The effect of antibiotic-free diets on the immune system, morphology and intestinal microbial flora of broiler chickens under intensive rearing

Abstract

Introduction: This experiment was conducted to investigate the effect antibiotic-free diets on the immune system, morphology and intestinal microbial flora of broiler chickens under intensive rearing.

Materials & Methods: This experiment was conducted using 250 broiler chickens of Ross 308 strain in a completely randomized design with 4 treatments and 4 replications. Experimental treatments include: treatment 1- normal density (10 chickens per square meter) and basic diet, 2- high density (15 chickens per square meter) and basic diet, 3- normal density and basic diet without oxytetracycline antibiotic (250 grams per ton of feed) and 4- high density and basic ration plus oxytetracycline antibiotic (250 grams per ton of feed).

Results: The results showed that the increase in herd density caused a decrease in the ileum lactobacillus population, length and width, malondialdehyde and alanine aminotransferase in plasma (P<0.01). In contrast, the addition of antibiotics to the diet of broilers under crowded conditions led to the compensation of injuries caused by crowding stress, and improved the immune status of broilers.

Conclusion: In general, based on the results of this experiment, the removal of antibiotics from the diet of broiler chickens raised in dense conditions is not reasonable and reduces the immunological and morphological parameters of broiler chickens.