Comparison of Broiler Performance and Carcass Parameters When Fed Diets Containing a Probiotic, an Organic Acid or Antibiotic Growth Promoter

摘要

This study was conducted to compare the broiler performance and carcass measurements fed diets containing a probiotic and an organic acid with those fed a diet containing antibiotic. In a completely randomized design, 320 commercial broilers were assigned to four dietary treatments. A control negative diet was prepared based on NRC recommendations. For preparing other diets, control diet was supplemented with a probiotic, propionic acid and an antibiotic (positive control) at the levels of 0.1, 2 and 1 g kg^-1 of diet, respectively. Metabolic body weight and feed intake were recorded on days 14, 28 and 42. At the day 43, one male chicken from each pen was randomly selected and killed for determining the carcass parameters. Metabolic weight gain just was significantly increased during the first 2 week by propionic acid. The birds fed probiotic and propionic acid, either significantly or numerically, had better feed efficiency and lower metabolic feed intake than negative control. Thigh, breast, abdominal fat and carcass yield s were unaffected by probiotic and propionic acid compared to negative control birds. No significant differences were observed in viability index among experimental groups. Although there were significant differences in performance index among the negative control group and those supplemented by propionic acid and probiotic groups during the first and the second 2 week, this difference just remained significant for propionic acid during the second 2 week. In conclusion, probiotic and especially propionic acid have potential to be used as suitable alternatives to antibiotic growth promoters in starter phase of broilers nutrition.