Influence of soybean bioactive peptides on growth performance, nutrient utilisation, digestive tract development and intestinal histology in broilers

Summary A biologically active peptide derived from soybeans by enzymatic hydrolysis was evaluated for its potential benefits on chicken growth performance, apparent ileal nutrient digestibility and intestinal histology in young broilers. Seven broiler starter diets, based on maize and soybean meal, were formulated to contain 0.0, 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 g/kg of a commercial soybean bioactive peptide (SBP) product (Fortide, Chengdu Mytech Biotech Co. Ltd., Chengdu, Sichuan, China). All diets were equivalent in respect of energy density, and digestible protein, amino acids, and other nutrients. A total of 336, one-day-old male broilers (Ross 308) were allocated to 42 cages (eight birds/cage), which were randomly assigned to the six dietary treatments. There was no significant effect of SBP on weight gain and feed intake of the birds. A significant (P < 0.01) effect of SBP was observed for FCR. Inclusion of 1.0, 2.0, 3.0 and 4.0 g SBP/kg of feed resulted in similar FCR values to the diet with no SBP, addition of SBP to the diets at 5.0 and 6.0 g/kg of feed resulted in lower (P < 0.05) FCR compared to the diet with no SBP. Inclusion of SBP had no effect (P > 0.05) on apparent ileal digestibility of nutrients and energy utilisation. Though not statistically significant, SBP inclusion, regardless of level, resulted in 5.7% and 6.3% increases in digestibility of dry matter and nitrogen, respectively. Birds receiving no SBP had the shortest villi and those fed SBP at 3.0 and 6.0 g/kg of feed tended (P = 0.075) to have the greatest villus height. The current findings suggested that including SBP in broiler diets may benefit production through improving feed efficiency, and, to some extent, nutrient digestion and intestinal histology parameters.