February 15-18, 2009 Washington State Convention Center Seattle ...

CHANGES IN WHOLE-BODY FATTY ACID CONCENTRATIONS IN FIRST-FEEDING
STEELHEAD Oncorhynchus mykiss FED DIETS CONTAINING PLANT OIL OR MARINE
FISH OIL
Ronald G. Twibell, Ann L. Gannam, Susan L. Ostrand, John S. A. Holmes and Jeff B. Poole
U. S. Fish and Wildlife Service
Abernathy Fish Technology Center
1440 Abernathy Creek Road
Longview, WA 98632 USA
Ronald_twibell@fws.gov
A 12-wk feeding trial was conducted to evaluate the effects of dietary lipids on growth response, carcass proximate composition
and carcass fatty acid concentrations in first-feeding steelhead. The two practical diets included a standard fish meal-based diet
top-coated with marine fish oil (pollock) and a marine product-free diet top-coated with vegetable oil (canola and flaxseed oils).
Each dietary treatment was fed to five replicate groups of 405 randomly selected first-feeding fry reared in fiberglass tanks.
Mean initial weight of the fish was 0.22 g/fish. Fish were collected every two weeks for carcass fatty acid analysis. At the end
of the study, fish fed the diet containing marine fish oil exhibited significantly higher (P