In recent years, feed additives have been widely used for their positive effects of improving health status, productive performance, and carcass quality in both livestock and poultry. Numerous studies have highlighted the fact that a series of medicinal plants, in the form of powder, extracts, or essential oils, both as single compounds and mixed preparations, can be introduced into the feed of broiler chickens. They exhibit beneficial effects on both the intestinal microflora and digestibility of nutrients, aspects that are reflected in the quality of meat and eggs. Among them, garlic occupies a special place due to its broad spectrum of action and its availability for poultry farmers. The present study aims to evaluate the effects of supplementing the diet of broilers with garlic powder (Allium sativum) on their growth performance and the morphology of their intestine and liver. Twenty-four one-day-old ROS 308 male hybrids were randomly assigned to two groups, each group with two replications, of six individuals: the control group (LC), which was fed with the basic diet, and the experimental group (LGa), in whose diet 1% garlic powder was introduced. Food and water were provided ad libitum until the end of the experiment (42 days).

The obtained results show that supplementing the basic diet with 1% garlic powder in broilers had a significant effect on body weight, feed intake, and FCR (p<0.05), as well as on the studied histomorphometric parameters: the height, width, area, perimeter of the intestinal villi (p<0.01), and depth of the crypts (p<0.05).

In conclusion, supplementing the basic diet of broiler chickens with 1% garlic powder, from 1 to 42 days, improves growth performance and increases the absorptive surface of the intestinal villi, as well as implicitly increasing the absorption capacity of nutrients; these aspects prove that garlic can be considered a growth promoter.