Novel probiotics: Their effects on growth performance, gut development, microbial community and activity of broiler chickens.

A total of 294 one-day-old Cobb broiler chickens were used to investigate the effects of four strains on gut microbial profile and production performance. The six dietary treatments, each with 7 replicates were: 1) basal diet (negative control), 2) one of four strains of (tentatively identified as , and an unidentified sp.) and 3) basal diet with added zinc-bacitracin (ZnB, 50 mg/kg). Results showed that the addition of probiotic spp. to the feed did not significantly improve weight gain, feed intake and feed conversion rate (FCR) of broiler chickens raised in cages during the 6-week experimental period, but tended to increase the number of total anaerobic bacteria in the ileum and caeca, and the number of lactic acid bacteria and lactobacilli in the caeca; and to significantly increase the small intestinal weight (jejunum and ileum). Furthermore, all 4 probiotics tended to reduce the number of in the ileum, compared with the control treatments. The probiotics did not affect the pH and the concentrations of short chain fatty acids (SCFA) and lactic acid in both the ileum and caeca.