Improved Soybean Feed for Use in Aquaculture

With global aquaculture production poised to double in the next 20 years the need for sustainable, cost effective feed inputs will be greater than ever - and soybean-based feeds can be part of the solution. Unfortunately, soy feeds use remains limited due to the presence of anti-nutritional factors including undigested oligosaccharides raffinose and stachyose, lectins that damage the intestinal lining, and phytate that binds to and prevents the uptake of proteins and essential cations. This is particularly prevalent for high-value carnivorous species such as salmon, char and trout where feed rations can only contain as little as 8% soy meal. Over Phase I of the project, we have identified and characterized at the molecular level allelic series of nonsense and missense mutations in the genes directly responsible for the synthesis of the targeted anti-nutritional factors. We have grown a collection of selected mutants carrying homozygous mutation for each allele of interest. In Phase II, we will fully phenotype the selected homozygotes and isolate the lines with best growth habits as source material for genetic crosses. Genetic crosses will be performed to combine mutated alleles to produce lines with: a single low anti-nutritional trait (low lectin, low oligosaccharides, low phytate), or to combine two, or finally three anti-nutritional traits (low lectin + low oligosaccharides + lower phytate). The effects of each mutation alone or in combination will be evaluated for agronomic performance. The transfer of the traits into elite varieties would start as soon as the phenotype for each trait has been assessed. By the end of Phase II we will produce enough product for a fish feeding study.