Effects of Fish Meal Replacement With Alternative Protein Sources in Commercial Scale Extruded Pellets on Growth Performance, Feed Utilization, Biochemical Indices, and Fillet Composition of Atlantic Salmon ( Salmo salar )

This study with two feeding trials evaluated low‐fish meal (FM) diets containing alternative protein sources on growth performance, feed utilization, body composition, innate immune, and blood biochemical parameters of Atlantic salmon ( Salmo salar ). In the first trial, two diets were formulated to contain 60% (FM60) and 30% FM (FM30). FM30 diet was prepared by replacing 50% of FM from the FM60 diet with 11% meat meal (MM), 11% chicken byproduct meal (CBM), 5% krill meal (KM) and 5% soy protein concentrate (SPC). Atlantic salmon averaging 300 ± 1.51 g, were fed FM60, FM30, and a commercial diet for 16 weeks. Growth performance of fish‐fed FM30 diet was significantly reduced compared to that of FM60 group ( p < 0.05). Feed utilization was not significantly affected. Viscerosomatic index (VSI) was significantly higher in FM30 group ( p < 0.05). Muscle omega‐3 level was significantly higher in FM60 group and monounsaturated fatty acid (MUFA) were significantly higher in FM30 group ( p < 0.05). The second trial was conducted to evaluate commercial scale extruded pellets. Three diets (FM60, FM40, and FM30) were formulated with slight modification compared to the first trial. FM40 diet contained 40% FM with MM, CBM, KM, and soybean meal. Atlantic salmon averaging 766 ± 1.51 g were fed three diets and two other commercial diets for 33 weeks. Growth performance, feed utilization, and survival were not significantly affected by the experimental diets. Plasma alkaline phosphate (ALP) level of fish‐fed FM30 diet was significantly higher than the FM60 and FM40 groups ( p < 0.05). Muscle fatty acids were not significantly affected by the experimental diets except for the significantly higher stearic acid (18:0) acid level in FM30 group ( p < 0.05). Muscle color and carotenoid levels were not significantly affected by experimental diets. Therefore, The FM30 diet formulated in the second trial can be used in commercial Atlantic salmon aquaculture without significant negative effects compared to a diet containing 60% FM.