An evaluation of gallic acid supplementation to corn-soybean-gluten meal-based diet in broilers

Gallic acid (GA) is an endogenous plant polyphenol found in fruits, nuts, and plants that has antioxidant, antimicrobial, and growth-promoting effects. This study aimed to assess the effect of graded doses of dietary supplemented GA on growth performance, nutrient retention, fecal score, footpad lesion score, tibia ash, and meat quality of broilers. A total of 576 one-day-old Ross 308 male broiler chicks with an average initial body weight of 41 ± 0.5 g were used in a 32 d feeding trial. Broilers were sorted into 4 treatments, 8 replications per treatment, and 18 birds per cage. Dietary treatments consisted of corn-soybean-gluten meal-based basal diet and the basal diet supplemented with 0, 0.02, 0.04, and 0.06% of GA. Feeding broilers with a graded doses of GA increased body weight gain (BWG) (P < 0.05) and feed intake (P < 0.05) linearly on phase 2 (d 9-21). Additionally, the nutrient digestibility of dry matter (P < 0.05) and energy (P < 0.05) was increased linearly by including a rising level of GA in the broiler diet. However, the excreta score, footpad lesion score, tibia ash, and meat quality presented no significant effect (P > 0.05) except meat color of yellowness. Adding GA at increasing doses to broiler diets increased growth efficiency and nutritional absorption without affecting excreta score, footpad lesion score, tibia ash, and meat quality. In conclusion, the inclusion of graded levels of GA to corn-soybean-gluten meal-based diet presented dose-dependent improvement in growth performance and nutrient digestibility of broilers.