Black Soldier Fly Full-Fat Meal in Atlantic Salmon Nutrition – Part B: Effects on Growth Performance, Feed Utilization, Selected Nutriphysiological Traits and Production Sustainability in Pre-Smolts

Black soldier larva meal (BSFM) seems to be a competitive protein and fat source for widely used fish meal (FM) and fish oil. Because of the still present problem of overfished seas and oceans for feed purposes, even a low substitution of the mentioned feed materials could have a positive impact on the environment. Due to the specificity of salmon metabolic processes, with particular attention to smoltification and the various requirements for nutrients related to individual stages, it is important to implement similar dietary inclusion levels of innovative feed materials in different life stages of Atlantic salmon. Thus, a holistic approach was undertaken in the cycle of two studies carried out: on fries and pre-smolts. This study aims to evaluate the effect of FM replacement by full-fat BSFM in Atlantic salmon pre-smolt diets on growth performance, feed utilization, somatic indices, histomorphology of intestines, colorimetric assessment and raw meat quality, as well as environmental sustainability. The following groups were applied: CON – without addition of full-fat BSFM and with 30% FM; BSFM5 – with 5% addition of full-fat BSFM and 27.1% FM; BSFM10 – with 10% full-fat BSFM and 24.3% FM; and BSFM15 – with 15% addition of full-fat BSFM and 21.3% FM. The present study showed satisfactory results of BSFM inclusion up to 15% as a replacement for FM in feeds for Atlantic salmon pre-smolts. The present study showed that BSFM is a suitable feed material for Atlantic salmon proper diet balancing and may be used to decrease FM content. The semi-technical application of BSFM containing diets confirmed their effectiveness during the growth phase of Atlantic salmon. According to our results, BSFM can be recommended as an alternative feed component in Atlantic salmon pre-smolt nutrition at levels up to 15%. Simultaneously, insect inclusion significantly improved the environmental sustainability of the rearing process.