Traditional and Fermented Soybean Meals as Ingredients in Feeds for White Seabass and Yellowtail Jack

Soybean meal is commonly used as a protein source in aquafeeds, but its benefits can be limited by its digestibility and the presence of antinutritional factors. Fermentation may address both of these issues, thereby improving utilization of soybean meal by carnivorous fish. We compared the production performance of juvenile White Seabass Atractoscion nobilis and Yellowtail Jack Seriola lalandi that were fed diets containing fish meal, or graded levels of traditional soybean meal or fermented soybean meal. These diets were also compared to reduced or fish-meal-free feeds based on soy protein concentrate, poultry byproduct meal, or algal meal (spirulina Spirulina spp.). Complete fish meal replacement yielded poor performance in both species, regardless of the alternative protein source used. White Seabass performed well on diets containing blends of fish meal and traditional or fermented soybean meals or soy protein concentrate; similar results were observed in Yellowtail Jack, though performance was slightly reduced among fish fed the feed containing fermented soybean meal. These results conflict somewhat with investigations of fermented soybean meal in other fish taxa, as well as previous investigations of poultry byproduct meal and spirulina algal meal in White Seabass and Yellowtail Jack. Each of these feedstuffs has potential as a protein source in aquafeeds but presents limitations which must be addressed.