Evaluation of Dietary Lipid Sources for the Juvenile Lost River Sucker

Abstract

AbstractThe establishment of a propagation program is among the recommended actions of the U.S. Fish and Wildlife Service recovery plan for the endangered Lost River Sucker Deltistes luxatus. As an initial step in diet development, a feeding trial was conducted to identify appropriate dietary lipid sources to feed juvenile Lost River Suckers at a rate of 0.47 g/fish. Six dietary treatments were produced by adding the following to a basal diet: (1) marine fish oil (Fish) as a control, (2) flaxseed oil (Flax), (3) soybean oil (Soy), or a 1:1 mixture of (4) fish and flax oil (Fish/Flax), (5) fish and soy oil (Fish/Soy), or (6) flax and soy oil (Flax/Soy). At the conclusion of the feeding trial weight gain of fish fed the control diet (Fish) was not significantly different than that of fish fed the other dietary treatments. However, weight gain of fish fed Soy was significantly higher than that of fish fed Fish/Flax. Whole‐body lipid was significantly higher in fish fed Soy than in fish fed Fish, Flax, Fish/Flax, or Fish/Soy, but not significantly different than that in fish fed Flax/Soy. Generally, whole body fatty acid profiles reflected the fatty acid profiles of their respective dietary treatments. These results suggest soybean oil is an appropriate dietary lipid source for the Lost River Sucker, but more research on quantitative dietary requirements is needed for successful propagation of this species.