NEEDS INNOVATIVE SOLUTIONS Szarek J., Szynaka B.1

NEEDS INNOVATIVE SOLUTIONS Szarek J., Szynaka B.1

MORPHOLOGICAL STUDIES ANSWER THE QUESTION
WHY THE REARING OF THE RAINBOW TROUT
(ONCORHYNCHUS MYKISS WALBAUM, 1972) NEEDS
INNOVATIVE SOLUTIONS
Szarek J., Szynaka B.1, Andrzejewska A.1, Babińska I., Wiśniewska A. M.,
Wąsowicz K., Dobosz S.2, Skibniewska K. A., Dublan K.
University of Warmia and Mazury, Olsztyn, Poland; 1Medical University of Białystok, Poland;
2 Polish Academy of Sciences, Rutki, Poland
e-mail: Szarek@uwm.edu.pl
INTRODUCTION
The morphological examination may be used as a tool for
monitoring the health condition of fish.
MATERIAL AND METHODS
The studies were conducted between 2010 and 2012 in the spring
and autumn in 6 rainbow trout farms: 3 with a flow through
system (FTS) – on 480 rainbow trouts (group 1) and
3 with a recirculation aquaculture system (RAS) – on 480 trouts
(group 2). Liver was collected for studies. Sections of liver were
stained with HE. Material for ultrastructural examinations was
contrast-stained with 0,5% uranyl acetate and lead citrate in
Ringer solution.
Table 1. Evaluation of differences, microscopic parameters of the
liver. Results U – test (Manna - Whitney test) - no statistically
significant differences; p = 0,05.
Rang-sum Rang-sum
FTS
RAS
Parameter
necrosis
degen. adiposa
degen. parenchym.
congestion
extravasation
melanomacroph.
limphoidal cells
20,0
14,0
14,0
16,5
14,0
18,0
13,0
16,0
22,0
22,0
19,5
22,0
18,0
23,0
U
Z
p
6,0
4,0
4,0
6,5
4,0
8,0
3,0
0,433
-1,010
-1,010
-0,289
-1,010
0,144
-1,299
0,665
0,312
0,312
0,773
0,312
0,885
0,194
FTS
FTS
RAS
RAS
RESULTS
Macroscopically lesions of skin and scales were observed (more
frequent in the group 2). Microscopic analysis of the liver of the
rainbow trouts showed in the majority of the fish the normal
pattern (independently from the body mass and rearing system).
Steatosis simplex and hyperaemia were found comparatively
often, especially in the group 2. Quantitatively, more lesions were
found in the fish of the group 2, however the difference was
statistically insignificant. Ultrastructural studies showed
comparatively often small alterations of the mitochondrial
structure (oedema, dense bodies), sporadically the loss of cristae
structure and matrix rarefication - figs. Seldom alterations were
concerning the rough endoplasmic reticulum.
DISCUSSION
The intensivity of liver lesions was higher in the fish from the
intensive rearing system. The obtained pattern allows to claim
that the most sensitive issue of the RAS technology is assurance
of cellular respiration – the appropriate water temperature and
oxygen concentration. It makes the water oxygen concentration
monitoring necessary.
Table 2. The mean of the water quality parameters: oxygen
saturation (O2) and % oxygen saturation (%02) in the inflowing
waters into the fish farms in the course of research in the years
2010-2011 (* values less than the capacity of assimilation).
Parameter Technology Mean
O2
Standard
Minimum Maximum
deviation
FTS
9,61
7,15
10,69
0,857
RAS
8,34
5,68
10,41
1,56
FTS
89,66
*64,13
105,47
11,07
RAS
75,15
*51,66
91,47
13,70
ACKNOWLEDGEMENT
The research has received funding from the European Union and Ministry
of Agriculture and Rural Development – under grant “PO Fish 2007-2013”,
agreement no. 00001-61724-OR1400002/10.
%O2
The 2nd Joint European Congress of the 32nd Meeting of the European Society of Veterinary Pathology, 12th Meeting of the European Society of Toxicologic Pathology and 25th Meeting of the European College of Veterinary Pathologists,
Berlin, Germany, 2014.