Dietary Tetradecylthioacetic Acid Supplementation During the Fall Prevents an Increase in Body Lipid Levels but Does Not Influence Precocious Male Maturation Rate in Juvenile Spring Chinook Salmon
Precocious maturation of male fish as two-year-olds occurs at significant rates in spring Chinook salmon hatchery programmes in the Columbia River Basin, representing a loss of production. Precocious maturation is thought to occur due to elevated lipid and other energy reserves in hatchery fish during critical periods for the regulation of gonadal development. To determine whether modification of lipid reserves affects precocious maturation rates in juvenile spring Chinook salmon, we administered feed supplemented with tetradecylthioacetic acid (TTA; a supplement that upregulates lipid oxidation) during the fall critical period one year prior to maturation of precocious individuals. Maturation status was determined the following spring from plasma 11-ketotestosterone levels. TTA administration reduced body lipid levels relative to controls but did not reduce precocious maturation rate. Fish growth was reduced during the TTA feeding period but recovered after fish were returned to a standard diet. No differences in the effect of TTA were found between male and female fish. Our results show that TTA can be used to manipulate body lipid levels in juvenile Chinook salmon but provide no support for a major role of fall body lipid levels in regulating precocious maturation in juvenile male spring Chinook salmon under hatchery conditions.
Pierce, A.L., L.R. Medeiros, B. Hoffman, I.J. Koch, S.R. Narum, P.F. Galbreath, J.J. Nagler. 2021. Dietary tetradecylthioacetic acid supplementation during the fall prevents an increase in body lipid levels but does not influence precocious male maturation rate in juvenile spring Chinook salmon. Aquaculture Research 52(11):5483-5492. Online at https://onlinelibrary.wiley.com/doi/epdf/10.1111/are.15422.