Abstract

The present study was conducted to evaluate the influence of physical form of organic acid and antibiotics on the performance of broiler chickens challenged with Salmonella typhimurium (S. typhimurium). Two hundred forty 1-d-old male broilers (Cobb 500) were equally distributed into 6 treatment groups with 10 blocks and 24 chicks each. The treatments were: group 1 (positive control, basal diet without any addition, non-medicated and unchallenged), group 2 (negative control, basal diet, non-medicated and challenged), group 3 (basal diet with 0.05 g antibiotic flavomycin /kg diet) and groups 4 and 5 (basal diet with 1 g of commercial mixture powder and coated of organic acids fumaric) and citric acids/kg diet), respectively. Group 6 is a blend coated of organic acids (fumaric and citric) and their ammonium salts 2.5 g/kg diet. At 16 days of age, using oral dose, birds were challenged with S. typhimurium (2×108 CFU/ml). Average body weight of group 3 and 5 was significantly increased (P < 0.05) at 21, 28 and 35 days of age and daily weight gain in the overall period was compared to other treatment groups. The highest value of daily feed intake was observed in dietary supplementation compared to the negative control (group 2), but group 2 had lower significant effect (P < 0.05) compared to the positive control (group 1) during the 15-21 days of age. However, supplementing diets with experimental groups had no significant effect (P < 0.05) on daily feed conversion ratio, during all periods. The results revealed that the supplementation of antibiotics and organic acids as coated capsules into the broiler diets might improve the performance in challenged broiler chicks with S. typhimurium.