The influence of the addition of thymol, tannic acid or gallic acid to broiler diet on growth performance, serum malondialdehyde value and cecal fermentation

An experiment was conducted to test the effects of different phenolic compounds on growth performance and cecal fermentation patterns in growing broiler chicken. Sixty Ross 308 chicken broilers were randomly divided into 4 dietary treatments. Each treatment had 3 replicates with 5 birds per replicate pen. Treatments differed in the supplement added to the feed: control (CON), 200 mg/kg of thymol (THY), 5 g/kg of tannic acid (TAN) and 5 g/kg of gallic acid (GAL). The inclusion of tannic acid improved final body weight. Feed utilization was improved in all experimental groups. The dietary inclusion of tannic acid and gallic acid significantly increased the concentrations of total SCFA concentration and acetic acid. Tannic acid decreased propionic acid molar ratio and cecal pH value. It was concluded that tannic acid and gallic acid supplementation around 5 g/kg could be beneficial for the fermentation processes in the caecum of broilers. Thymol addition at 200 mg/kg increases antioxidant capacity and does not negatively influence cecal fermentation.