Effects of tannic acid on performance and fatty acid composition of breast muscle in broiler chickens under heat stress

One hundred twenty day-old broiler chicks (Cobb 500) were randomly assigned into 4 treatment groups to investigate the effects of tannic acid supplementation (TA) on fatty acid composition in breast muscle of broilers under chronic heat exposure conditions. Five pen replicates of 6 chicks each were assigned to each of the following 4 dietary treatments: i) basal diet containing no TA at 25 degrees C (CL); ii) basal diet containing no TA at 35 degrees C (CH); iii) basal diet supplemented with 1% TA at 25 degrees C (TL); and iv) basal diet supplemented with 1% TA at 35 degrees C (TH). At the end of the 5-week experiment, breast muscle samples were collected to examine the fatty acid composition. Results showed that temperature, TA and their interaction effect significantly decreased body weight gain and feed intake. In addition, feed conversion ratio (FCR) significantly increased under high temperature, and addition of TA under high temperature did not improve the FCR. The effects of temperature, TA and their interaction on the saturated and unsaturated fatty acids were not significant (P>0.05). However, monounsaturated fatty acids significantly reduced by adding TA to the diet. Generally, TA improved the fatty acid profile of breast muscle of broilers under heat stress in comparison to the heat stressed chickens, which did not receive TA. Hence, it seems that dietary TA supplementation can be applied as a biological antioxidant for poultry nutrition in hot climatic conditions.