ASSESSING THE NUTRITIONAL VALUE OF NOVEL SOYBEAN PRODUCTS IN THE DIET OF ATLANTIC SALMON Salmo salar L.

Atlantic salmon are one of the top consumed species around the world, but the Atlantic salmon feed industry relies on fish meal (FM) as one of the primary dietary protein sources. FM has become an expensive and scarce ingredient and its continued utilization in aquafeeds at high levels is unfeasible. Although soybean meal (SBM) is the foremost protein feedstuff currently used as a surrogate for FM in aquafeeds, salmon are highly sensitive to antinutritional factors (ANF) present in conventional soybean meal (CSBM). However, with processing technologies, ANF in CSBM can be effectively reduced or completely eliminated improving its nutritional value. One of these technologies resulted in EnzoMeal^TM (EM), a product with fewer or undetectable levels of important ANF. Therefore, the objective of this study was to compare the effects of EM inclusion into soybean-based diets for Atlantic salmon (Salmo salar).

A 10-week feeding trial was conducted at NOFIMA's land tank facilities in Sunndalsøra, Norway. Four experimental diets (42% crude protein and 20% crude fat) were designed to replace FM with three soybean products (SBP): CSBM (Control), EM, and soy protein concentrate (SPC). Non-vaccinated Atlantic salmon smolts were stocked into 12 tanks (triplicate tanks per diet) at 60 fish per tank (10.89 kg/ m³), and fed ad libitum. Our results showed significant differences in production performance of Atlantic salmon in response to the different dietary SBP (Table 1). Atlantic salmon fed the diets containing 10% SPC and EM (SPC10_EM10) or 20% SPC (SPC20) displayed significantly higher final weight, weight gain, and thermal growth coefficient than those fed the CSBM20 diet, but did not differ (P > 0.05) from fish fed the diet containing 20% EM (EM20). There were no significant differences in feed intake or feed efficiency among treatments. Processed SBM (EM and SPC) supported higher gut health compared to CSBM, which led to distal intestine soy-induced enteritis. Histology and nutrient digestibility data will also be presented. These results indicate that SPC and EM are more suitable sources of protein than CSBM in the diet of Atlantic salmon.