White bass (Morone chrysops) preferentially retain n-3 PUFA in ova when fed prepared diets with varying FA content

Authors: Fuller, Adam; Rawles, Steven - Steve; McEntire, Matthew - Matt; Bader, Troy; Riche, Martin; Beck, Benjamin; Webster, Carl

Submitted to: Lipids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2017
Publication Date: 10/1/2017
Publication URL: https://handle.nal.usda.gov/10113/5806888
Citation: Fuller, S.A., Rawles, S.D., McEntire, M.E., Bader, T.J., Riche, M.A., Beck, B.H., Webster, C.D. 2017. White bass (Morone chrysops) preferentially retain n-3 PUFA in ova when fed prepared diets with varying FA content. Lipids. 52:823-836.

Interpretive Summary: The type of feed fed to commercial broodfish prior to the spawning season, as well as the length of time the feed is fed, tremendously influences the quality, composition, and performance of the resulting eggs and newly hatched fish (fry). In particular, the composition of the dietary fat, i.e., the fatty acid profile, is one of the most influential factors that determine spawning success. White bass females are one half of the parents used to produce commercial hybrid striped bass fingerlings that supply the U.S. grow-out industry. However, there is little research on the nutritional requirements of white bass, especially concerning the effects of different diets on white bass spawning success. As a first step to defining best management practices for pre-spawning white bass brooders, we evaluated six commercial diets currently recommended for broodstock in terms of the fatty acid profile of the diets in comparison to the fatty acid profile resulting in white bass eggs removed from the female fish just prior to spawning. In addition, we examined the fat profiles of the eggs in terms of the amount of time the broodfish were fed the different diets, either 4 weeks or 8 weeks prior to spawning. There were significant differences in the fatty acid composition of the eggs that could be attributed to similar differences in the fat composition of the diets. However, there were also some fatty acids that were preferentially and rather uniformly stored in the eggs even though there were large variations in the availability of those fatty acids in the diets. The storage of some fatty acids could potentially increase survival and performance of developing fry by providing 1) greater energy stores for developing fry, e.g., monounsaturated fats, as well as 2) building blocks for brain, eye, and nervous system development (e.g., long chain omega 3 polyunsaturated fatty acids). The tested diets differed in minor ways in their ability to influence the fat composition of the eggs, while feeding the diets an extra month prior to spawing resulted in a small (2%) but uniform increase in the amount of all fatty acids stored in the eggs.

Technical Abstract: We evaluated the fatty acid composition of broodstock white bass ova fed one of the following commercial diets for four and eight weeks prior to sampling: Zeigler BassBrood-45/15, Bio-Oregon BioBrood™-48/20, Cargill AquaFeed™-45/12, Cargill AquaFeed™-48/18, Skretting Extruded Steelhead-45/16, and Skretting ClassicBrood-46/12. Test diets varied significantly in fatty acid composition. Fatty acid (FA) profiles of ova from brooders fed each of the six diets were significantly altered according to canonical discriminant analysis. Ova FA profiles resulting from the BioBrood diet separated from those from the Cargill-48/18 based on lower 18:2n-6 (linoleic acid) and higher 20:1n-9 concentrations from Cargill-48/18 diet. Ova profiles were further separated based on lower concentrations of 22:5n-6 (DPA) from the Zeigler diet, lower concentrations of 20:5n-3 (EPA) in the Cargill-45/12 and Skretting-46/12 diets, and lower concentrations of 22:6n-3 (DHA) in all other diets relative to the Zeigler diet. Changes in ova FA profile at four and eight weeks were consistent with dietary intake with an approximate 2% increase in any given FA class with increasing time on individual diet. Our results suggest that white bass females have the ability to preferentially incorporate n-3 PUFAs, particularly DHA, into ova.