Title: Partial replacement of menhaden oil with Alaskan pollack viceral meal in diets for largemouth bass Micropterus salmoides Authors
Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: November 25, 2009
Publication Date: March 2, 2010
Citation: Lochmann, R., Rawles, S.D., Sink, T., Phillips, H., Barrows, F., Bechtel, P.J. 2010. Partial replacement of menhaden oil with Alaskan pollack viceral meal in diets for largemouth bass Micropterus salmoides [abstract]. Book of Abstracts Aquaculture America 2010. p.622. Technical Abstract: The objective of this study was to determine the effects of replacing menhaden fish meal and oil with APVM in practical diets of largemouth bass (LMB) to sustain or improve general performance while maintaining substantial amounts of the n-3 fatty acids in the fillets. The n-3 highly unsaturated fatty acids (HUFAs) are needed in diets of most carnivorous fishes to maintain a high level of performance and product quality. Supplies of traditional HUFA sources such as menhaden fish meal and oil are dwindling and increasingly costly. Therefore, alternative n-3 HUFA sources are critically needed. Alaskan Pollock visceral meal (APVM) is an underutilized marine by-product with 70% lipid that is rich in n-3 HUFAs. This product may have potential to replace traditional marine products in diets of largemouth bass without sacrificing performance or product quality. A 12-week feeding trial was conducted with LMB weighing 41.3 + or - 0.1 g initially. Three diets were formulated with different amounts of menhaden fish meal and oil, and APVM. These ingredients were manipulated so that APVM replaced 0% (control), 25% or 50% of the menhaden fish meal and oil in the diets. All diets met the nutrient requirements of LMB and were similar in protein and energy content. The diets were extruded as 9-mm floating pellets. Ten fish were stocked in each of four tanks in a recirculating system with municipal water and fed once daily to satiation. Fish were weighed every two weeks to track growth. After final weights were obtained, fish remained on their experimental diets for two more weeks prior to taking tissue samples for health assays (alternative complement and lysozyme activity) and proximate and fatty acid analysis. One week later, a stressor (crowding) was imposed on the fish, and serum cortisol was measured to assess the stress response. There were no differences in weight gain or survival between diets, and additional analyses are in progress.