LAUSR

Probiotics (useful microorganisms) are colonized in intestine of animal and birds and provide useful effects on performance and immune of the animals. This study describes a high throughput screening and characterization of spore-forming bacteria from Iranian poultry farms with the aim to identify potential probiotic native Bacillus spp . and determine its effects on growth performance, hemato-biochemical parameters, immunity, intestinal microflora, morphology and MUC2 gene expression of broiler chickens. A total of 300 one-day-old female Ross 308 broilers (42.6 ± 0.6 g) were used in a 6-wk study. Broilers were randomly allotted to 1 of 3 dietary treatments consisting of 4 replicate cages with 25 broilers each: 1- Control (Corn-soy-based diet: C), 2- C + 200 g/ton of the GalliPro® ( Bacillus subtilis DSM 17299, 4×10 9 CFU/g, as positive control group: PC), 3- C + 200 g/ton of the native probiotic ( B. tequilensis K03, 4×10 9 CFU/g: NP) identified in this study. During the experiment parameters were measured weekly. The results revealed that dietary supplemented with NP and PC improved feed conversion ratio (FCR) and increased body weight (BW), carcass and breast meat yield compared with C (P < 0.05). Also, lymphocytes level, antibody titers against Newcastle diseases virus (NDV) and infectious bronchitis virus (IBV) of vaccinated birds was increased, while serum triglycerides, total cholesterol levels and abdominal fat of birds fed NP and PC were decreased in compare to the C (P < 0.05). The villus height, the relative expression of MUC2 gene and Bacillus spp . populations were increased, while E. coli was significantly decreased in the ileum content of treated groups (P < 0.05). These results indicate that the identified native B.tequilensis K03 strain can improve immunity and broiler performance by modifying intestinal microflora and morphology. Studied native probiotic Bacillus tequilensis K03 has useful effects on health status as a result it can be used as poultry feed supplement.