The Effect of Probiotic on Performance and Immunity Parameters of Broilers

This experiment was carried out to investigate the effect of probiotic on performance and immunity parameters of broilers. This research was done in a completely randomized design with four treatments and four replications (14 chickens in each). A total of 224 Ross 308 one-day old broiler chicks were used. The rations supplied on the basis of NRC recommendations in periods of startrer, grower and finisher. At the end of experiment, one broiler from each pen with similar weight to mean weight of that pen was slaughtered to determine carcass characteristics. For blood collection, 3 broilers from each pen were selected and blood samples were collected in two stages of 28 and 35 days. The results showed that the body weight improved with the use of probiotic in periods of grower and finisher. Broilers fed with probiotic in periods of startrer, grower and finisher in comparison with the control group had a lower feed conversion ratio. The carcass yield, total gastrointestinal tract, pancreas weight and caeca length were significantly increased when probiotics were added in rations. Broilers fed with probiotic had lower abdominal fat (0.84) in comparison with the control group (1.8). In addition a significant decrease was observed in intestinal pH in broilers fed with probiotic. The use of probiotic significantly improved the titers of gumboro and newcastle in broilers. Therefore, it can be concluded that the supplementation of diet with probiotic has positive effects on performance and immune system of broilers.