CECT 5940 improves performance and gut function in broilers fed different levels of protein and/or under necrotic enteritis challenge.

Two studies were conducted to investigate the effect of CECT 5940 (BA) as a probiotic on growth performance, amino acid digestibility and bacteria population in broiler chickens under a subclinical necrotic enteritis (NE) challenge and/or fed diets with different levels of crude protein (CP). Both studies consisted of a 2 × 2 factorial arrangement of treatments with 480 Ross 308 mix-sexed broiler chickens. In study 1, treatments included 1) NE challenge (+/-), and 2) BA (1.0 × 10 CFU/g of feed) supplementation (+/-). In study 2, all birds were under NE challenge, and treatments were 1) CP level (Standard/Reduced [2% less than standard]) and 2) BA (1.0 × 10 CFU/g of feed) supplementation (+/-). After inducing NE infection, blood samples were taken on d 16 for uric acid evaluation, and cecal samples were collected for bacterial enumeration. In both studies, ileal digesta was collected on d 35 for nutrient digestibility evaluation. In study 1, the NE challenge reduced body weight gain (BWG), supressed feed conversion ratio (FCR) and serum uric acid levels ( < 0.001). Supplementation of BA increased BWG ( < 0.001) and reduced FCR ( = 0.043) across dietary treatments, regardless of challenge. ( = 0.030) and ( = 0.029) genomic DNA copy numbers and concentration of butyrate ( = 0.017) were higher in birds fed the diets supplemented with BA. In study 2, reduced protein (RCP) diets decreased BWG ( = 0.010) and uric acid levels in serum ( < 0.001). Supplementation of BA improved BWG ( = 0.001) and FCR ( = 0.005) and increased numbers ( = 0.018) and butyrate concentration ( = 0.033) in the ceca, regardless of dietary CP level. Further, addition of BA reduced numbers only in birds fed with RCP diets ( = 0.039). At d 35, BA supplemented diets showed higher apparent ileal digestibility of cystine ( = 0.013), valine ( = 0.020), and lysine ( = 0.014). In conclusion, this study suggests positive effects of BA supplementation in broiler diets via modulating gut microflora and improving nutrient uptake.