Fermented soya as an alternative to animal proteins
Developments in fermentation technology offer feed producers a non-animal protein option without sacrificing performance.
Providing piglets with a high-quality protein source is necessary for improved growth and health. Animal protein sources, like blood products and fish meal, have historically been the first choice for piglet feeds, but new developments in fermentation technology now give feed producers a non-animal protein option without sacrificing performance.
Quality versus cost
Protein sources from animal origin are typically utilized for their increased digestibility, palatability, and optimal amino acid profile, but these ingredients are invariably too expensive. More cost effective animal proteins suffer from lower digestibility and variable quality, which contribute to variable animal performance. However, increasing concern about feed and food safety has raised several uncertainties in feeding certain animal proteins, whereas fish meal is becoming a less favorable option due to availability and market volatility. On the other hand, while cost effective, vegetable proteins have not historically been used because of relatively high levels of anti-nutritional factors that limited their inclusion rate in piglet diets.
Advances in fermentation technology have been shown to reduce or eliminate the anti-nutritional factors and improve the nutrient profile of soya, allowing it to be used in piglet diets. The solid-state fermentation of soybean meal has shown to substantially reduce or eliminate raffinose, stachyose and trypsin inhibitor activity, all of which are native to conventional soybean meal. The fermentation process also hydrolyzes proteins, creating small peptides that are easier to digest. Beneficial microbes such as Bacillus spp., Lactobacillus spp. and specific fungi are present in the final product, which can contribute to overall health and productivity in an action not dissimilar to that of a probiotic.
Recent research at the University of Illinois has shown that fermented soybean meal has greater digestible energy, metabolizable energy and net energy than fish meal. Amino acid digestibility was also greater for fermented soybean meal when compared to fish meal. These characteristics alone allow for the substitution of fish meal in piglet starter diets (Table 1).
The research team was also able to show that the fermentation process enhances the total tract phosphorus digestibility. Fermented soybean meal had greater total tract phosphorus digestibility when compared to conventional soybean meal (65.5 versus 46.1 percent, respectively). The addition of the enzyme phytase to the fermented soybean meal treatment increased the total track digestibility from 65.6 percent to 71.9 percent. The addition of phytase to the conventional soybean meal treatment increased the total track phosphorus digestibility from 46.1 percent to 71.4 percent. This implies that feeding fermented soybean meal can potentially reduce the amount of supplemental phosphorus in the diet as it contains more digestible phosphorus than conventional soybean meal.
Additional studies at Kansas State University and the University of Kentucky have shown that various high quality animal proteins can be substituted with fermented soybean meal in piglet diets at levels up to 10 percent of the diet. Piglets fed fermented soybean meal have shown growth characteristics similar to the animal proteins replaced and, in some instances, improved growth traits. Research has shown that replacing animal proteins with fermented soybean meal has no significant impact on piglet performance in phase two and three nursery diets.