Replacing fish meal with poultry by-product meal in diets for rainbow trout, Oncorhynchus mykiss

Poultry by-product meals are waste material of the poultry industry, which may be used as a valuable animal protein source in diets for rainbow trout. Research in several countries under laboratory and practical conditions has shown that it is possible to replace fish meal in salmonid feeds with different types of poultry by-product meals. The objective of this study was to determine the level of poultry by-product meal that could be used to replace fish meal in practical diets for rainbow trout. Results showed that poultry by-product meal is suitable as a partial or complete replacement, but that complete substitution required amino acid supplementation, principally with lysine and methionine. Fish fed diets with 27% combined poultry by-product and feather meal without amino acid supplementation had feed conversion ratio of 1.15, and body lipid content of 6.1%. Increasing the content of poultry by-product meal in the diet to 50% resulted in a lipid content of 7–8%. These results indicate that a combined poultry by-product and feather meal may be recommended to be a suitable and fish-meal-sparing ingredient in diets for rainbow trout.