Meeting Abstract

75.1  Monday, Jan. 6 08:00  Reproductive physiology of a euryhaline teleost consuming low levels of highly unsaturated fatty acids PATTERSON, J.T.*; WALKER, F.L.; GREEN, C.G.; Louisiana State Univ. Agricultural Center; Louisiana State Univ. Agricultural Center; Louisiana State Univ. Agricultural Center JPatterson@agcenter.lsu.edu

Relative activities of fatty acid (FA) elongases and desaturases are highly variable in fishes. Generally, freshwater species have the ability to biosynthesize longer chain highly unsaturated fatty acids (HUFA) from unsaturated C₁₈ substrates while marine species have not evolved this ability due to an abundance of highly unsaturated C₂₀ and C₂₂ FA at the base of their food web. De novo biosynthesis of HUFA remains largely unexplored in fishes living at the margin of fresh and salt water. The euryhaline Gulf killifish Fundulus grandis is increasingly used as a model species for teleost physiology. We utilized F. grandis to investigate impacts of dietary HUFA content on reproductive and subsequent larval stress physiology. Four experimental diets were formulated to contain graded amounts of HUFA by incrementally replacing corn oil as the lipid component with marine source fish oil. Diets were fed to replicate tanks during an 8-week inclusion period and 10-weeks of spawning. Gas chromatography was used to quantify FA in eggs, ovary, liver, and muscle. Newly hatched larvae produced by experimental groups were examined for endogenous nutritional resource quantity, upper-limit salinity tolerance, and critical thermal maximum. Low levels of dietary HUFA significantly changed body tissue and egg FA profiles while increasing HUFA in diets resulted in significantly greater endogenous nutritional resources, tolerance of high salinity, and critical thermal maximum. These data further an understanding of the roles HUFA play in the reproductive physiology of teleost fishes.