Different Dietary Protein Sources in Low-Protein Diets Induces Changes in Antioxidant Capacity, Immunity, Fecal Microbiota and Metabolites of Weaned Piglets

Abstract

Background: The inclusion of high-quality proteins and the protein restriction are commonly used in swine production. Our study was conducted to evaluate the effects of hydrolyzed wheat protein (HWP), fermented soybean meal (FSBM), and enzyme-treated soybean meal (ESBM) in low-protein diets on antioxidant capacity, immunity, fecal microbiota and metabolites of weaned piglets.Methods: A total of 144 weaned piglets were randomly assigned to 3 dietary treatments with 6 replications of 8 piglets per pen. The experiment was divided into phase 1 ( days 0-14) and phase 2 (days 15-28). The dietary treatments contained 15.90% HWP, 15.80% FSBM, and 15.10% ESBM in phase 1, and 7.90% HWP, 7.80% FSBM, and 7.50% ESBM in phase 2, respectively.Results: The ADG of piglets in the ESBM group was higher (P < 0.05) than HWP and FSBM during days 1-28. Compared with HWP and FSBM, piglets in ESBM had higher (P < 0.05) serum levels of FRAP and SOD on days 14, as well as higher (P < 0.05) serum FRAP level on days 28. Piglets in ESBM had lower (P < 0.05) serum levels of DAO and IL-1β than HWP on day 28. ESBM significantly increased the abundance of Bacteroidetes, Oscillospiraceae and Christensenellaceae and decreased the Clostridiaceae abundance in the feces compared with HWP and FSBM. The PICRUSt analysis revealed that the number of gene tags involved in valine, leucine and isoleucine degradation and lysine degradation in ESBM were lower (P < 0.05) than HWP and FSBM. Piglets in ESBM had higher (P < 0.05) fecal butyrate content compared with FSBM, and ESBM tended to decrease (P = 0.076) fecal cadaverine level.Conclusions: Overall, ESBM had advantages over HWP and FSBM in improving antioxidant capacity, immunity, and fecal microbiota and metabolites of weaned piglets.