Effect of quercetin (flavonoid) supplementation on growth performance, meat stability, and immunological response in broiler chickens

This study was conducted to determine the effect of quercetin supplementation on growth performance, meat stability, excreta gas emission, and immunological response in broiler chickens. A total of 640 broiler chickens were randomly assigned to 1 of the 4 treatments (10 replicates per treatment with 18 chickens per pen). Dietary treatments: basal diet contained 0, 250, 500, and 1,000 mg quercetin/kg. The chronic heat stress condition was maintained (32 degrees C) for 24 h from the fourth day of the study. Growth performance was assessed on d 0, 7, 21, and 35, whereas all other response criteria were determined on d 35. Overall, a quadratic effect of quercetin supplementation on body weight gain (BWG) was observed when quercetin supplementation was increased (P < 0.05). And these responses were maximized in the broiler chickens fed diet with 250 mg quercetin/kg. There was a linear and quadratic effect of quercetin supplementation on Lactobacillus counts (P < 0.05). As the dietary supplementation of quercetin increased, the content of total superoxide dismutase (T-SOD) and total antioxidant capacity (T-AOC) linearly increased (P < 0.05), while the malondialdehyde (MDA) concentration linearly reduced in breast muscle (P < 0.05). There was a linear decrease in abdominal fat content when quercetin supplementation was increased (P < 0.05). The concentration of tumor necrosis factor-alpha (TNF-alpha) linearly increased by adding an increasing dosage of quercetin in the diet (P < 0.05). In conclusion, the addition of quercetin in the diet could improve BWG which reflected a beneficial effect of quercetin for growth performance. Increasing dose range from 0 to 1,000 mg quercetin/kg could linearly increase the content of T-AOC and T-SOD, and reduce the concentration of MDA, which reflected that the increased quercetin supplementation can enhance meat stability. Furthermore, supplementation of quercetin could increase the level of TNF-alpha, which indicated the ability of quercetin to enhance the immune capacity of broiler chickens.