White Bass (Morone chrysops) Preferentially Retain n-3 PUFA in Ova When Fed Prepared Diets with Varying FA Content.

Abstract

We evaluated the fatty acid (FA) composition of broodstock white bass ova fed one of six commercial diets with increasing polyunsaturated FA content (n-6/n-3 ratio; 0.36, 0.39, 0.46, 0.83, 1.07, 1.12) eight weeks prior to sampling. Fatty acid 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 0.39 diet separated those from the 0.36 diet based on lower 18:2n-6 (LNA) and higher 20:1n-9 concentrations from the 0.36 diet. Ova profiles were further separated based on lower concentrations of 22:5n-3 (DPA) from the 0.46 diet, lower concentrations of 20:5n-3 (EPA) in the 1.12 and 0.83 diets, and lower concentrations of 22:6n-3 (DHA) in all other diets relative to the 0.46 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. There was no correlation between dietary ARA concentrations (0.7-1.1mol%), or dietary EPA/ARA ratios (7-15), and the concentrations (1.4-1.7mol%) or ratios (3.3-4.4) found in the ova by diet. Our results suggest that white bass females have the ability to preferentially incorporate n-3 PUFA, particularly DHA, suggesting mobilization of this FA from other tissues for ova deposition or preferential dietary incorporation of PUFA into ova. These results will add to the limited FA information available in white bass and enable nutritionists to formulate broodstock diets that maximize reproductive potential in this species.