Fungal fermentation to improve the nutritional value of oilseed meal for animal feeds

Soybean meal, serving as gold standard for proteins to formulate animal feeds, dominates the global feed market and makes significant contributions to the overall soybean oilseed plantation processing. Meals made from other oilseeds, like canola, camelina, pennycress, etc. usually have relatively low feeding value as they are rich in non-digestible fiber, low quality protein, anti-nutritional factors such as phytate and glucosinolate, and mycotoxins. These will cause poor animal performance and greatly limit the application level of these oilseed meals in animal feeds. A novel strategy is using pretreatment and fermentation with different hydrolytic and nutritional fungi under solid state fermentation which can be performed at ambient temperature and low water level. Laboratory experiments have demonstrated that these oilseed meals fermented with selected fungi had shown improved essential amino acids, reduced fiber, phytate, glucosinolate and mycotoxins. In addition, dosing low-cost nitrogen source such as urea, ammonia, etc., in fungal fermentation could significantly improve total protein level of the fermented product. Combining pretreatment with fermentation sequentially using different fungal strains could improve in vitro digestibility of protein and amino acids. Techno-economic analysis showed that installation of the solid-state fermentation process for producing nutrient-rich animal feed could have better return on invested capital depending on the market price of high-protein feed.