Effect of feeding diets containing a probiotic or antibiotic on broiler performance, intestinal mucosa-associated avian pathogenic E. coli and litter water-soluble phosphorus

Abstract

SummaryThe aim of the present experiment was to examine the influence of feeding diets containing a probiotic containing three Bacillus subtilis strains or zinc bacitracin (BMD) on bird performance, intestinal mucosa-associated avian pathogenic Escherichia coli (APEC), intestinal morphology and litter water-soluble phosphorus (WSP) of broilers fed corn-based diets. Three treatments were employed, either a control diet; the control diet supplemented with probiotic at 7.5 × 104 colony forming units (cfu) /g of feed or the supplemented with BMD (50g/tonne feed). Broiler starter and finisher diets, based on corn and soybean meal, were formulated and fed ad libitum to seven pens of 50 male broilers per treatment from days 1 to 42. During the 1-35 d periods, feed intake and weight gain were not influenced (P > 0.05) by dietary treatments, but probiotic supplementation improved (P < 0.05) 35-d FCR compared to the control and BMD-supplemented diets (1.395, 1.447 and 1.484, respectively). During the 1-42d period, feed intake and weight gain were not influenced (P > 0.05) by dietary treatments. However, probiotic improved (P = 0.05) and BMD tended (P = 0.07) to improve FCR compared to control diet. Villus height and crypt depth in the duodenum and jejunum were not influenced (P > 0.05) by dietary treatment. The number of mucosa-associated APEC was not influenced (P > 0.05) by dietary treatments. Probiotic and BMD supplementation had no effect (P > 0.05) on litter total phosphorus. However, BMD reduced (P < 0.05) litter WSP compared to control and probiotic supplemented diet. In conclusion, probiotic supplementation had no effect on intestinal morphology or WSP but improved broiler performance and can be used as an alternative to antibiotic growth promoters.