Rodríguez, D. A., R. C. Sulabo, J. C. González-Vega, and H. H. Stein. 2013. Energy concentration and phosphorus digestibility in canola, cottonseed, and sunflower products fed to growing pigs. J. Anim. Sci. 91(Suppl. 2):116-117 (Abstr.) Link to abstract (.pdf)

Soybean meal is a rich source of digestible amino acids for pigs. However, soybeans contain antinutritional factors such as antigenic proteins, oligosaccharides, lectins, and trypsin inhibitors that make soybeans and conventional soybean meal unsuitable for feeding to weanling pigs in great quantities. Therefore, animal protein is usually included in starter diets for pigs. Because soy protein is less expensive than the animal protein, strategies to reduce the antinutritional factors in soy products have been explored. Fermentation of soybean meal with bacteria such as Aspergillus oryzae and Lactobacillus subtilis eliminates many antinutritional factors, and studies have shown that fermented soybean meal is well-tolerated by weanling pigs. However, there is a lack of data on the digestibility of energy and amino acids in fermented soybean meal. Two experiments were, therefore, conducted to measure the concentration of DE and ME and the digestibility of amino acids in fermented soybean meal and to compare these values to values obtained in conventional soybean meal and fish meal.

Because weanling pigs cannot properly digest soybean meal, animal proteins such as fish meal and spray-dried plasma protein are often used in starter diets. However, the cost of these ingredients has become prohibitive for many swine producers, and new sources of digestible protein for weanling pigs are being sought.

Researchers at the Stein Monogastric Nutrition Lab have been studying a co-product of the production of synthetic L-Threonine, which is used as a supplement in low-protein diets. Synthetic L-Threonine is produced by fermenting a carbohydrate substrate using  bacteria such as E. coli. Threonine is extracted from the fermentation broth. The leftover biomass and substrate have the potential to be used as a feed source, but little is known about its nutritional value. Two experiments were conducted to measure amino acid digestibility and energy concentration in a threonine co-product that is produced by drying this left-over biomass.

Stein, H. H. 2011. Energy and nutrient concentration and digestibility in alternative feed ingredients and recommended inclusion rates. In Proceedings of the American Association of Swine Veterinarians 42nd Annual Meeting. Phoenix, AZ. Link to full text (.pdf)