Effects of different feed additives and antibiotic growth promoter on the immune response, tibia bone characteristics, meat quality and growth performance of Ross 308 broiler chickens

The effects of different feed additives as antibiotic replacement on the growth performance, immune response, tibia characteristics and meat quality of broilers were investigated. In this experiment, 540 one-day-old male broiler chickens of Ross 308 strain were randomly distributed into 6 treatments with 6 replicates per each. The experimental treatments were 1) a control group (corn-soybean meal diet), 2) control group + 0.25 g/kg antibiotic as growth promoter (Lincomycin), 3) control group + 1 g/kg herbal extract (contains garlic, thyme, turmeric, lemon balm), 4) control group + 3 g/kg medium chain fatty acids (contains a mixture of caproic, caprylic, capric, and lauric acids), 5) control group + a mix of 1.5 g/kg prebiotic (MHF-Y) and 0.2 g probiotic (Lactofeed) and 6) 1 ml/L essential oils in drinking water (contains ferula gummosa, eucalyptus, clove, peppermint, thyme, fennel, ajwain and satureja). Feed conversion ratio and body weight gain were improved in broilers which received feed additives compared to control group throughout the experiment. Hetrophil and lymphocyte and antibody titers, and tibia characteristics were not affected by the experimental treatments. However, the highest relative weight of spleen and total ash of tibia observed in broilers which received medium chain fatty acids. experimental treatments had no effect on the meat quality. It can be concluded that feed additives may improved growth performance and some of the immune and tibia traits in broiler chickens