The response of broiler chicks to dietary supplementation with a probiotic, acidifiers blend, and their combination

Abstract

This study investigated the effect of a probiotic (Bacillus subtilis DSM 17299), blend of acidifiers, and their combination on the performance of broiler chicks. Two hundred and twenty unsexed one-day-old broilers (Ross 308) were randomly distributed into four groups (55 birds per group divided into 5 replicates) as 2X2 factorial arrangement including two factors, probiotic and blend of acidifiers, each of which had two levels: yes and no. Performance was determined weekly. Haemagglutination test was performed on blood samples taken on days 28 and 42 after the birds were injected twice (days 14 and 28) with 10% suspension of sheep red blood cells (SRBC). On day 42, tissue samples taken from the duodenum, jejunum and ileum were prepared for histology via scanning electron microscopy. During the first three weeks, dietary addition of probiotic significantly (p<0.05) increased body weight gain (BWG) while acidifiers significantly lowered (p<0.01) feed conversion ratio (FCR). Antibody titer against SRBC increased remarkably (p<0.01) 15 days post the first injection when probiotic was administered. The probiotic also increased (p<0.01) the number of the duodenal goblet cells, and the density of jejunal and ileal villi. Overall, the supplementation of probiotic or acidifiers enhanced the growth performance of broiler chicks, mainly during the first three weeks of age. The probiotic also improved the immune response and intestinal morphology of broilers. However, there was no evidence of synergy when probiotic and acidifiers were co-administered.