 Management and industrial post-harvest processing .......................................................... 13 Cassava byproducts with potential to be included in poultry feeding ................................. 20 Nutritional contents of the main products derived from the cassava crop ......................... 21 Variation in the nutritional quality of cassava roots and cassava foliage flour................... 23 Inclusion levels of cassava foliage and cassava roots flour in poultry diets ...................... 26 Complementarity of cassava flour and integral soybeans in feeding programs for poultry .................................................................................................................................28 Broiler feeding ..................................................................................................................... 30 Layers feeding ...................................................................................................................... 34 Results of field experiences ................................................................................................ 36 Conclusions .......................................................................................................................... 41 References ........................................................................................................................... 43 Appendix: Some manufacturers of cassava production and processing equipments ........................... 44 3 Cuadernos Avícolas No. 14 PREFACE e are convinced at FENAVI that in tropical countries we need to find what tropical nature has to offer, products, by-products or product associations that allow us to meet, in a competitive form, the proteins and energy required by poultry. This competitiveness has to be based in achieving efficiencies and low costs similar to those obtained in temperate countries. W In our Occidental Hemisphere, countries like Brazil, and in the Oriental Hemisphere, Thailand, show significant improvements in the tropical production of raw materials and subsequently in the poultry production. We need to learn from them the action and the aspiration to produce competitively under the maximum possible tropical conditions. In an extraordinary agronomic synthesis, Dr. Julian Buitrago and his collaborators are proposing the readers of this Cuaderno Avícola No. 14, the audacious use of cassava in poultry feeding, under the premise of “tropicalización of the poultry industry”. We are conscious that the ideas of Dr. Buitrago, in particular, generate some resistance among the experts and cassava users for poultry feeding. We are conscious that his thesis are as dared to break paradigms pre-established long time ago among us. We are conscious as well that only the audacity in this field, the essay, the proof and the mistake, as are here discussed, can give future space for further development of our second potential resource in the tropical zone for the technological offer in poultry feeding: the cassava crop. It is in the reader’s hands the judicious valuation of the thesis presented and the scope of the work that this document popularizes among the agents involved in the poultry chain. With our expectation of continuing with strong steps in the challenge of tropicalization of the poultry industry, we invite you to read this document. DIEGO MIGUEL SIERRA BOTERO Executive President-FENAVI 4 Cassava in Poultry Nutrition ACKNOWLEDGEMENTS he development of this study has required the collaboration of several persons and institutions. In general, we found great interest and enthusiasm among the people we contacted to obtain information, to backup field labor or to collect and analyze the results. T Certain that it is impossible to mention all the persons and institutions that participated in the different phases of the project, we have listed the names of the institutions where the most important field work took place and those who were most actively involved with the preparation and publication of the present document: ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! International Center for Tropical Agriculture, CIAT Federación Nacional de Avicultores, FENAVI Latin American and Caribbean Consortium to Support Cassava Research and Development-CLAYUCA Universidad Nacional de Colombia American Soybean Association, ASA Corporación Colombia Internacional, CCI Ministerio de Agricultura y Desarrollo Rural, MADR Instituto Colombiano Agropecuario, ICA Concentrados del Norte Nutrilisto Avités Nutribal Pollos Carioca Avícola Santa Anita Avicauca-Agrovélez Avícola Tuluá Avícola Santa Rita Industrias Armare Procesos Agroindustriales Industrias Protón We are very grateful with these institutions and with the rest of collaborators in the other phases of the work. 5 Cuadernos Avícolas No. 14 INTRODUCTION he following publication consolidates the information about a series of efforts done by several institutions and persons that have participated in the different phases of the process of production, processing and use of cassava crop, with the purpose of obtaining an important nutritional alternative to the livestock sector, in general, and the poultry, sector in particular. Research activities conducted and promoted by CIAT, FENAVI, CLAYUCA, ICA and the MADR, are the basis for the majority of the results analyzed in this paper. T Two big issues constitute the basic argument to consider cassava as a strategic input, of great potential, in the future plans for animal feeding in tropical regions: - The agronomic, cultural and environmental conditions in many tropical regions, allow a great potential for the development of large cultivated areas with industrial cassava, with high yielding varieties in dry matter and energy, that can be used in animal feeding guaranteeing at the same time the validity of the postulates of agricultural competitiveness and sustainability. - The demand for balanced feeds and raw materials for its preparation is increasing permanently as a result of the rising demand for meat products, eggs and milk in most of the developing regions. Agriculture in these areas hardly contributes to overcome the deficit in energetic and protein sources that can compete with the imported cereals for the fabrication of the required animal balanced feeds. Considering the nutritional facts of cassava flour from roots and foliage, it is possible to consider its utilization as a partial or complete substitute of the cereals used in the production of animal feed rations for poultry and broilers. By introducing the nutritional adjustments needed in the feed rations that contain cassava roots and cassava leaves flour, animal performance can be perfectly comparable with that obtained using balanced feeds based on cereals. Considering the importance of this topic, the present document analyzes, in a very general form, various important aspects in the fields of industrialization and processing and, in a more detailed way, the animal nutrition concepts applicable to the poultry industry. 6 Cassava in Poultry Nutrition AGROALIMENTARY DEVELOPMENTS BASED ON CASSAVA T he cassava crop can be oriented towards various applications in the fields of feeding and industrialization. Humans generally consume cassava in its fresh form but the roots can also be used in different post harvest processes to elaborate products with added value or to obtain other agroindustrial inputs of great demand in the internal and external markets (starches, glues, sodium glutamate, dextrines, alcohol, modified starches, etc.). When the possibility offered by the cassava crop to be used in animal feeding is analyzed, it is important to consider that, besides roots, the aerial part or foliage represents an element of a great nutritional potential as a source of protein and natural pigments. Figure 1 presents a general scheme in which the different routes of utilization of the cassava crop, with greater emphasis in those oriented to animal feeding, are illustrated. Despite the fact that the objective of the present publication is focused towards the use of cassava in animal feeding, it is necessary to recognize that any industrial successful development in production and marketing of cassava should be based in complementary criteria to the utilization of the different products that can be generated in the transformation chain: a part of the fresh cassava roots, with the best culinary quality can be destined to direct human consumption where normally the best prices are obtained; the other part can be included in the fresh products market, with primary processing, such us frozen cassava chips or paraffin coated cassava roots. Other more complete processes that can be done are the production of cassava croquettes enriched with vegetable or animal proteins. When the roots are not suitable for human consumption, or when this market is not attractive because of low prices or little demand, a good possibility is the elaboration of products for industrial use (starches, dextrines, modified starches, etc.), or the production of cassava flour to penetrate the big animal feeding market. The adequate balance between these potential markets for cassava constitutes the main strength for the development of industrial production schemes to take advantage, in an efficient way, of the differential advantages that the cassava crop has to offer in regions where other agricultural crops can hardly prosper. 7 Cuadernos Avícolas No. 14 Figure 1. General scheme for the processing and utilization of cassava products and by-products. Fresh cassava roots Human consumption Industry starch glue modified starch Animal feeding Fresh roots Fresh cassava leaves Natural or artificial dehydration Dried roots for animal feeding By-products for animal feeding Dried leaves for animal feeding Ensiled roots Animal feeding AGRONOMIC CONSIDERATIONS FOR INDUSTRIAL CROPS There is a lot of information available about the agronomic practices recommended for the multiple uses of cassava in human consumption. There are also recommendations about varieties and quality characteristics for cooking applications. The objective of obtaining high yields of usable dry matter (digestible metabolizable energy) and optimizing other productivity parameters, with less emphasis on cooking characteristics (color, flavor, texture), has facilitated the development of varieties with 8 high yields per hectare of roots or foliage, and with a high potential for the animal feed industry. Although high yielding varieties can contain a high level of cianogenic acid, that anti-nutritional principle can be controlled by means of an adequate processing, which eliminates any possibility of affecting the animal’s behavior. When the introduction of high yielding varieties is combined with appropriate cultural practices, there is always the possibility to obtain high yields in terms of products for use in animal feeding. Under conditions of commercial cultivation it is possible to obtain production levels of 25 to Cassava in Poultry Nutrition 40 tons of fresh roots (9.5 to 15 tons of dry roots) and between 5 to 10 tons of fresh foliage (1 to 2 tons of dry foliage) per hectare. This productivity levels are almost impossible to obtain in tropical environments with other agricultural crops of direct application in animal feeding. MECHANIZATION IN COMMERCIAL CULTIVATION SCHEMES The approach of incorporating cassava production as an important alternative in the elaboration of animal balanced feeds involves, as much as possible, the implementation of modern production techniques, in the different stages of the production chain: cultivation, harvesting, transportation, processing, storage and utilization. Besides the incorporation of high yielding varieties, the concept of industrial production includes the planting in production units that are profitable and adequate for the introduction of mechanization practices both in the cultivation and in the processing of the final products. Mechanization (with the subsequent reduction in production costs) can be applied specially in three phases of the process: during the planting, during the harvesting of roots and foliage and during the post harvest process to obtain cassava roots and foliage flour. Some of the most important aspects of the mechanization process for cassava planting and harvest operations are: Mechanized planting In recent years, important progress has been made in the development and adaptation of efficient equipment for mechanized planting of cassava, especially through the application of technology developed in Brazil. Although Figure 2. Aspects of Industrial Production Schemes. 9 Cuadernos Avícolas No. 14 Figure 3. Equipment for mechanized planting of cassava (two and three rows) the incorporation of these equipments in cassava industrial cultivation schemes is not yet a common practice, the results obtained during the demonstrations made in different regions, are giving a good evidence of the potential of this practice to reduce costs and increase the efficiency and profitability of the crop. For example, a Brazilian company named Planticenter has developed prototypes for mechanized planting that allow the planting of 7 to 8 hectares per day with the 2 row model. There are also some models available for planting 3 rows simultaneously (Figure 3). The principal characteristics of these equipments include: • Hydraulic lifting • Seeds cutting through circular sieves 10 • • • • • • acccionated by the power device of the tractor Variable planting distances (55 to 90 cmts) Variable distances between rows (90 to 120 cmts) Seeds of irregular size are eliminated Two devices for mechanized application of fertilizer, with capacity of 70 kg each one Ridging soil device based on twin concave disks Control device for the depth of the planting Mechanized harvesting of cassava roots For the harvesting of cassava roots, there are also equipments available, perfectly tested under commercial conditions that allow reduction in the labor required per Cassava in Poultry Nutrition hectare and the harvesting costs. The principal characteristics of these equipments include: • Attachment to the tractor through the power device • Cutting disk for the weeds and residues • Device for softening the soil on both sides of the harvested row • Harvesting device with nail in the rigid system and spring device in the flexible system Table 1 presents the information related to the performance of the harvesting operation per person, when the two methods are compared, the traditional manual harvesting system with the methods of mechanized harvesting, using the 2 prototypes mentioned previously. The yields are based in a planting density of 10.000 plants per hectare and a yield of 12.5 tons of roots per hectare (Figure 4). Figure 4. Prototypes for cassava roots harvesting. (Rigid and flexible). a) Rigid model b) Flexible model 11 Cuadernos Avícolas No. 14 Table 1. Comparison between yields per person with the manual and mechanical harvesting systems. Harvesting method Plants harvested Number of workers Hours worked Tons/man per day Manual 60 1 2.5 0.240 Rigid model 60 1 0.5 1.195 Flexible model 60 1 0.6 0.991 Mechanized harvesting of cassava foliage The economic feasibility in the implementation of intensive cassava foliage production systems, depends to a laryer extent in the possibility of maintaining the labour costs as low as possible, especially in relation to the harvesting operations. Important developments have also been obtained in the development and adaptation of equipment to collect the foliage of the cassava crop. One option is to use a machine operated by one person to cut the foliage which is later chopped using a mechanical cutter. (Figure 5) Recently, CLAYUCA has been working with a Brazilian company to develop one prototype. The equipment works attached to the tractor and makes the cut at the superior third of the plant, using a device of 4 disks in a row. This equipment is useful in large-scale plantation although it has the inconvenience that the harvested Figure 5. Manual harvester and cutter of cassava foliage. Figure 6. Mechanical harvesting of cassava leaves and stem. 12 Cassava in Poultry Nutrition Figure 7. Mechanical harvesting of cassava leaves and stem. The cassava foliage is cut, chopped and deposited a track. foliage remains above the soil and has to be collected (Figure 6). input for animal feeding in the form of flour, chips or pellets. Other recent development in this field has been the development of a prototype that can be used to harvest the leaves of the cassava plant (new and old plants), cut them into small pieces and send them into a truck or a collecting device (Figure 7). MANAGEMENT AND INDUSTRIAL POST-HARVEST PROCESSING The basic aspect in every industrial type scheme refers to the implementation of mechanized practices, fast and with the maximum efficiency, in order to guarantee an important reduction in production costs per ton of the final product. Raw materials usually consist of products with high volume and humidity (roots and foliage), which demand the introduction of low cost transportation systems, bulk handling and continuous type processes. This section discusses some aspects related to transportation, processing and management of the harvested roots and foliage, until its final presentation as an After the roots and foliage have been harvested it is important to transport them to the processing, unit as quick as possible, using high efficiency transportation 13 Cuadernos Avícolas No. 14 methods (trucks, or vehicles conditioned for the mobilization of bulky products). One of the most important considerations during the planning process of the industrial production system refers to the convenience of locating the point of collection and processing of the roots as near as possible to the crop production areas. It is necessary to take into account that when roots and foliage are transported in its fresh form, these products have more around 65% of humidity, a factor that has a severe impact on transportation and industrial management costs. The information presented in this section refers only to the methods used currently to obtain cassava roots and foliage flour that can be used as raw material for poultry diets. The most important steps include the processes of cleaning, chipping, dehydration, milling and/or pelletizing. Although there is plenty of information available about these processes, in separated form, the development of continuous processing systems, in large scale, integrated and with great efficiency is still missing, especially in relation with the dehydration of the raw material. Principal methods for dehydration of cassava roots and foliage Although numerous dehydration systems have been developed for other agricultural crops, in the case of cassava, very little 14 experiences are known related to important industrial experiences different than the dehydration methods through solar energy or mechanical methods of forced heat based on electric power, steam or fossil fuels (gas, ACPM, etc.). Considering the high humidity percentage that needs to be extracted from the cassava roots or foliage, it is very important to select a dehydration method that can operate with a minimum processing cost, so that the final cost to obtain one unit of dry product is reasonable. It is important to remember that to obtain a ton of cassava dry chips it is required to have 2.5 to 3 tons of fresh cassava roots, and to obtain a ton of dry foliage it is required to have 4 to 5 tons of fresh foliage. The dehydration system based on the use of solar energy has the advantage of eliminating the fuel costs. However, there are many additional limiting factors that have a very important specific effect on the total processing costs. The construction costs for the drying floors is high, the low efficiency per unit of drying surface, the high labor demand, the unpredictable environmental factors (sun, rain, wind) and the risk that exists of sanitary contamination in natural dehydrated products. These factors, associated with other variables, especially in large scale production schemes, indicate that the option of solar energy processing is only recommended in small scale extensions or when, for different reasons, the implementation of mechanical systems of artificial processing is not feasible. Cassava in Poultry Nutrition Figure 8. Sun drying of cassava chips on a cement floor. that to obtain a ton of dry cassava chips, around 250 m2 of drying surface are required during one or two days. With load densities lower than 10 kg/m2, high environmental temperatures, low environment humidity and higher wind velocity, the natural drying process is accelerated. The factors that are most influential in the efficiency of solar drying of cassava roots are as follows: Dehydration with solar energy The most rudimentary method to dry the cassava roots consists in spreading the fragments, pieces or chips over a flat surface (better in cement or asphalt floors), as illustrated in Figure 8, to expose them to the action of solar rays and wind. The moisture content is extracted by evaporation to obtain a final product with less than 15% of humidity. In order to accelerate the process, the cassava chips must be moved and mixed regularly, at least every two hours during the first day, and three or four times the second day, using a wood rake device. The density of the load (amount of chips per unit of drying surface) depends on the environmental conditions; it has been estimated that it should not exceed 10 kg/m2, to obtain an efficient drying in two or three days. This load density means • Geometry of the chips: the speed of drying by solar exposure is directly related to the total surface of the pieces. The drying time could be shorter when the fragments are regular and allow a free circulation of air between them. Rectangular and cubic forms are the best for a quick and uniform drying. • Load per unit of drying surface: the quantity of cassava chips per unit of surface affects the drying speed. Generally, densities higher than 10 kg/m2 are not recommended to obtain an adequate dehydration in one or two days, provided that the environmental conditions are favourable. • Air conditions: the most influent variables on the drying speed are the velocity, temperature and humidity of the surrounding air. At the initial stages of drying, cassava pieces loose humidity faster, therefore the velocity of air is more important than temperature and humidity. During the final stage, when the humidity level is lower than 30%, the dehydration of the pieces is very slow and high temperatures are needed to eliminate 15 Cuadernos Avícolas No. 14 residual water. In the natural drying system, the environmental humidity level is particularly important during the initial stage of the process. A relative humidity level higher than 65% can extend the natural drying process. • Initial moisture content of cassava: the initial moisture content of the cassava chips determines the amount of water that must be extracted and, therefore, the speed of the operation. Likewise, the conversion factor (amount of fresh cassava required to produce a unit of dry cassava) changes in direct proportion to the initial humidity (Table 2). In Table 3 it is possible to observe the effect of the variation of environmental conditions on the drying time of cassava chips using cement drying floors with a high load density (5 kg/m2). Table 2. Effect of the initial moisture content of the cassava roots on the conversion factor. Initial humidity % (a) Dry cassava per kilo of fresh cassava, grams (b) Conversion Factor (c) 75 70 65 60 55 280 335 390 445 500 3.6 3.0 2.6 2.2 2.0 (a) Numbers in humid base (b) Dry cassava quantity with a humidity of up to 10% (c) Fresh cassava units required to obtain a unit of dry cassava equipment and processing. The correct choice of the equipment depends on various factors, specially related to the fuel costs or the heat source and the amount of material to dehydrate. Artificial dehydration methods There are different systems to achieve the dehydration of cassava roots with industrial Considering the high percentage of water that must be eliminated during the process and the relatively low market price of the Table 3. Effect of the environmental conditions on the drying velocity of cassava root pieces * Environmental conditions Temperature o C Relative humidity Wind velocity (m/seg) Solar radiation Cal/cm2.min Drying hours: in cement courts 24 70 1.9 0.73 11 26 67 0.8 0.58 17 26 66 1.2 0.61 15 30 64 0.9 0.65 10 31 68 1.0 0.71 13 * Cement floor with a charge density of 5kg/m2. From: Best and Gómez, 1982. 16 Cassava in Poultry Nutrition final product (cassava flour or cassava chips), in order to compete with other traditional sources of energy, the dehydration costs are a very sensible parameter. For this reason, the use of low cost fuels and the efficiency of the process are important factors in the selection of the dehydration system. A general analysis of formulation costs for balanced feeds indicates that the total processing cost should not exceed 10 to 15%, related to the final price of the dehydrated product (i.e. if the market price for cassava flour is US$150 per ton, the processing cost should not exceed US$ 15 to 22 per ton of dry cassava or US$ 5.75 to 8 per ton of fresh cassava). This processing cost can be achieved with industrial methods such us those based on automatic processes and great volumes schemes. In the process of dehydration with solar energy it is more complicated to achieve permanently processing costs similar to those mentioned above due to the participation of many variables that cannot be easily controlled (solar radiation, rain, drying area, labour, etc.). A few companies in Colombia have been working during the last years in the development of industrial equipment for dehydration. The most recent experiences have showed satisfactory results. Currently, five companies are known for their experiences: Armare (Barranquilla), Industrias Protón (Bogotá), Procesos Agroindustriales (Cali/Buga), Soyagro (Barranquilla) and Muskus (Medellín). These companies base their dehydration processes on the use of gas or steam. The initial and final stages of dehydration are similar in all models and are based in the following basic elements: • Reception of raw material (bulk form) • Roots cleaning and washing (optional) • Root shipping and grating • Initial drying process with of controlled heat to reduce the cianogenic acid level of the cassava roots • Final continuous dehydration process • Reception and packaging The main differences between the equipments are the dehydration system and the type of fuel used, which are reflected in the final processing costs. In the Figures 9, 10, 11 and 12, the basic aspects of these equipments are illustrated. A more detailed information of each equipment and process can be obtained contacting directly the manufacturing companies whose addresses are in the Annex at the end of the present document. In some specific circumstances it is also possible to assemble a mixed or combined dehydration system in which the first part of the drying process is done using solar energy and the final drying is conducted using artificial methods. This combination allows a very significant reduction in investment and processing costs although it requires very favourable climatic conditions for the natural dehydration process. 17 Cuadernos Avícolas No. 14 Figure 9. Armare* model for cassava drying and toasting with natural gas. Figure 10. Protón* model for cassava drying with gas and steam. Figure 11. Agroindustrials* model for cassava drying with natural gas. 18 Figure 12. Flow chart of a typical system to dry and roast cassava chips (Armare company). 12 14 7 1 10 2 8 13 14 4 6 321 321 321 321 321 3 9 11 16 5 15 Engineering Department Barranquilla, Colombia Cassava in Poultry Nutrition 19 1 = transport; 2 = washer; 3 = cassava chipper; 4 = transport belt; 5 = Turbine; 6 = fluidized dryer; 7 = lifter; 8 = fluidized drum dryer; 9 = precooking dryer and release control gate; 10 = turbine; 11 = cyclon; 12 = transport and neumatic cooler; 13 = storage silo; 14 = cyclon; 15 = packaging devier; 16 = neumatic gate. Cuadernos Avícolas No. 14 CASSAVA BYPRODUCTS WITH POTENTIAL TO BE INCLUDED IN POULTRY FEEDING The principal resource offered by cassava for animal feeding is located in the roots, in its starch form. Normally, the dry matter content varies between 34 and 38%, with a starch concentration of 75 to 80%. If the reference is the production of 25 tons of fresh roots per hectare, the net yielding in dry matter and starch is 9.5 and 7 tons, respectively. A small percentage of the dry matter is represented by protein (less than 3.0%) and fibre (less than 4.0%). The aerial part (stems, petioles and leaves) of the cassava plant constitutes an additional source of nutrients for the cattle and poultry sectors. Although the high contents of fibre limits the use of cassava foliage flour in poultry, its high protein and xanthophylls concentration (natural pigments) represents a great resource when it is incorporated in the balanced feed diets in adequate levels. Normally, the cassava crop cultivation is orientated towards obtaining roots during a growing period that oscillates between 8 and 12 months, depending on varieties and environmental conditions. When the roots are being harvested, it is also possible to harvest the useful part of the foliage (superior third) for its immediate processing. In this conventional scheme, foliage yields may fluctuate between 10 to 20% in relation with the roots yield, 20 which also depends on varieties, weather and crop management (plantation density). However, it also exists the possibility to orientate cassava crop towards the exclusive production of foliage, or towards the development of a combined program: crops for the production of roots and crops for the production of foliage. In the case of exclusive production of foliage, the agronomic practices of the crop have substantial variations, because in this modality, foliage harvesting must be made every 2 or 3 months during 1 or 2 years. In these conditions, it is possible to obtain a product of better nutritional quality and with greater yields of green material (up to 40 tons per cut). It is also important in this modality to have reinforcement through irrigation and fertilization practices. CLAYUCA has conducted some studies to evaluate the feasibilite of intensive production systems for cassava foliage. Table 4 includes information about foliage yielding in three different regions of Colombia (Buga, Caicedonia and Ayapel). This preliminary study (CLAYUCA, 2001) compared the effect of different planting densities (112.000, 62.500 y 40.000 plants per hectare) and periodical cuts (every 3 and 6 months at Buga and Caicedonia). The numbers cited correspond to preliminary results of a long-term study. The yield of green material obtained until now have been lower than those obtained in other countries where it has been possible to harvest up to 40 tons per cut. Cassava in Poultry Nutrition Table 4. Yields of intensive cassava leaves production plots in tons per hectare (fresh weight). 112.000 plants per hectare Cutting time (months) 3 6 9 62.500 plants per hectare 40.000 plants per hectare 12 18 3 6 9 12 18 3 6 9 12 18 7.5 12.63 2.27 13.17 6.7 3.37 6.45 3.68 14.03 6.33 3.38 4.56 Buga: MCOL 15015 3.23 10.93 12.79 MCOL 2758 5.58 16.10 12.99 10.02 8.95 5.05 13.70 8.13 5.68 6.97 5.20 23.23 7.13 5.75 4.6 CM 523-7 4.60 13.77 14.12 9.44 12.37 2.60 13.50 8.22 2.93 8.0 6.15 17.23 3.39 2.10 4.89 15.80 18.76 10.16 13.36 18.17 6.46 6.24 5.33 18.3 8.58 13.15 12.37 11.96 16.20 5.43 7.79 3.14 2.94 7.27 10.3 6.99 7.14 12.88 10.60 5.19 5.54 3.12 3.01 4.18 5.49 16.73 22.94 11.65 5.13 11.06 12.19 18.34 3.13 2.74 8.82 9.12 14.05 8.07 2.81 7.28 - 8.00 7.20 5.60 - 10.16 8.6 14.76 3.18 7.08 3.9 - Caicedonia: MPER 183 HMC 1 MCOL 2737 Ayapel: MTAI 8 CM 4918-1 CM 4843-1 21.70 10.60 24.50 - 27.31 18.09 15.87 6.44 27.20 34.96 - 11.90 9.40 12.20 - 11.63 7.76 12.13 5.94 19.81 15.85 From: Rosero, 2001. Non published data. Evaluation, production and quality of foliage in production systems of cassava (Manihot esculenta Crantz), with manual periodical cuttings. (CLAYUCA) NUTRITIONAL CONTENT OF THE MAIN PRODUCTS DERIVED FROM THE CASSAVA CROP main nutritional contents for products, roots and foliage, in its fresh form, just after being harvested. The next two columns illustrate the information about the products in the dried form (with 12-14% of humidity). Main nutrients Table 5 illustrates the nutritional contents of cassava roots and foliage from industrial varieties produced under good management conditions. In the case of roots, we are referring to the integral product (with peels), and with minimum contamination from sand, soil or other residual products. The foliage analysis corresponds to the superior third of the plant (leaves, petioles and secondary stems), harvested simultaneously at the time of harvesting the roots. The first two columns include the Table 6 is included with the purpose of appreciating better the most important nutritional values of the cassava by-products, in comparison with other ingredients of common or potential use in animal feeding. As it has been mentioned before, while cassava roots are characterised by its high content of energy and its low concentration of protein and fatty acids, cassava foliage offers a high level of protein and fibre and a low energy concentration. 21 Cuadernos Avícolas No. 14 Table 5. Main nutrient contents in cassava roots and foliage, % Nutrients Humidity Metabolizable Energy* Protein Fiber Fat Ash Methionine Cystine Lysine Tryptophane Threonine Calcium Phosphorus Potasium Fresh products Roots Foliage 65.000 72.000 Dry products Roots Foliage 12 to 14 12 to 14 1.200 0.340 3 to 3.1 1.380 1.100 1.200 0.470 1.120 0.010 0.008 0.020 6.500 4.700 1.800 1.700 0.070 0.040 0.370 0.050 0.270 0.520 0.090 0.340 2.800 3.200 1.200 2.900 0.030 0.020 0.060 21.000 15.000 5.900 5.600 0.280 0.160 1.600 0.200 1.170 1.700 0.260 1.200 0.010 0.100 0.150 0.250 0.030 0.300 0.400 0.650 * Mcal/kg From: Buitrago, 1990. Table 6. Concentration of metabolizable energy and protein in various products used in animal feeding. Product Fresh cassava root Dry cassava root (flour) Fresh cassava foliage Dry cassava foliage Fresh sweet potato Dry sweet potato (flour) Fresh banana Dry banana (flour) Corn Sorghum Rice Integral soybean From: Buitrago, 1990. 22 Dry Matter % Metabolic Energy Mcal/kg Protein g/kg 35.0 90.0 28.0 90.0 28.0 90.0 20.0 90.0 90.0 90.0 90.0 90.0 1.20 3.05 0.34 1.40 1.03 3.02 0.65 2.85 3.40 3.25 3.15 3.65 12 28 65 210 17 56 10 42 82 88 80 380 Cassava in Poultry Nutrition Considering that under the traditional scheme, the crop is oriented towards the production of roots, the fundamental element of harvesting is represented in starches, which generate an important level of useful (metabolizable) energy for poultry. The production of foliage is secondary in this scheme, although it is possible to obtain important yields of protein to cover part of the protein deficiency of the root. In one hectare of harvested cassava, with a yield of 25 tons of roots, it is possible to obtain around 28 million kilocalories (metabolizable energy) from the roots and more than 200 kg of protein from the foliage. Anti-nutritional factors Cassava roots and foliage contain variable quantities of the glucosides linamarin and lotaustralin, which, when hydrolysed by the action of the enzyme linamarase, generate the free cianogenic acid that can cause toxicity in the animal organism when it is higher than the security levels. (linamarase) Linamarin + water cianogenic acid + acetone + glucose The total cianogenic glucosides or cianogenic acid in the cassava root or foliage determines the difference between bitter varieties (with greater toxicity) and sweet varieties. Although there is not a precise measurement, the varieties considered as bitter are those with a cianogenic acid content superior to 100 mg/kg (100 ppm) for fresh product and the sweet ones have lower levels. In sweet varieties, the greater proportion of cianogenic acid can be found in the peel, while in bitter varieties the acid is distributed evenly in the peel and the parenchyma. Processing methods to eliminate the cianogenic acid in cassava The most effective commercial method to eliminate partially or totally the cianogenic acid content of cassava is based on the controlled action of heat. Temperatures between 40 and 80oC are effective to eliminate the largest portion of the free cianogenic acid. The natural dehydration with solar rays is also a secure system to destroy the cianogenic acid without affecting the action of the linamarase enzyme. The industrial processes of dehydration using heat are also effective, as long as the temperature control corresponds with the temperature ranges required for the detoxification process. VARIATION IN THE NUTRITIONAL QUALITY OF CASSAVA ROOTS AND CASSAVA FOLIAGE FLOUR Cassava Roots flour The quality of roots submitted to the dehydration process to obtain cassava flour has a natural, direct influence in the final quality of the dehydrated product. Roots with contaminated impurities of fibre type (stems, leaves, waste material) or ash type (sand, soil) affect the nutritional quality, reducing principally the energy content. 23 Cuadernos Avícolas No. 14 Roots not processed at the proper time or exposed to deficient, defective or very extended processes, also result affected in their final composition, specially from the sanitary point of view; because they suffer contamination by micro-organisms (bacteria and fungi) that affect the animal’s organism. It does not exist currently an official method to grade the quality of cassava flour for the animal feed industry because of the multiple possibilities of variation during the cultivation, harvesting and processing operations. Table 7 shows a scheme to measure the quality of the roots flour, based on the proposal of Muller et al., 1972, and complemented by the authors of this paper. This initiative refers principally to the parameters of primary importance for determining the energetic value (main contribution of the root), and giving a secondary value to the nutritional elements of less importance on the root (protein, amino acids). Based on the above classification, it is possible to recommend the use of cassava Table 7. Qualification of the nutritional quality of cassava flour. Critical ingredients content Grade Raw fiber % 1 < 2.8 2 < 3.6 3 < 4.5 4 < 5.2 From: Buitrago, 1990. 24 Ashes % Metabolic energy Mcal/kg < 2.0 < 2.5 < 3.2 < 4.0 > 3.30 > 3.15 > 2.92 > 2.60 Table 8. Nutritional composition of cassava flour obtained from peeled and non-peeled roots. Nutrients Dry material Carbohydrates Protein Ether extract Ash Fiber Metabolizable energy Neutral detergent fiber Acid detergent fiber Hemicelulose Roots with peel % Roots without peel % 100.0 83.8 2.90 1.04 3.00 5.10 3.20 5.80 4.70 1.10 100.0 92.4 1.40 0.85 2.20 2.80 3.50 3.20 1.90 1.40 From: Buitrago, 1990. flour, according to more precise nutritional criteria, well adapted to the different animal production stages. In the poultry sector, a first approximation could take into account the following general criteria for the use of cassava flour: First grade: for broiler starters, poultry and laying birds. First and second grade: for layers and reproducers. First, second and third grade: for laying hens, reproducers and layers. In general, it is important to consider that cassava roots are processed in its integral form, that is, including the peel. Normally, the peel represents between 15 and 20% of the total root’s weight, and the pulp or central cylinder represents 80 to 85%. The greater proportion of protein, fat, fibre and minerals (ash) is located in the peel, while the carbohydrates (starches) are located in the pulp. Cassava varieties that produce Cassava in Poultry Nutrition small and tiny roots have, in consequence, a greater proportion of peel, which results in a cassava flour with more fibre, protein and ashes and less energy. Table 9. Nutritional composition of cassava foliage flour with different proportions of leaves, petioles and secondary stem. Table 8 illustrates the existing nutritional differences between cassava flour obtained from non-peeled roots and cassava flour obtained from peeled roots. Nutrients % Leaves* Leaves and Leaf-stalks Protein Ash Fat Fiber Calcium Phosphorus Potassium 22.7 10.9 6.3 11.0 1.68 0.29 0.69 21.6 9.8 6.3 11.6 1.70 0.24 0.60 Cassava foliage flour Although there are no precise specifications about the flour quality that must be produced commercially, it is necessary to recognize some important quality parameters that must be considered to qualify this flour as an adequate product for animal feeding. The aerial part of the cassava plant considered useful for animal feeding has, principally, leaves, petiole, primary and secondary stems. The proportion of participation of these elements to obtain the flour, constitutes the first factor determining the quality of the final product’s quality: if the proportion of leaves is greater related to the other components of the aerial part, then the nutritional quality of the foliage will be better. In order to document these informations, CLAYUCA ordered laboratory tests at the Hoofd Veevoeding company from Holland to evaluate the foliage flour with different proportions of leaves, petioles and stems, taken commercial cultivations in the Valle del Cauca region in Colombia. The results presented in Table 9 illustrate the Leaves, leaf-stalks and stems* 20.2 8.5 5.3 15.2 1.68 0.28 1.09 * Products with 8 to 10% humidity From: Van Poppel, 2001. Analyseuitslagen KB grondstoffen. Hoofd Veevoeding en Kwaliteit, Holanda. differences in the nutritional quality of the samples containing: " only leaves " leaves + petiole " leaves + petiole + secondary stems at the normal proportion during the harvesting of the superior third of the plant. In the results presented in Table 9, it is important to observe that the main change is associated to a greater level of fibre, when the secondary stems participate in the sample. Other nutritional parameters do not vary much, which indicates that the product obtained – when the superior third of the plant is harvested –, can be considered an ingredient similar to the 25 Cuadernos Avícolas No. 14 alfalfa flour and of great potential application in the nutrition of layers and broilers, as a source of protein and natural pigments. It is also important to remember that the variety of the plant, the age, the fertilization practices, the environment and the planting distance affect the quality of the flour. One of the main factors affecting the quality and quantity of cassava foliage nutrients is the age of the material at the time of the cutting. When early cuts are made – for example, 2 or 3 months old – in cultivations oriented towards intensive production of foliage, it is possible to obtain the maximum yield in terms of quality and quantity of nutrients. When the cutting of the foliage is made simultaneously with the harvesting of the roots or when the age of the plant is superior to 8 or 9 months, the proportion of leaves related to the stems is lesser, which has an important effect over the nutritional content of the product as it was explained before. Table 10. Essential amino acid contents in cassava foliage flour. As a percentage of the dry product Methionine 0.36 Lysine 1.87 Threonine 1.35 Leucine 2.72 Arginine 1.48 Fenilalanine 0.92 Tryptophane 0.24 Valine 0.99 Tirosine 0.89 Isoleucine 1.67 From: Buitrago, 1990. As a percentage of the protein 1.3 6.7 4.8 9.7 5.3 3.3 0.8 3.5 3.2 5.9 Likewise, the fibre variations can fluctuate from 10%, if the product has many leaves, to more than 20% in the case of samples with a high proportion of stems. According to the fibre and ashes contents, the concentration of metabolizable energy is calculated between 1.300 and 1.800 kilocalories per kg, approximately. The average content of the main amino acids in cassava foliage flour is illustrated in Table 10. The greater nutritional variations in the foliage flour refer to concentration of protein fibre and metabolizable energy. While the fibre level increases with the age of the plant, the concentration of protein and energy decreases. INCLUSION LEVELS OF CASSAVA FOLIAGE AND CASSAVA ROOTS FLOUR IN POULTRY DIETS The protein content can change from 25%, in cuttings of tender foliage (2 to 3 months old), to values inferior to 20% in more mature foliage and with lower leaves density. Before proceeding to incorporate cassava foliage and cassava roots flour in a program for poultry feeding, it is necessary to analyse some external and internal factors from the production’s environment. 26 Cassava in Poultry Nutrition The most important external factors refer to the production phase for poultry, The processing method (flour, pelleted, crombellized, extruded, etc.) of the final balanced feed product and the complementary ingredients that will be included in the diet. The internal factors are principally related to the quality, availability and price of the cassava products. It is important to take into account that the processing system of the final balanced feed is a fundamental external factor to decide on the level of cassava roots flour that can be included in the diet. Cassava flour is a rather dusty product, very volatile, that causes management problems when it is mixed with other floury products of the diet. This limitation is evident during the fabrication and when the product is given to the animal in its floury form. To counteract this situation, the maximum level of cassava flour inclusion is generally around 25 to 30% or otherwise oil or sugar cane molasses may be added to reduce the dusty feature of the diet. In the case of broilers, it is important to remember that most of the time, the diets are elaborated in form of pelleted, crombellized or extruded products. This modality allows using maximum levels of cassava flour, eliminating the inconveniences of the dusty presentation that characterises the cassava flour In relation with cassava foliage flour, the most limiting external factor for the use of cassava foliage flour is the fibrous characteristic of the foliage that, as it is the case with other types of foliage, does not allows the inclusion of levels higher 6-8% in the final diet. The high fibre concentration and the palatability problems of the forages are directly associated with the low level accepted in poultry diets. However, the low levels of inclusion give, anyway, an important contribution of protein and natural pigments, both in broilers and layers. The quality of the cassava roots or cassava foliage flour depends on many variables as it has been expressed, which are responsible for the final performance obtained in the animal. In the case of poultry, the most precise and relevant measure to evaluate the nutritional quality of the root is the metabolizable energy content; and to evaluate foliage, besides energy, it is important to measure the protein quantity and quality and the xanthophylls concentration. In the feeding programs to be analysed, the inclusion of acceptable quality products is assumed, from the nutritional and sanitary point of view. It is also assumed that the industrial process used guarantees safe levels in the concentration of cianogenic acid (< 100 ppm) in roots or foliage and good criteria in the use of temperature parameters during the processing to maintain the quality of the protein or the xanthophylls in cassava’s foliage. The majority of experiences conducted with broilers and layers, cassava integral root flour (with peels) has been used, which can be classified within grades 1 and 2, according to the grading proposed in Table 7. 27 Cuadernos Avícolas No. 14 Multiple alternatives in feeding programs for broilers and layers can be designed from products that meet adequate quality conditions. Some of these alternatives will be analysed over the next pages, but they just constitute a sample of the numerous possibilities that can be developed in commercial feeding programs. COMPLEMENTARITY OF CASSAVA FLOUR AND INTEGRAL SOYBEANS IN FEEDING PROGRAMS FOR POULTRY Although cassava flour can be complemented with a large number of ingredients that provide the nutrients needed to obtain balanced food rations for poultry, integral soybeans (full – fat soybeans) is presented as a very special and synergetic resource in the design of programs with high nutritional quality. The lack of protein and essential fatty acids that characterize the cassava flour can be amply satisfied with the use of integral soybeans. Indeed, a balanced mixture of cassava flour and integral soybeans can totally cover the requirements of energy, protein and essential fatty acids for broilers and layers. As Table 11 shows, the low concentration in some essential nutrients observed in cassava roots flour is compensated satisfactorily considering the composition of the integral soybeans. Table 11. Main nutrients in cassava flour and integral soybeans. Nutrient Protein Metabolizable energy Fiber Ash Fat Linoleic acid Lecithin Starch Methionine Cystine Lysine Threonine Thryptophane % Cassava roots flour 2.8 Integral soybeans 38.0 Mcal/kg % % % % % % % % % % % 3.0 to 3.2 2.6 3.2 1.2 0.4 0.1 68 0.03 0.02 0.05 0.05 0.02 3.6 to 3.8 4.9 5.2 19 8.9 2.0 8.0 0.51 0.60 2.31 1.43 0.52 Unit From: Buitrago y Luckett, 1999. 28 Cassava in Poultry Nutrition Table 12. Nutritional composition of a cassava flour (82%) and integral soybeans (18%) mixture. Nutrients Cassava flour (82%) + integral soybean (18%) Commercial Corn 9 0.46 0.12 0.24 0.28 0.1 0.51 8.5 0.26 0.18 0.35 0.29 0.07 0.40 3.25 3.5 1.7 3.9 3.6 0.29 0.09 3.34 3.6 2.1 2.8 2.1 0.04 0.08 Protein % Lysine % Methionine % Methionine + cystine % Threonine % Thryptophane % Arginine % Metabolizable energy Mcal/kg % Fat % Linoleic acid % Fiber % Ash % Calcium % Av. phosphorus % From: Buitrago y Luckett, 1999. The specific nutritional requirements for broiler and layer diets offer favourable conditions to be satisfied by different mixtures of cassava flour and integral soybeans. Likewise, this complementarity simplifies the design of feeding programs under commercial conditions. A mixture constituted by 82 parts of cassava flour and 18 parts of integral soybeans becomes a product with similar characteristics to those of cereals, as can be seen in Table 12. The experiences obtained with this type of product (mixture of 82% cassava flour and 18% integral soybean) or with these products used independently, have shown the possibility of obtaining performances and results that are with those of diets elaborated using traditional cereals (corn and sorghum). The integral soybeans can be processed using extrusion or toasting methods. Evaluations conducted using both products have shown similar results. In consideration to the observations discussed above, the following sections of this document will present and discuss various animal feeding programs for poultry (broilers and layers), based on different mixtures of cassava roots flour and processed integral soybean (extruded or toasted). 29 Cuadernos Avícolas No. 14 BROILER FEEDING Considering that the balanced feed for broilers is generally prepared in the form of a pelletized or crombellized product, the recommendations for the levels of cassava roots flour that can be used can be as high as the total substitution of cereal grains in diets for starting and finishing broilers. The dusty feature of diets with high content of cassava roots flour is totally overcome during the pelletization process, without the need to use special additives. This type of diet allows the inclusion of the maximum levels of cassava roots flour (45-50%) and cassava foliage flour (5-6%). When the starting point is the mixture of cassava roots and cassava foliage flour, integral soybeans and Table 13. Example of a complete ration for broilers based on cassava products and integral soybeans. Ingredients % Cassava roots flour Cassava foliage flour Integral soybean (toasted) Soybean meal Palm oil DI - methionine Dicalcium phosphate Calcium carbonate Salt Vitamins and minerals Anticoccidial and additives From: Gil et al., 2000. Roots 45.7 3.0 18.7 2.9 0.29 1.52 0.38 0.3 0.1 + Starter Roots and foliage 40.4 6.0 30.0 16.4 4.5 0.29 1.52 0.38 0.3 0.1 + Roots 49.8 41.6 5.2 0.23 1.52 0.38 0.3 0.1 + Finish Roots and foliage 46.0 6.0 45.1 0.3 0.23 1.5 0.32 0.3 0.1 + Table 14. Nutritional composition of diets for broilers based on cassava products and integral soybeans. Main nutrients Metabolizable energy, mcal/kg Protein, % Methionine, % Methionine + lysine, % Lysine, % Linoleic acid, % Calcium, % Av. Phosphorus, % From: Gil et al., 2000. 30 Roots 3.22 22.00 0.59 0.90 1.26 3.41 0.91 0.42 Starter Roots and foliage 3.22 22.00 0.59 0.90 1.26 3.56 0.91 0.42 Roots 3.18 20.00 0.49 0.78 1.12 3.60 0.96 0.40 Finish Roots and foliage 3.18 20.00 0.49 0.78 1.12 3.85 0.90 0.40 Cassava in Poultry Nutrition Table 15. Diets based on cassava roots flour and cassava leaves flour for broilers in the starting phase. Ingredients % Control Corn Cassava root flour Foliage flour Integral soybeans Palm oil Soybean meal DI-methionine L-Lysine Bone meal Calcium Carbonate Salt Vitamins and minerals 59.37 E. met, mcal/kg Protein, % Methionine, % Met. + Cystine, % Lysine, % Linoleic acid, % Calcium, % Av. phosphorus , % 3.20 22.00 0.59 0.90 1.26 2.62 0.91 0.42 12.80 3.00 21.00 0.16 0.07 1.70 1.50 0.30 0.10 Solar Cassava root's flour Equipment A Equipment B Root flour and foliage flour 45.75 45.75 45.75 30.00 2.90 18.70 0.29 30.00 2.90 18.70 0.29 30.00 2.90 18.70 0.29 40.45 6.00 30.00 4.50 16.40 0.29 1.90 1.90 1.90 1.90 0.30 0.10 0.30 0.10 3.20 22.00 0.59 0.90 1.26 3.42 0.91 0.42 3.20 22.00 0.59 0.90 1.26 3.56 0.91 0.42 0.30 0.30 0.10 0.10 Nutritional Composition 3.20 3.20 22.00 22.00 0.59 0.59 0.90 0.90 1.26 1.26 3.42 3.42 0.91 0.91 0.42 0.42 Table 16. Diets based on cassava roots flour and cassava leaves flour for broilers in the finishing phase. Ingredients % C assava root's flour C ontrol Corn Cassava root flour Foliage flour Integral soybeans Soybean m eal D I-m ethionine L-Lysine Bone m eal Calcium Carbonate Salt V itam ins and m inerals 66.85 E. m et, m cal/kg Protein, % M ethionine, % M et. + Cystine, % Lysine, % Linoleic acid, % Calcium , % A v. phosphorus , % 3.20 20.00 0.49 0.78 1.12 2.20 0.90 0.40 6.10 20.70 0.13 0.19 1.60 1.10 0.30 0.10 R oot flour and foliage flour Solar Equipm ent A Equipm ent B 49.80 49.80 46.11 41.60 5.20 0.23 41.60 5.20 0.23 41.60 5.20 0.23 1.90 1.90 1.90 1.80 0.30 0.10 0.30 0.10 3.20 20.00 0.49 0.78 1.12 3.60 0.90 0.40 3.20 20.00 0.49 0.78 1.12 3.85 0.90 0.40 0.30 0.30 0.10 0.10 N utritional Com position 3.20 3.20 20.00 20.00 0.49 0.49 0.78 0.78 1.12 1.12 3.60 3.60 0.90 0.90 0.40 0.40 46.10 6.00 45.10 0.23 31 Cuadernos Avícolas No. 14 soybean meal, it is possible to formulate a perfectly balanced diet for broilers, in which these ingredients can represent up to 95% of the total feed, as illustrated in Table 13. The nutritional composition of the mixtures already mentioned can be seen in Table 14. Results of feeding programs for broilers with maximum levels of cassava flour CLAYUCA has conducted recently some experimental work (Gil et al., 2001), with the support of Fenavi and the Minister of Agriculture (MADR), to evaluate diets similar to those presented in Table 13. The diets were prepared totally based on cassava flour (from roots and foliage) and integral soybeans and were compared with a commercial ration based on corn and integral soybean. In the case of rations with cassava roots flour, it was possible to compare the effect of cassava flour dehydrated using solar energy and flour dehydrated using equipments available commercially. In Tables 15 and 16 the detailed compositions of the five diets used for broilers (Ross 308) are included. Effects in weight gain and feed conversion: Table 17 illustrates the performance of the broilers until 42 days when the trial was finished. Every group that consumed cassava flour and integral soybeans had a weight gain and feed conversion similar or superior to the control group with corn and integral soybeans. This effect was observed at the starting and at the finishing stage. The consumption of the balanced feed was not affected in the treatments that included high levels of cassava flour. The mortality rates were the same in all the treatments and the diet type did not influence them. Effect of the cassava flour dehydration method: In the treatments that included cassava roots flour, the effect of the natural processing method, by means of the exposure to sun of cassava chips, and the industrial processing with artificial heating (steam and propane gas) were compared, using two commercial equipments currently available (Protón and Agroindustrial Processes). The performance of the chicken was superior when cassava was processed in any of the two equipments mentioned, as can be seen Table 17. Performance of broilers up to 42 days. Parameter % Initial weight, g Final weight, g Consumption, kg Efficiency of feed convertion 32 Control 39.80 2.14 4.73 Solar 39.50 2.28 4.88 2.21 2.14 Cassava root's flour Equipment A Equipment B 39.40 39.50 2.24 2.39 4.65 4.68 2.08 1.96 Root flour and foliage flour 39.70 2.11 4.72 2.24 Cassava in Poultry Nutrition in Table 17. Important differences were not observed when comparing the effect of the two equipments used. Both were effective on the process of dehydration and maintained the final quality of the processed product. The industrial process guarantees high temperatures that facilitate the gelatinisation of starches and allow a better sanitary control of the final product. These two factors have probably an important influence on the superior performance of the animals fed with high cassava roots flour levels, in contrast with the natural sun drying process. Effect on the humidity of the litter Although the diets with high percentage of cassava flour and integral soybeans contain high potassium levels in its final composition, it was not observed an adverse effect related to chicken manure and humid litters. Analysis was made of the humidity of the manure in all the experimental groups, at weekly intervals, and no significant differences were obtained. Additionally, the measure of the humidity of the litter did not indicated differences between groups. group with a diet based on cassava roots flour and cassava foliage flour showed pigmentation similar to that of the control group fed with diets based on yellow corn. The visual appreciation on a scale from 1 (more pale) to 5 (more pigmented), gave the control group and the group fed with cassava roots and cassava foliage flour a qualification of 4, while all the other groups fed with cassava roots flour without cassava foliage flour obtained a grade of 2 on the scale. Results of the feeding programs in broilers with medium and low levels of inclusion of cassava flour Effect on the pigmentation Even though the results obtained replacing totally the cereal grains by cassava flour in pelettised diets have demonstrated that this could become a viable practice in commercial feeding programs for broilers, it is possible that in many occasions, it is more convenient to use a partial substitution of the cereal grains. This last modality is even more important when the diets are prepared in form of flour, considering the floury or dusty characteristic of the diets with percentages of inclusion of cassava roots flour higher than 20 to 30%. An important observation throughout the experiment and by checking at the chicken carcasses after sacrifice, is related with the degree of pigmentation of the skin, legs, mouth and internal fat.. The groups with diets based on cassava roots flour were characterized by a poor pigmentation all throughout the experiment. However, the Tables 18 and 19 illustrate the composition of the diets with intermediate levels of cassava flour, in which the objective was the substitution of about 50% of the sorghum or corn used in diets for the starting and finalization phases. Some experiences have already been conducted with this criterion with an inclusion of around 20 to 30% of cassava roots flour on the diet. 33 Cuadernos Avícolas No. 14 Table 18. Diets for broilers with intermediate levels of cassava flour. Ingredients % Sorghum Cassava roots flour Integral soybeans (toasted) Soybean meal Fish meal(65%) Palm oil Dicalcium phosphate Calcium carbonate DI-methionine Salt Choline chloride (50%) Vitamins and minerals Anticoccidial Fungicide Metabolizable energy, mcal/kg Protein, % Methionine, % Methionine + cystine % Lysine % Thryptophane, % Threonine, % Linoleic acid, % Calcium, % Av. phosphorus, % Starter 33.65 20.00 32.00 8.20 3.50 0.90 0.80 0.27 0.25 0.12 0.10 0.10 0.10 Nutritional facts 3.15 21.00 0.58 0.88 1.23 0.28 0.60 3.08 0.90 0.43 The results obtained in broilers from different genetic lines are illustrated in Tables 20 and 21. In general, it can be concluded that those that consumed diets with a substitution of 50% of cereals for cassava roots flour had the same (or better) performance than those that consumed the conventional diets based on sorghum and corn. In terms of the weight increase, the efficiency of feed conversion and carcass yield, did not present significant differences when compared with the existing treatments, in both place, Avités (Cereté, Córdoba), and El Recreo (Buga, Valle). Adverse effects were not observed in terms of mortality or 34 Finishing 33.61 25.00 34.00 2.80 4.00 0.10 0.70 0.90 0.22 0.25 0.10 0.10 0.10 0.10 3.20 19.00 0.51 0.77 1.10 0.25 0.59 3.10 0.91 0.40 Source: Granjas Avités – Nutrilisto. Cereté, Córdoba. Pelleted diets. morbidity, as a result of the inclusion of cassava roots flour. Differences in humidity of the litter used in the different installations were not appreciable either. LAYERS FEEDING Feeding programs for layers generally involve the use of diets in flour form, which becomes an important limitation for the inclusion of high levels of cassava roots flour. However, when low and intermediate levels of cassava roots flour are used, this situation is no longer a problem for the management of the diets. Cassava in Poultry Nutrition Table 19. Diets for broilers with intermediate levels of cassava flour*. Ingredients % Starter Corn 25.34 Cassava (82%) + soybean (18%)* 30.50 Integral soybean (toasted) 25.90 Soybean meal 12.10 Chicken viscera meal 3.00 Dicalcium phosphate 1.30 Calcium carbonate 1.00 DI-methionine 0.23 Salt 0.35 Vitamins and minerals 0.12 Anticoccidial 0.05 Fungicide 0.10 Nutritional composition E. met, mcal/kg 3.10 Protein, % 22.00 Methionine, % 0.56 Met. + Cystine, % 0.90 Lysine, % 1.24 Thryptophane, % 0.28 Threonine 0.80 Linoleic acid, % 3.25 Calcium, % 0.90 Av. phosphorus, % 0.42 Finishing 30.79 30.50 28.30 4.80 3.00 1.00 0.90 0.10 0.30 0.10 0.10 0.10 3.20 17.00 0.40 0.72 1.10 0.25 0.75 3.48 0.82 0.39 * 82% cassava roots flour + 18% integral soybeans. Granjas El Recreo – Carioca. Buga, Valle Pelleted diets. Table 20. Results on the performance of broilers with intermediate levels of cassava roots flour in the diet. Parameters Starting number Finishing number Number of days Mortality, % Final weight, g Feed consumption, g Feed conversion efficiency European efficiency factor Control 1 Control 2 36.000 33.531 42 6.0 1.951 3.324 1.70 255 48.441 46.199 42 4.6 1.934 3.559 1.84 239 Cassava flour + integral soybean 24.000 22.392 42 6.7 1.915 3.152 1.69 259 Granjas Avités – Nutrilisto. Cereté, Córdoba. 40 m.a.s.l. 34-360 C. Tester 1: Sheds with greater environmental control using ventilators. Tester 2: Sheds with lesser environmental control (like the experimental lot) Pelleted diets. From: Buitrago and Luckett, 1999. 35 Cuadernos Avícolas No. 14 Table 21. Results on the performance of broilers with intermediate levels of cassava flour on the diet. Parameters Control Starting number Finishing number Number of days Mortality, % Final weight, g Feed consumption, g Conversion efficiency European efficiency factor 7.680 7.415 42 3.2 1.976 3.754 1.90 239 Granja El Recreo - Carioca. Buga, Valle. 1010 m.a.s.l. 25-270 C. Pelleted diets. From: Buitrago and Luckett, 1999. Unless the possibility of using pelletised or crombellized diets is considered, it is difficult to incorporate levels higher than 25% of cassava roots flour in diets for layers. The dusty feature and the high starch content difficult the management of the balanced feed with high contents of cassava roots flour. In relation with cassava foliage flour, it is also recommended that its use in diets should not exceed levels of 5 to 6% to minimize effects on the palatability. Likewise, the energy concentration on the diet makes it difficult to include higher levels. When high quality foliage flour is used in the diet in levels of 5 to 6%, a good pigmentation is obtained in the egg’s yolk, due to the presence of natural xanthophylls. 36 Cassava flour + integral soybeans 7.673 7.108 42 5.7 1.942 3.781 1.94 218 RESULTS OF FIELD EXPERIENCES The main field experiences have been conducted in poultry farms located in the Valle del Cauca and the Atlantic Coast regions of Colombia. The evaluations have been developed at different stages of production, using diets, raw materials and nutritional parameter from each place. The first experiences (La Esperanza and Monte Grande farms) were made with double purpose cassava varieties from the Atlantic Coast. In the most recent evaluations (Santa Anita and Avicauca farms) industrial cassava varieties from the north part of Cauca (Agroveléz) were used. The flours from different varieties were mixed to give a homogeneous product as raw material for the elaboration of the final product. In every experimental work, the diets were prepared in the form of flour, and the level of replacement of the corn was 50%. The composition of the diets evaluated in the different demonstrative trials is illustrated in Tables 22, 23, 24 and 25. Cassava in Poultry Nutrition Table 22. Diets for layers with 10% inclusion of cassava roots flour. Ingredients Control Corn 57.80 Cassava flour Soybeans meal 16.20 Toasted soybeans 5.30 Fish meal (65%) 5.00 Wheat bran 3.50 Calcium carbonate 9.71 Calcium phosphate 0.95 Salt 0.30 Liquid methionine (88%) 0.18 Vitamins and minerals 0.10 Additives and pigments 0.50 Nutritional Composition E. metabolizable, mcal/kg 2.75 Protein, % 17.50 Lysine, % 0.91 Methionine, % 0.44 Methionine + Cystine, % 0.75 Calcium, % 3.90 Av. phosphorus, % 0.45 Linoleic acid, % 1.36 Cassava flour 10% 45.30 10.00 15.00 9.10 5.00 3.50 9.64 0.91 0.30 0.20 0.10 0.50 2.75 17.50 0.91 0.44 0.75 3.90 0.45 1.39 Avícola La Esperanza. Buga, Valle. 1000 m.o.s.l. 260 C- 75% R.H. From: Gutiérrez and Martínez, 1998. U. Nacional. The summary of the results obtained with the animal feeding programs cited before is analysed in Tables 26, 27, 28, 29 and 30. No important differences were observed in the production parameters (eggs laying percentage and conversion efficiency). Every production parameter analysed was compared with the normal standards of production for each line and poultry age and the results obtained were always within the normal ranges. Also, in otherparameters such us percentage of mortality or morbidity in lots were poultry consumed diets with intermediate levels of cassava flour, there were not observed any significant differences. The quality and humidity of the litter did not suffer important alterations. 37 Cuadernos Avícolas No. 14 Ingredients Control Corn 41.10 Cassava flour Soybean meal 8.10 Extruded soybean 20.00 Rice polishings 10.00 Wheat bran 9.10 Calcium carbonate 9.60 Calcinated bone meal 1.30 Salt 0.35 DI-methionine 0.18 Vitamins and minerals 0.20 Additives and pigments 0.10 Nutritional Composition Metabolizable energy, 2.75 mcal/kg Protein, % 17.00 Lysine, % 0.85 Methionine, % 0.45 Methionine + Cystine, % 0.70 Calcium, % 3.90 Av. phosphorus, % 0.42 Linoleic acid, % 1.74 Cassava flour 15% 34.10 15.00 11.60 20.00 7.60 9.30 1.50 0.35 0.19 0.20 0.10 2.75 17.00 0.85 0.45 0.70 3.90 0.42 1.37 Granja Avícola Santa Anita. Pradera, Valle. 1010 m.o.s.l. 260 C. 78% R.H. From: ASA, 2000. Granja Avícola Montegrande. Tuluá, Valle. 1025 m.o.s.l. 250 C. 78% R.H. From: Gutiérrez and Martínez, 1998. U. Nacional. 38 Table 23. Diets for layers with 15% inclusion of cassava roots flour. Table 24. Diets for layers with 20% inclusion of cassava roots flour. Ingredients Control Sorghum 30.60 Corn 20.00 Cassava flour Soybeans meal 12.30 Toasted soybeans 15.00 Wheat bran 10.30 Calcium carbonate 9.20 Calcium phosphate 1.40 Salt 0.35 Liquid methionine (88%) 0.23 Vitamins and minerals 0.10 Additives and pigments 0.50 Nutritional Composition Metabolizable energy, mcal/kg 2.70 Protein, % 17.00 Lysine, % 0.85 Methionine, % 0.45 Methionine + Cystine, % 0.70 Calcium, % 3.90 Av. phosphorus, % 0.42 Linoleic acid, % 1.74 Cassava flour 20% 36.20 20.00 16.50 15.00 0.20 9.30 1.60 0.35 0.23 0.10 0.50 2.70 17.00 0.85 0.45 0.70 3.90 0.42 Cassava in Poultry Nutrition Table 25. Diets for white and red layers with 10 and 20% inclusion of cassava roots flour. Cassava flour 10% Corn 41.10 34.10 Cassava flour 10.00 Soybeans meal 8.10 10.40 Extruded soybeans 20.00 20.00 Rice polishings 10.00 10.00 Wheat bran 9.10 4.30 Calcium carbonate 9.60 9.50 Calcinated bone flour 1.30 1.40 Salt 0.35 0.35 DI-methionine 0.18 0.19 Vitamins and minerals 0.20 0.20 Additives and pigments 0.10 0.10 Nutritional Composition Metabolizable energy, mcal/kg 2.70 2.70 Protein, % 17.00 17.00 Lysine, % 0.85 0.85 Methionine, % 0.45 0.45 Methionine + Cystine, % 0.70 0.70 Calcium, % 3.90 3.90 Av. phosphorus, % 0.42 0.42 Linoleic acid, % 1.74 1.49 Ingredients Control Cassava flour 20% 23.00 20.00 11.80 20.00 10.00 3.60 9.40 1.40 0.35 0.21 0.20 0.10 2.70 17.00 0.85 0.45 0.70 3.90 0.42 1.37 Avicauca. Jamundí, Valle. 1005 m.o.s.l. 250 C. 76% R.H. From: ASA, 2000. Table 26. Layers performance with a 10 % inclusion of cassava flour in the diet – from week 48 to 55. Yielding Consumption/hen/day, g Egg laying, % Conversion per dozen of eggs Control Cassava flour 10% 102.6 89.2 1.4 103.2 89.5 1.4 Avícola La Esperanza. Buga, Valle. 1000 m.o.s.l. 260C. 75% R.H. From: Gutiérrez and Martínez, 1998. U. Nacional. 39 Cuadernos Avícolas No. 14 Table 27. Lohmann Brown layers performance with 15% inclusion of cassava flour in the diet – week 55 to 61. Performance Number of layers Consumption/hen/day, g Egg laying, % Conversion per dozen of eggs Control Cassava flour 15% 15.00 114.00 78.30 1.37 5.00 115.00 79.00 1.37 Granja Avícola Santa Anita. Pradera, Valle. 1010 m.o.s.l. 260 C. 78% R.H. From: ASA, 2000. Table 28. Layers performance with 20% inclusion of cassava flour in the diet – weeks 39 to 46. Performance Consumption/hen/day, g Egg laying, % Conversion per dozen of eggs Control Cassava flour 20% 111.6 92.4 1.5 111.1 91.0 1.46 Granja Avícola Montegrande. Tuluá, Valle. 1025 m.o.s.l. 250 C. 78% R.H. From: Gutiérrez and Martínez, 1998. U. Nacional. Table 29. White layers (Hy-Line) performance with 10% inclusion of cassava flour on the diet – week 78 to 88. Yielding Number of layers Consumption/hen/day, g Egg laying, % Conversion per dozen of eggs Control Cassava flour 15% 10.464 107.50 64.10 2.01 8.976 105.50 63.00 2.01 Avicauca. Jamundí, Valle. 1005 m.o.s.l. 250 C. 76% R.H. From: ASA, 1999. 40 Cassava in Poultry Nutrition Table 30. Red layers (Lohmann Brown) performance with 10 and 20% inclusion of cassava flour in the diet – week 78 to 88. Yielding Control Cassava flour 10% Cassava flour 20% 3.840 115.10 69.30 2.00 10.956 115.80 65.70 2.12 5.160 114.80 65.10 2.11 Number of layers Consumption/hen/day, g Egg laying, % Conversion per dozen of eggs Avicauca. Jamundí, Valle. 1005 m.o.s.l. 250 C. 76% R.H. From: ASA, 1999. GENERAL CONCLUSIONS Cassava plants offer two valuable resources for the animal feed industry: roots and foliage. While roots constitute an important source of starch and energy, foliage mainly contributes with protein and natural pigments. In the majority of tropical regions the cassava crop appears as a profitable alternative to partially or totally replace the cereal grains traditionally used for poultry feeding. The concentration of calories obtained per unit of cultivated area amply overcomes the concentration obtained from cereals. The cassava crop adapts easily to a great range of agricultural areas with altitudes under 1.800 m above sea level, where yields of cassava roots and foliage are usually higher than those obtained with other commercial crops. The integration of the cassava crop with poultry production programs demands special efficiency and industrialization schemes to be able to guarantee the cassava volumes needed, at competitive prices, to replace the traditional inputs. The use of high yielding cassava varieties, the mechanization of planting and harvesting, the industrial processes of post-harvest dehydration and the implementation of transportation and continuous processing systems, are some of the fundamental requirements for the establishment of an effective integration with the poultry sector. Recently, some industrial equipment has been developed at the local market for planting and harvesting cassava roots and foliage as well as for the roots and foliage. These advances constitute significant progress in industrial processes of high efficiency, with the subsequent reduction in production costs. The traditional dehydration method of the roots in cement floors is well adapted for small-scale operations. For an industrial operation, in large scale, it is important to introduce artificial systems of dehydration 41 Cuadernos Avícolas No. 14 that guarantee a better nutritional and sanitary quality of the final product. Due to the protein deficiency in the cassava roots flour, the price of this product must be inferior to the corn price, in 25 to 30%, approximately. Figure 13. In relation with cassava foliage flour, it is also recommended that its use in diets should not exceed levels of 5 to 6% to minimize effects on the palatability. SPECIFIC CONCLUSIONS In broiler and layers feeding, cassava roots and cassava foliage flour are excellent sources of energy, protein and natural pigments. Although the level of inclusion of cassava roots in the diets does not have an important limitation, cassava foliage flour must not be included in levels higher than 5 or 6%, in diets for broiler or layers. The fibre content and the low level of energy limit its use in higher percentages. The cassava roots flour has important limitations in the protein and fatty acid content. This is a reason why the balance of the final diet requires an effective complementation of these two nutrients. In numerous experimental works it has been demonstrated that the integral soybeans is an excellent alternative in the majority of the cases. As long as the broiler diet is pelletised, the cassava flour level can totally replace the 42 cereal grains, without affecting the performance. For diets in the form of flour, it is not recommended to include levels higher than 25% of cassava flour, due to the dusty characteristic of the final diet, which causes difficulties in consumption. According to the studies realized, cassava roots flour can totally replace cereals, as long as the diets are pelletized. In the case of diets presented in the form of flour, it is recommended to replace cereals up to 50% for cassava roots flour, which is equivalent to an approximate level of 25% cassava flour in the total diet. Cassava in Poultry Nutrition REFERENCES Best, R. y G. Gómez. 1982. Procesamiento de las raíces de yuca para alimentación animal. En: Domínguez, C.E. (ed). Yuca: Investigación, producción y utilización. International Center for Tropical Agriculture, CIAT. Cali, Colombia 660 pp Buitrago, J. A. 1990. La yuca en alimentación animal. International Center for Tropical Agriculture, CIAT. Cali, Colombia. ISBN 958-9183-10-7. 446 p. Buitrago, J. A. y L. Luckett. 1999. Potencial de la yuca industrial para producción de alimentos animales. Publicación ASA (Asociación Americana de Soya). Reporte de trabajos demostrativos. Cali, Colombia. 27 p. CIAT. International Center for Tropical Agriculture. Cali, Colombia. Annual Reports. Cassava Program CLAYUCA. Latin American and Caribbean Consortium to Support Cassava Research and Development. Technical Reports 2000-2001. Gómez, G. Y J. A. Buitrago. 1982. Effect of processing on nutrient content of feeds: root crops. En: Reichcigl, M. (ed.). Handbook of nutritive value of processed food, vol. II. CRC Presss. Boca Raton, USA. p. 221-239. Gutiérrez, y Martínez. 1998. Efecto de utilizar harina de yuca y soya integral en dietas para aves ponedoras. Zootecnia Faculty. Thesis of degree. U. Nacional. Palmira, Colombia. Mueller, Z., K.C. Chou, K.C. Nash y T.K. Tang 1972. Study of nutritive value of tapioca in economic rations for growing-finishing pigs in the tropics. UNDP Project Sin 67/505. Pig and Poultry Research and Training Institute. Singapore. 35 p. Rosero, D.F. 2001. Evaluation, production and quality of foliage in production systems of cassava (Manihot esculenta Crantz), with manual periodical cuttings. (CLAYUCA) Thesis (Agronomist). U. Nacional. Palmira, Colombia. 48 p. Gil, J. L., G. Escobar y J. A. Buitrago. 2001. Evaluación técnica y económica de cuatro dietas a base de harina de yuca y una dietacomercial para la alimentación de pollos de engorde. Technical Report. CLAYUCA (CIAT). 14 p. 43 Cuadernos Avícolas No. 14 APPENDIX SOME MANUFACTURERS OF CASSAVA PRODUCTION AND PROCESSING EQUIPMENTS: Inversiones ARMARE Ltda.. Calle 42 No. 35-30. A.A. 1015 Phone: (575) 370 90 27 - 379 59 39 Fax: (575) 379 30 34 E- mail: awasembe@celcaribe.net.co Barranquilla, Colombia INGENIERÍA MUSKUS Circular 2 No. 71-28 Phone-fax: (574) 411 42 91 Medellín, Colombia PLANTICENTER. INDUSTRIA DE PLANTADEIRAS LTDA. Avenida Montreal No. 43. Jardim Panorama. Phone-fax: (044) 264 14 31 Sarandi, Paraná, Brasil www.planticenter.com.br EMPRESA METALÚRGICA COLOMBIANA, EMC Carrera 19 No.16-75 PBX (577) 635 23 50 - 635 19 16 A.A. 978 Bucaramanga, Colombia E-mail: emcger@multicomputo.multinet.com.co 44 PROCESOS INDUSTRIALES Calle 6 No. 18-06 Phone: (572) 227 14 20 Buga, Colombia A.A.10938 Cali, Colombia E-mail: paila@telesat.net.co Industrias PROTÓN Ltda. Carrera 53A No.9-42 Phone: (571) 564 30 66 Bogotá, Colombia E-mail: proton@colomsat.net.co STABRA INDUSTRIA COMERCIAL Rua Campo das Palmas 205 Centro Holambra. Phone-fax: (19) 820 11 31 Sao Paulo, Brasil E-mail: stabra@sigmabbs.c