Effects of replacing soybean meal, soy protein concentrate, fermented soybean meal or fish meal with enzyme-treated soybean meal on growth performance, nutrient digestibility, antioxidant capacity, immunity and intestinal morphology in weaned pigs

The present study was conducted to evaluate the effects of replacing soybean meal, soy protein concentrate, fermented soybean meal or fish meal with enzyme-treated soybean meal on growth performance, nutrient digestibility, antioxidant capacity, immunity and intestinal morphology in weaned pigs. A total of 216 weaned pigs (initial BW:6.69 ± 0.99 kg) were blocked by BW and sex, and randomly assigned to 6 dietary treatments. Each treatment had 6 replicate pens with 6 pigs (3 barrows and 3 gilts) per pen. The experimental period was divided into 2 stages: phase 1 (d 0 to 14) and phase 2 (d 14 to 28). During d 0 to 14, pigs in ESBM-1 or ESBM-2 had greater (P < 0.05) average daily gain (ADG) than those in CON, SPC or FSBM. On d 14, the apparent total tract digestibility (ATTD) of dry matter (DM), organic matter (OM), crude protein (CP) and gross energy (GE) in pigs fed FM, ESBM-1 and ESBM-2 were greater (P < 0.05) than pigs fed the CON. Pigs fed FM, ESBM-1 and ESBM-2 had higher (P < 0.05) concentrations of superoxide dismutase (SOD), and had lower (P < 0.05) concentration of malondialdehyde (MDA) compared with CON. The concentrations of immunoglobulins G (IgG) and immunoglobulins M (IgM) were higher (P < 0.05) in pigs fed the ESBM-1 and ESBM-2 than pigs fed the CON, SPC and FSBM. On d 28, pigs in ESBM-2 had greater (P < 0.05) ATTD of CP and GE than those in CON, SPC and FSBM. Compared with the CON, SPC and FSBM, pigs in ESBM-2 had higher (P < 0.05) activity of SOD, glutathione peroxidase (GSH-Px) and T-AOC. But the MDA concentration was lower (P < 0.05) in FM, ESBM-1 and ESBM-2 than in CON. The villus height of duodenum was greater (P < 0.05) in ESBM-2 than in other treatments, and the villus height to crypt depth ratio of duodenum was greater (P < 0.05) in ESBM-2 than in CON, SPC and FSBM. In conclusion, enzyme-treated soybean meal can replace soybean meal, soy protein concentrate soy protein concentrate, fermented soybean meal or fish meal in weaned pig diets by improving the growth performance, nutrient digestibility, antioxidant capacity, immunity and intestinal morphology of weaned pigs.