Soy protein concentrate replacing animal protein supplements and its impacts on intestinal immune status, intestinal oxidative stress status, nutrient digestibility, mucosa-associated microbiota, and growth performance of nursery pigs.

Due to the high-quality nutrients and functional compounds, animal protein supplements are generally included in nursery pig diets to relieve the negative impacts caused by weaning stress. However, the high cost, short supply, and potential safety issues of animal protein supplements limit their use. Soybean meal is commonly used in swine diets due to the high nutritional values and competitive cost, however, antinutritional factors in soybean meal have been shown to impair the health and growth of nursery pigs. Soy protein concentrate is processed from soybean meal by ethanol extraction and efficiently removes the anti-nutritional factors. The aim of this study was to investigate the effects of soy protein concentrate replacing animal protein supplements at various levels on intestinal immune status, intestinal oxidative stress status, nutrient digestibility, and growth performance of nursery pigs. The use of soy protein concentrate completely replacing animal protein supplements showed benefits on modulating the bacterial ecosystem on the mucosal lining of the small intestine by decreasing potentially harmful bacteria, whereas without affecting intestinal immune status, intestinal oxidative stress status, intestinal morphology, and nutrient digestibility. However, excessive use of soy protein concentrate replacing animal protein supplements decreased the weight gain of nursery pigs due to reduced feed intake.