| Salmonella is a common pathogenic bacteria in poultry production,which is pernicious to broiler health.Salmonella infection has been a principal challenge for the broiler industry in the post-antibiotic era.The aim of this study is to investigate the effects of Brevibacillus laterosporus texasporus culture(BT)on growth,immunity and blood biochemical parameters of broilers and also to determine whether Brevibacillus laterosporus texasporus culture has a potential to act as a probiotic additive within broiler diets.300 one-day-old male Arbor Acres broilers chickens were randomly assigned to 5 treatments with 6 replications(10 individuals each replicate).The treatments included a positive control(PC)without Salmonella Pullorum challenge and fed the basal diet,a negative control(NC)challenged by Salmonella Pullorum and fed the basal diet,and other three treatments challenged by Salmonella Pullorum per os and fed three different experimental diets,which were prepared by adding 10 mg/kg kitasamycin as antibiotics growth promotor(AGP),50 mg/kg BT(BT50),or 100 mg/kg BT(BT100)in the basal diet.The birds challenged was infected with Salmonella Pullorum per os twice at 7 and 8 day-aged.The results showed that in the starter period,Salmonella infection retarded the growth rate of broilers significantly.AGP and 100 mg/kg BT could partly compensate the adverse effect of Salmonella.However,No significant effect of Salmonella and AGP or BT was found in finiser period.Salmonella inhibited serum IgM one day after challenge significantly and increased it 12 days after challenge(P<0.05).AGP and 100 mg/kg BT could correct the change of IgM.Salmonella also increase LPS level and monoamine oxidase activity level at 21 day-aged.Addition of AGP and BT decreased them to some extent.Liver histopathological anlysis indicated that the NC and BT50 had more serious abnormal liver tissue lesion while AGP and BT100 had less lesion.These findings suggested that BT could protect chickens from the adverse impacts of Salmonella infection and it can be used as a feed additive to substitute antibiotics for broiler chickens. |
