Does the use of lactic acid as an antibiotic substitute in broiler diets affect growth, carcass traits, blood indices and intestinal microbiota?

The objective of the current study was to determine the impact of lactic acid (LAC) as an antibiotic alternative in broiler diets on growth performance, carcass traits, blood indices and intestinal microbial load. A total of 300 broiler chicks one day old (Ross 208) were allotted to five experimental groups in a complete randomized design experiment. Each group was subdivided into six replicates, each of ten unsexed chicks. The treatments were as follows: NC: negative control (basal diet); PC: positive control (basal diet + 0.5 g Colistin® antibiotic/kg diet); LAC2, LAC4, and LAC6: basal diet + 2, 4, and 6 cm3 lactic acid/kg diet, respectively. Results showed no significant effects of dietary treatments (antibiotic or lactic acid) on growth performance traits (body weight, BW; daily body weight gain, DBWG; feed intake, FI and feed conversion ratio, FCR) and carcass characteristics except for Thigh %. All blood biochemical traits were affected (p > 0.01) by dietary treatments. The highest values of blood total protein and albumin were found in birds of LAC2 group. Adding graded doses of LAC to broiler diets inhibited the activity of liver enzymes and reduced the concentration of blood urea. The positive effect of LAC supplementation excelled that of antibiotics regarding the antioxidant status parameters. The lowest pathogenic bacteria (E. coli and Salmonella) were recorded by LAC4 and LAC6 groups. It could be concluded that dietary supplementation of lactic acid did not significantly affect most growth performance traits. But its use could have beneficial impacts on blood parameters, oxidative status and intestinal microbial counts. Based on our results, the highest level (6 cm3 LAC/kg diet) is the recommended level for the best results.