Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 5, 2007
Publication Date: May 16, 2007
Citation: Aksoy, M., Lim, C.E., Shelby, R.A., Klesius, P.H. 2007. Effect of Dietary Levels of Menhaden Fish Oil and Feeding Duration on Growth Performance, and Proximate and Fatty Acid Composition of Channel Catfish, Ictalurus punctatus. Meeting Abstract. 32nd Fish Feed and Nutrition Workshop, Auburn University, Auburn, AL, May 16, 2007. Technical Abstract: Omega-3 highly unsaturated fatty acids (HUFA n-3), which consist mainly of eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3), plays vital roles in human nutrition, disease prevention and health promotion. As the general public becomes aware of the health benefits of consuming seafood high in n-3 HUFA, the content of these fatty acids in aquaculture products could become a major factor in determining consumer acceptance in the future. To ensure continued growth of channel catfish, industry, quality of catfish products has to be maintained and improved with regards to the quality of lipids. The effect of supplemental menhaden fish oil levels and feeding duration on growth performance, and tissue proximate and fatty acid (FA) composition of juvenile channel catfish, Ictalurus punctatus was evaluated. Fish in quadruplicate aquaria were fed to apparent satiation with a commercial diet containing 5.6% lipid supplemented with menhaden fish oil at levels of 0, 3, 6 and 9% twice daily for 15 weeks. Levels of dietary fish oil did not significantly influence final weight gain, feed intake, feed and protein efficiency ratios and survival of channel catfish. Tissue lipid contents were directly correlated to dietary lipid levels, while moisture contents were inversely related to dietary lipid levels. Fillet moisture contents progressively decreased whereas fillet lipid increased with increasing feeding duration. Protein contents of both whole body and fillet of fish fed higher fish oil diets were significantly lower than that of the control. Fatty acid compositions of whole-body, fillet and liver were influenced by dietary fatty acid composition. Significant increase in saturated and total n-3 fatty acids, and decrease in monoenoic and total n-6 FA in whole-body and fillet were observed at each incremental level of dietary fish oil, with fish fed the 9% fish oil diet had significantly higher level of total n-3, n-3 HUFA. Percentages of n-3 and n-3 HUFA in fillet of fish fed the control and 3% fish oil diets decreased with increasing feeding periods, whereas those of fish fed 6 or 9% added fish oil diets remained stable or increased. Ratios of n-3/n-6 were statistically comparable throughout the 15-week feeding, although the values at weeks 9, 12 and 15 were numerically lower than that at week 6. When expressed in terms of mg/g fillet, the highest concentration of n-3 was obtained in fillets of fish fed the 9% added fish oil diet for 15 weeks.