Effects of dietary n-3 and n-6 fatty acids levels on egg and larval quality of Eurasian perch

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three groups of 40 perch breeders were reared in order to study the effects of 3 different levels of dietary n-3 and n-6 fatty acids on egg quality. two experimental diets, r1 and r2 (n-3/n-6 = 0.13 and 35.54, respectively), were compared to one commercial food, r3 (n-3/n-6 = 3.48). spawning and fertilization rates were high for diets r1 and r3, which displayed a n-3/n-6 ratio of 0.77 and 2.34 in the eggs, respectively, by comparison with r2 (n-3/n-6 = 4.87), which produced low reproductive performances. We can conclude that dietary n-3 and n-6 FA levels influence egg and larval...

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Nội dung Text: Effects of dietary n-3 and n-6 fatty acids levels on egg and larval quality of Eurasian perch

Effects of dietary n-3 and n-6 fatty acids levels on egg and larval quality of Eurasian perch by Émilie Henrotte (1), Julia Lynne overton (2) & Patrick Kestemont (1) AbsTrAcT. - three groups of 40 perch breeders were reared in order to study the effects of 3 different levels of dietary n-3 and n-6 fatty acids on egg quality. two experimental diets, r1 and r2 (n-3/n-6 = 0.13 and 35.54, respectively), were compared to one commercial food, r3 (n-3/n-6 = 3.48). spawning and fertilization rates were high for diets r1 and r3, which displayed a n-3/n-6 ratio of 0.77 and 2.34 in the eggs, respectively, by comparison with r2 (n-3/n-6 = 4.87), which produced low reproductive performances. We can conclude that dietary n-3 and n-6 FA levels influence egg and larval quality of eurasian perch. Key words. - Perca fluviatilis - egg quality - Fatty acids. Introduction ness was comparable between r1 and r3 (74.2 ± 25.0% and one of the major constraints for the development of eur- 69.0 ± 24.2% survival, respectively). the present results asian perch culture is the supply of good quality eggs. the show the same relationship between fish diet and FA compo- importance of 3 fatty acids (FAs; docosahexaenoic (22:6n-3; sition of the eggs produced. r1 and r3 displayed a n-3/n-6 DHA), eicosapentaenoic (20:5n-3; ePA) and arachidonic ratio of 0.77 and 2.34 in the eggs respectively, while the (20:4n-6; ArA) acids) in the reproduction and egg quality spawnings obtained for r2 displayed a ratio of 4.87 (tab. I), has been demonstrated (Bell et al., 1997). As a result of which can be correlated to low reproductive performances, chemical similarities among these particular FAs, leading to specifically regarding the spawning rate, but also regarding competitive interactions, the optimal requirement for each the percentage of fertilized spawnings. our results indicate individual FA is difficult to assess. the objective of this that the spawning quality of perch is directly affected by the study was to determine the FA composition of eggs obtained n-6 FA content of broodstock diet. As opposed to mammal from broodstock fed different n-3 and n-6 FAs levels in rela- cells, which contain essentially n-6 FAs in their PUFA, fish tion with reproductive performances, egg quality and larval cells contain a high level of ePA and DHA, and, consequent- robustness. ly, need those FAs in their diet. However, despite the elevat- ed levels of ePA and DHA, ArA is the chief precursor of the Methods eicosanoids, generating 2-series prostanoids (Lands, 1989), three groups of 40 perch breeders were reared in order which may act on the induction process of the ovulation as to test different levels of dietary n-3 and n-6 FAs (16% lip- well as on spawning. ids) during 9 months (from march to november 2006). two experimental diets, r1 and r2 (n-3/n-6 = 0.13 and 35.54, conclusion respectively), were compared to one commercial fish diet, It is possible to improve the reproductive performances r3 (n-3/n-6 = 3.48). spawning and fertilization rates were as well as the egg and larval quality in eurasian perch by checked in november, and larval robustness was evaluated manipulating the fatty acid composition of the broodstock by osmotic shock (1 hour in naCl 2%, 20°C) two days after diet. hatching. total lipid and FAs were extracted from the eggs Acknowledgements. - this work was support by the european and tested diets. Data were compared by analysis of variance Union CrAFt Percatech project (CooPt-Ct-2004-512629) and AnovA1 (statistica 5.5). by a FrIA grant. results and discussion the survival of broodstock was similar among the table I. - Fatty acid composition of eggs of eurasian perch (% of total FAs). three diets. the spawning rate was high for r1 and Significant differences (p < 0.05) are indicated with different letters. r3 (85.7 and 73.3%, respectively) while only few spawnings were obtained for r2 (33.3%). For 12 egg strands, only one was fertilized in r2, while 38.9 and 72.7% of the spawnings were fertilized in r1 and r3, respectively, with similar fertilization rates in these groups (88.6 ± 10.4 and 87.4 ± 15.1%). Larval robust- (1) the University of namur, 61 rue de Bruxelles, 5000 namur, Belgium. [emilie.henrotte@fundp.ac.be] (2) Danish Institute of Fisheries research, Dept. Aquaculture and marine ecology, Kavalergården 6, 2920 Charlottenlund, Denmark. Cybium 2008, 32(2) suppl.: 271-272.
Eurasian perch egg and larval quality Henrotte et al. references BeLL J.G., FArnDALe B.m., BrUCe m.P., nAvAs J.m. & m. CArILLo, 1997. - effects of broodstock dietary lipid on fatty acid compositions of eggs from sea bass (Dicentrarchus labrax). Aquaculture, 149: 107-119. LAnDs, W.e.m., 1989. - Differences in n-3 and n-6 eicosanoid precursor. In: Advances in prostaglandin, thromboxane and leu- kotriene research (samuelsson B., Wong P.Y.K. & F.F. sun, eds), pp. 602-605. new York: raven Press. 272 Cybium 2008, 32(2) suppl.