Evaluation of an alkane yeast (Candida sp.) as a substitute for fish meal in Oregon Moist Pellet: Feeding trials with coho salmon (Oncorhynchus kisutch) and rainbow trout (Salmo gairdneri)

Up to 40% of the fish meal portion of the Oregon Moist Pellet (OMP) was replaced with up to 40% alkane yeast single cell protein (22% of dietary protein) in diets fed to rainbow trout in fresh water, and up to 100% of the fish meal portion was replaced with alkane yeast (54% of dietary protein) in OMP diets fed to coho salmon in salt water. Salmon diets were supplemented with DL-methionine to correct for a suspected deficiency in this essential amino acid. Alkane yeast was an acceptable substitute for fish meal at all levels tested in trout. Only 25% yeast substitution was judged to be acceptable in the OMP diet for marine-cultured coho salmon, causing less than 4% reduction in growth. In marine-cultured coho salmon, growth was depressed further at fish meal substitution levels greater than 25%, while supplementation with DL-methionine enhanced growth and feed conversion only slightly.