Effect of increasing energy of diet and adding acetic acid on the performance and intestinal microflora of broilers

This study was conducted to evaluate the effect of acetic acid and diet energy on productive performance and intestinal microflora in 216 day-old broiler chicks. Chicks were divided to 2 parts and each part was split into 9 groups (12 birds) after six days. The first and second parts of chicks were fed by control (N) and high energy (H) diet, respectively. Each of the amounts of 0 (A0), 0.7(A0.7) and 1.4 (A1.4) acetic acid were added to diets of three groups of both parts in 3 replicates. A bird of each group in the day 18, 28 and 38 was slaughtered and its ileosecal contents were picked. CFU/g of Coliforms, E. coli and lactobacillus of samples were determined. The results showed that the lowest feed conversion ratio was achieved by 1.4% acetic acid (P<0.05). There was intraction effect of time and acetic acid on CFU/g of Coliforms and E. coli (P<0.05). On day 38, CFU/g of Coliforms obtained by 0.7 and 1.4 % acetic acid was lower than 0% acetic acid (P<0.05). CFU/g of E. coli with 0.7 % acetic acid, achieved on day 28 was higher than on day 38 (P<0.05). The lowest CFU/g of lactobacillus was obtained with 0% acetic acid (P<0.05). Conclusion, the addition of acetic acid up to 1.4% to diet of broilers can improve feed conversion ratio, enhance the growth of lactobacilli and prevent the growth of Coliforms and E. coli in the digestive contents.