Polyphenols improved the heat stress induced immune suppression in broilers

Heat stress adversely affects the performance, immunity, survivability and economics in broiler chickens. Polyphenols exhibits potent antioxidant, antimicrobial, anti-inflammatory activity and are expected to improve the immune response. In the present study day-old broiler chicks (n=180) were randomly allocated to three groups and reared for 42 days under hot-humid environment (Temp: 2944°C; RH: 69–80%). The first group was fed corn-soybean meal diet without polyphenol supplementation (Control), second group with 50 ppm (T1) and third groups with 100 ppm polyphenols (T2). The polyphenols were extracted from pomegranate peels using methanol as solvent. Incorporation of polyphenols improved the body weight in T1 and T2 group chicks as compared to control group. Polyphenols supplementation improved (P<0.05) the cellular immunity against intradermal PHA-P (100.00 vs 134.80, 126.41%) and humoral response against NDV vaccine (1.71 vs 1.93, 1.95). The mRNA expression of interleukin II (IL-2) in spleen was also significantly up-regulated in supplemented groups. There was a dose dependent reduction in the heat stress induced corticosterone concentration in plasma of polyphenol supplemented birds. From the study it could be concluded that supplementation of polyphenols @ 50 ppm improved the growth and cell mediated type of immune response in heat stressed broilers.