importancia de los ácidos grasos en la reproducción de peces

IMPORTANCIA DE LOS ÁCIDOS GRASOS
EN LA REPRODUCCIÓN DE PECES
Renata Guimarães Moreira Whitton
Laboratório de Metabolismo e Reprodução de Organismos Aquáticos
Departamento de Fisiologia – IBUSP
renatagm@ib.usp.br
1
Global Fish Production
We have to produce fish if we want to eat fish!
Source: FAO (2014)
2
Changes in PUFA consume during human
development
3
WHAT ABOUT FATTY ACIDS?
4
Function of fatty acids



Energetic source
Regulation of membrane fluidity
Eicosanoid precursor – cell signaling
 Nervous system
 Immune system
 Growth
 Reproduction
 Pigmentation
Esterification
6
7
Cell Membrane Structure
8
9
10
Fatty acids biosynthesis
n6
AA
n3
EPA
DHA
Freshwater and marine fish
Freshwater: PUFAs with 18 C (EFA)
> Enzymatic potential
?
Marine: PUFAs with 20-22C
(EFA)
< Enzymatic potential
How can we apply this context in aquaculture?
-Growth
-Reproduction
Reproduction


Gonadal steroids
HUFAs:
Spermatozoa membranes
AA (n6) - eicosanoids

Oocytes quality (vitelogenesis)

Spawning
DHA (n3) – membranes
(neuronal and photoreceptor)

Ontogenesis
EPA (n3) – eicosanoids

Larval survival
Izquierdo, 2001
Diet
Aquaculture
PUFAs C20-22 n3
EPA and DHA
Sustainability – Low cost
PUFAs C18
18:2n6
18:3n3
Enzyme ability of species
FATTY ACIDS IN LARVAE DEVELOPMENT
(Wiegand, 1996)
16
Which are the fatty acid requirements for
tropical fish species?
17
Influence of broodstock dietary fatty acids on egg and larvae
lipid composition in the tropical teleost Piaractus
mesopotamicus
Corn oil (C18:2n6)
Fish oil (C20:5 n3 + C22:6n3)
National Research Center on Tropical Aquaculture
•Main objectives:
•LIPID AND FATTY ACID PROFILE DURING Piaractus mesopotamicus
REPRODUCTIVE CYCLE;
•INFLUENCE OF DIFFERENT SOURCES OF FATTY ACIDS IN THE FATTY
ACID PROFILE OF THE FAT STORAGE ORGANS;
•INFLUENCE OF DIFFERENT SOURCES OF FATTY ACIDS IN EGG
COMPOSITION;
22
•Experimental Period: 12 months
Animals divided in 3 groups:
A - Control - no oil added in the diet
B - Corn oil added in the diet
C - Corn oil + cod liver oil added in the diet
•Tissues analyzed: Total Lipids; Fatty acid profile
Liver
Ovaries
Fat
Eggs
Classification in maturation stages:
-Resting
-Initial Maturation
-Medium (intermediate) Maturation
-Advanced Maturation
-Regression
LIPID CONTENT DURING THE REPRODUCTIVE
CYCLE
OVARIES
LIVER
TOTAL LIPID - OVARIES
TOTAL LIPID - LIVER
20
b
20
15
10
a
a
5
a
TOTAL LIPID (%)
TOTAL LIPIDS (%)
b
b
ab
15
10
ab
a
a
5
0
0
MATURATION STAGES
MATURATION STAGES
LIPID CONTENT DURING THE REPRODUCTIVE
CYCLE
NEUTRAL AND POLAR LIPID - LIVER
NEUTRAL AND POLAR LIPIDS - OVARIES
100%
100%
80%
60%
PL
40%
NL
(%)
(%)
80%
60%
PL
40%
NL
20%
20%
0%
0%
MATURATION STAGES
MATURATION STAGES
EPA Composition - Advanced Maturation
AA Composition-Advanced Maturation
8
1
7
0,8
%
6
4
3
*
0,6
*
0,4
*
0,2
2
0
1
0
DHA Composition - Advanced Maturation
%
%
5
*
18
16
14
12
10
8
6
4
2
0
*
*
Control
Corn oil
Corn + cod oil
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INFLUENCE OF DIFFERENT SOURCES OF FATTY ACIDS IN THE
REPRODUCTIVE SUCCESS
Piaractus mesopotamicus - Larval Survival
30
25
20
% 15
10
5
0
Control
n-6
n-6 + n-3
TREATMENTS
Piaractus mesopotamicus-Larval Total Weight
Piaractus mesopotamicus - Larval Total Length
50
*
30
(mg)
(mm)
40
20
10
0
Control
n-6
TREATMENTS
n-6+n-3
1600
1400
1200
1000
800
600
400
200
0
*
Control
n-6
n-6+n-3
TREATMENTS
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INFLUENCE OF DIFFERENT SOURCES OF FATTY ACIDS IN THE
REPRODUCTIVE SUCCESS
Triacylglycerol content of larvae from
broodstock fed differently enriched diets
Phospholipid content of larvae from broodstock
fed differently enriched diets
70
50
60
50
PL (%)
TAG(%)
40
30
20
40
30
20
10
10
0
0
4 DAYS
4 DAYS
9 DAYS
CONTROL
CONTROL
CORN OIL
9 DAYS
17 DAYS
17 DAYS
CORN OIL
COD + CORN OIL
COD + CORN OIL
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Eggs Polar Lipids
30
7
6
5
4
3
2
1
0
b
b
a
b
a a
a
b
20
a
a a
b
25
(%)
(%)
Eggs Neutral Lipids
a
15
a
10
b
a
a
b
5
n3
n6
0
n3/n6
n3
b
Control
Corn Oil
n6
n3/n6
Corn + Cod Oil
Control
Corn Oil
Corn + Cod Oil
Eggs Neutral Lipids - DHA, EPA and AA
Eggs Polar Lipids - DHA, EPA and AA
1,5
1,0
0,5
b
a
a
c
a
0,0
DHA
Control
EPA
Corn Oil
AA
25
20
15
10
5
0
a
b
a
Control
DHA/EPA:
b
a
a
DHA
Corn + Cod Oil
- Corn oil diet (37% of linoleic) and no AA
- Elongation of LA to AA in freshwater
(%)
(%)
b
EPA
Corn Oil
AA
Corn + Cod Oil
diet = 1.6
neutral fraction = 3.5
polar fraction = 13.2
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CONCLUSIONS
1) The amount of total lipids in the ovaries increases as maturation advances, reaching the
maximum value in the advanced maturation stage. In the liver, high values for total lipids
were found in the intermediary maturation stage.
2.1) Females fed the corn oil diet have an increase in the amount of arachidonic acid (20:4
n-6, AA) in the ovaries in the maturation phase, suggesting that the linoleic acid (18:2 n-6,
LA) can be elongated and desaturated to AA.
2.2) The animals fed the corn + cod oil diet, increase the n-3 fatty acids amount in all the
tissues during maturation. The data suggest that docosahaexanoic acid (22:6 n-3; DHA) is
the main n-3 fatty acid. EPA increases in the ovaries and adipose tissue of animals at
advanced maturation, but the total amount is very low.
2.3) DHA, an essential fatty acid in cold water marine fish species, seems to be more
important than EPA or AA in P. mesopotamicus, and can be accumulated in adipose tissue,
liver and ovaries in this warmwater broodstock.
3) P. mesopotamicus mobilizes essential n-3 and n-6 FA to the ovaries selectively, compared
to the diet. The evidence suggests that they can also elongate and desaturate the FA chains.
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