Dietary curcumin supplementation relieves hydrogen peroxide-induced testicular injury by antioxidant and anti-apoptotic effects in roosters

This study was aimed to investigate the effects of dietary curcumin supplementation on the hydrogen peroxide (H2O2)-induced testicular oxidative damage in breeder roosters. Thirty-two 20-week roosters were randomly divided into four groups: (1) basal diet (CON); (2) basal diet with H2O2 challenge (H2O2); (3) basal diet with 200 mg/kg curcumin (CUR); (4) basal diet with 200 mg/kg curcumin and H2O2 challenge (CUR + H2O2). The trial lasted for 8 weeks, H2O2 challenged groups got an intraperitoneal injection of H2O2 at the 50 and 53 days, while the CON and CUR groups received an injection of saline. The results showed that dietary curcumin supplementation significantly decreased abnormal sperm rates in the semen, notably improved seminiferous tubules, increased testis scores, and serum testosterone levels. Curcumin supplementation could also ameliorate the redox damage caused by H2O2, by enhancing the capacities of antioxidant enzymes (CAT, GSH-Px, SOD, and T-AOC), and reducing MDA levels. In addition, curcumin normalized the H2O2-induced negative effects, which included downregulations in spermatogenesis-related genes (STAR, HSD3-β1, SYCP3, AKT1) and antioxidant genes (HMOX-1, NQO-1), reduced protein expressions of Nrf2, PCNA, and Bcl-2, and increased protein expressions of Caspase 3 and Bax. Moreover, H2O2-induced decreased mRNA expressions of EIF2AK3, Caspase3, and BCL-2 were all reversed by dietary curcumin supplementation. In summary, dietary curcumin supplementation could relieve H2O2-induced oxidative damage and reproduction decline through the Nrf2 signaling pathway and anti-apoptotic effects in roosters.