ABSTRACT Heat stress induces oxidative stress, and reduces body antioxidant metabolite levels, which can affect poultry production performance. Dietary antioxidants protect birds against the adverse effects of heat stress. The effects of increasing concentrations of dietary curcumin on the antioxidant parameters of layers maintained under high-temperature conditions for nine weeks were evaluated. Roman laying hens (n = 336, 22 weeks old, 1420 g BW) were divided into three treatment groups. The first group served as a thermoneutral control (kept at 25 ± 1 °C). The second group was exposed to high temperatures (32 ± 1 °C, 6 h/d), given a basal diet. The third group was further divided into five treatment groups (100, 150, 200, 250, 300 mg/kg Curcumin) fed a basal diet (treatments H1, H2, H3, H4, H5) under high temperatures conditions (32 ± 1 °C, 6 hours/day). As a result of this study, total superoxide dismutase activity was significantly higher in H2 and H3 groups, and total antioxidant capacity was higher in H2, H3, and H5 groups. Catalase and glutathione peroxidase activity was significantly higher in the H3 group. Malondialdehyde concentration was lowered in curcumin supplemented hens compared with control groups hens. Laying hens in all curcumin treatment groups had slightly higher activities of CAT, SOD, GSH-Px, and T-AOC in the liver, heart, and lungs, compared with heat stressed control group. It was concluded that dietary curcumin given to laying hens under heat stress may enhance their antioxidant status, and alleviate the detrimental effects of stressful environmental conditions.

ABSTRACT The effects of oxidative stress induced by high temperature on the cell viability, proliferation, apoptosis and oxidative status of chicken embryonic fibroblasts (CEF) were analyzed. The viability, proliferation, apoptotic and anti-oxidative status were measured after incubating CEF at the temperatures of 37ºC (control) and 40-44ºC (experimental groups) for 6,12 and 24 hours. The results showed that at high temperature (42-43ºC), the viability of CEF cells decreased after 6, 12 and 24 h of incubation, but the difference was significant only at 43ºC. Cell proliferation was significantly reduced at 44oC/6h. The apoptotic rate of CEF cells was increased following heat treatments in a time-dependent manner. ROS formation increased with increasing temperature, but the difference was only significant at 44ºC/6,12h. Heat stress did not significantly affect the superoxide dismutase (SOD) activity. CAT activity was significantly decreased at 43ºC/24h and 44ºC/12 and 24h. Malondialdehyde (MDA) formation was significantly increased at 43ºC/12h and 44ºC/12 and 24h. In conclusion, heat stress induced the oxidative stress, decreasing the viability, proliferation and anti-oxidative response of CEF cells.

ABSTRACT To study the development rules of Chinese native geese, two breeds, Shitou and Sichuan White geese were analyzed from 0 to 12 weeks of age. The growth curves were fitted with commonly used four kinds of nonlinear models (Logistic, Gompertz, Von Bertalanffy and Richards). The results showed that the growth curves were appropriately fitted with all four models but the Logistic and Richards both had the best fitting with growth curve (R2>0.99). Analyzing the fitting parameters of the Logistic and Richards, we found that male Shitou had the highest adult body weight while Sichuan White female had the lowest weight. In Shitou breed, Shape parameter Predicted with Richards model was corresponded with Gompertz curve, while in Sichuan breed it was in between Gompertz and Bertalanffy. Growth parameters predicted with Logistic model was much more closed to observed value as compared others. So overall logistic was the best model to analyze the growth curve in Chinese native goose and Shitou goose had excellent growth performance when compared to Sichuan White.