Effect of enzymolytic soybean meal on growth performance, nutrient digestibility and immune function of growing broilers

Enzymolytic soybean meal (ESBM) produced by fermentation and protease hydrolysis contains less trypsin inhibitors and antigen proteins and more soluble protein and small-size peptides than untreated soybean meal (SBM). This study evaluated the effect of ESBM as a partial replacement for SBM on the growth performance, nutrient digestibility and immune function of broilers from 1 to 21 days old. A total of 336 female Cobb chicks at one day old were randomly allocated to 4 treatments with 6 pens per treatment and 14 chicks per pen. Enzymolytic soybean meal replaced SBM at amounts of 50, 100 or 150 g/kg in a basal maize-soybean meal diet. Feed intake and body weight were measured weekly. On day 21, six birds per replicate were killed, and ileal digesta and peripheral blood were collected for the measurements of nutrient digestibility and immune function. Results show that there were linear increases (P<0.05) in feed intake, body weight gain, gain:feed and coefficients of ileal apparent digestibility of dry matter, crude protein, energy, Ca and P with increased ESBM feeding. The health status of broilers can also be improved due to the linear increases (P<0.05) in the percentages of T lymphocyte, CD4, CD8, IgA, IgG and IgM in peripheral blood, in response to increased ESBM feeding. The results indicate that ESBM could be a novel soybean protein to improve the nutrition and health of growing broilers.