Evaluating the effects of garlic (Allium sativum) as a feed additive on the growth performance and immune response in broiler chickens

Abstract

In a quest to find affordable, antibiotics free and readily available means of increasing broiler meat productivity, a number of natural feed additives have been tested and suggested. Garlic (Allium sativum) has emerged as a preferable alternative to synthetic feed additives. The aim of this study was to assess the effect of garlic as a feed additive on feed intake, weight gain, feed conversion ratio, and immune response. 300-day-old chicks were acclimatized for 2 weeks and then randomly assigned to 5 treatments (0.00%, 0.25%, 0.50%, 0.75%, and 1.00% garlic inclusion levels) with replicates. Mean weekly feed intake, weight gain, feed conversion ratio, and differential leucocyte counts (lymphocytes, heterophils, basophils, eosinophils, and monocytes) were analyzed for treatment effects. There were significant differences among the means across all treatments for all dependent variables except mean weekly body weight gain at 2 weeks. Garlic supplementation significantly influenced body weight from three to six weeks of age, with the control group (0.00%) consistently exhibiting the lowest body weight. At six weeks, body weight was highest at 0.75%, followed by 1.00%, 0.50%, and 0.25% garlic inclusion levels, demonstrating the positive impact of dietary garlic on growth performance. It was also observed that garlic supplementation led to increases in the basophil and monocyte counts, suggesting a bolstered immune system.