Growth, carcass characteristics, immunocompetence and response to Escherichia coli of broilers fed diets with various levels of Probiotic

An experiment was conducted on three hundred and twenty broiler chicks to e valuate the influence of dietary supplementation of probiotic on immunocomp etence, response to E. coli, growth and carcass characteristics in broilers . The chicks were placed on one of the four dietary treatments. The dietary treatments were a basal diet (control), and three other diets which were s ame in composition as that of basal diet but supplemented with three levels of probiotic (Probiolac; 100 mg, 150 mg and 200 mg per kg diet). Supplementation of probiotic 100 mg per kg diet significantly improved the body weight gain (0-4 wks) but no difference was observed subsequently. Pro biotic supplementation of diet did not influence feed consumption or feed c onversion ratio. There was significantly higher antibody production in the 100 mg probiotic supplementation group at 10 days and 5 days of post inocul ation in response to SRBC antigen when injected at 14 days and 21 days of a ge respectively, compared to control. The birds fed probiotic were less sus ceptible to E. coli challenge compared to control, however no difference wa s observed in the weight of bursa and spleen due to probiotic supplementati on. Supplementation of probiotic had no influence on dressing percentage or weight of internal organs like liver; heart and gizzard.