Effects of histidine on growth performance of North American Atlantic salmon

Abstract

Atlantic salmon (Salmo salar) producers harvest over 2.4 million metric tons each year. Salmon feed producers are now including higher levels of alternative proteins due to fish meal production limits and consumer demand for more efficient and sustainable ingredients. We examined the effects of histidine in smolt (~355 g/fish) and juvenile (~600 g/fish) North American St. John River strain Atlantic salmon. Salmon were fed graded levels of histidine (0.5, 0.7, 0.9, 1.1, 1.3, and 1.5%) to determine optimum levels necessary to support growth. In the first trial, only percent gain was ranged between 157 to 225%, while thermal growth coefficient (TGC) 1.6–2.0, and FCR ~1 were similar. In the smolt first trial, the final percent gain ranged between 157 and 225%, thermal growth coefficient (TGC) was 1.6–2.0, and feed conversion ratio (FCR) was approximately 1.0. Regression analysis indicated that maximum growth occurred at a dietary histidine level of 0.9% (p =.0012). In the juvenile trial, percent weight gain ranged 35–45%, TGC ranged from 1.4 to 1.9, and FCR ranged from 1.1 to 1.3; these responses were not different between diets. Cataracts were observed in only 3 fish between both studies (3% of the total population). Using regression analysis, both studies suggest histidine levels of at least 0.9% of the diet adequately support Atlantic salmon growth.