β-Glucanase-producing bacterial culture improves performance and nutrient utilization and alters gut morphology of broilers fed a barley-based diet

The present study was conducted to evaluate the efficacy of an Escherichia coli DH5-α strain producing β-glucanase from Streptococcus bovis on growth performance, diet utilization and the gut morphology of broilers. One hundred and twenty 1-day-old chicks (Cobb 500) were randomly divided into three groups with five replicate pens of eight chicks and assigned to receive maize-based diet (MBD)+, barley-based diet (BBD), BBD with addition of bacteria producing β-glucanase via water (BBDG). Replacing maize with barley in the diets resulted in growth depression despite containing equal amounts of energy and protein (P<0.01). Birds in the group BBDG consumed more feed (86 g/day vs. 84 g/day), grew faster (51.0 g/day vs. 43.2 g/day) and had better feed conversion (1.95 feed g/gain g vs. 1.68 feed g/gain g) than those in the group BBD. Inclusion of E. coli decreased the pancreas weight (P<0.05) but did not affect the liver weight and duodenum, jejunum, ileum, and cecum lengths. Villus length and width, but not crypt width and depth decreased in response to replacement maize with barley in the diets (P<0.05). However, provision of E. coli strain ameliorated the decreases in villus length by 8.5% and width by 7.9% resulting from barley feeding (P<0.05). Crypt depth and crypt width were unresponsive to the bacterial treatment. The barley-based diet decreased nutrient digestibility compared with the MBD (P<0.05). Addition of E. coli strain via water caused improvements in the coefficient of total tract apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP) and ether extract (EE) (P<0.05). The present data indicated that supplementation of an E. coli strain capable of producing β-glucanase with broilers improved nutritive value of barley through altering its digestibility and intestinal morphology.