Total to partial fishmeal substitution for poultry byproduct meal (Petfood grade) in aquafeeds, either alone or enriched with acid fish silage, for juveniles of rainbow trout (Oncorhynchus mykiss).

Abstract

Aquafeeds are usually formulated with high fishmeal content as protein source, usually produced using pelagic fish resulting in a reduction of fish products for human consumption. Therefore it is of importance to find appropriate alternatives to produce formulated aquafeeds with least possible fishmeal or none. There are several reports that demonstrate the positive effect of poultry by-product meal (PBM) in aquafeeds for different fish species, unless the amount of essential fatty acids. Thus, the present work was design to show the effect of PBM alone and enriched with acid fish silage using fishery by-products by a co-drying process, to substitute the fishmeal at different levels to evaluate the rainbow ( Oncorhynchus mykiss ) performance. Thus six diets were formulated at different levels of substitution of fishmeal; three with PBM pet feed grade (33, 66 and 100 %), and other three diets at similar levels but made out with enriched PBM (EPBM) after mixing 60:40 (weight:volume) with acid fish silage from tuna fish by-products. All treatments were formulated to contain similar protein and energy. After 22 weeks the diet containing 100 % EPBM achieved the significant highest specific growth rate (2.0 % d -1 ), whereas the lowest was observed with the PBM33 without enrichment (1.76 % d -1 , respectively). The present results demonstrate that a combination of poultry byproduct meal with acid fish silage made from tuna fishery by-products results in a better performance.