effects of using a multi-strain probiotic on performance, immune responses and cecal microflora composition in broiler chickens reared under cyclic heat stress condition

this experiment was conducted to examine the effect of multi-strain probiotic (primalac) on performance, immune responses and cecal microflora in broiler chickens under cyclic heat stress condition. a total of 96 one-d-old mixed sex broiler chicks (ross 308) were weighed and randomly allocated to two treatment groups, each with 4 replicate pens of 12 chicks. the dietary treatments were basal diet (control) andcontrol +0.9 g primalac/kg diet. body weights of broilers were determined at d 1, 21 and 42, feed intake was determined at the same periods, and feed conversion ratio was calculated accordingly. the populations of lactobacilli spp and coliforms were enumerated in the cecum. antibody titers against newcastle, bronchitis, and gumboro were measured as immune responses at 28 d of age. as a result of this study, use of probiotic significantly(p