PSIX-9 Dietary β-sitosterol improves immunity and antioxidant status in broilers

Abstract

Abstract The application effects of phytosterols on poultry production have been reported. However, due to the mixed compositions, it is difficult to explain their action mode and physiological functions. β-sitosterol, the most abundant phytosterol, is naturally widespread in plant products. Information, however, is scarce in terms of effects of β-sitosterol on broilers. This research therefore investigated effects of dietary β-sitosterol with different levels on immunity and antioxidant capacity in broilers. Two hundred and forty one-day-old chicks were randomly allocated into five treatments of six replicates. Chickens in the five groups were fed a basal diet supplemented with 0 (control group), 40, 60, 80, and 100 mg/kg β-sitesterol for 42 days, respectively. Data were analyzed by one-way analysis of variance. Polynomial contrasts were used to test the linear and quadratic response to β-sitosterol levels. Difference among groups was evaluated using Tukey’s test, which was considered significant if P < 0.05. Dietary β-sitosterol linearly increased (P < 0.05) contents of serum immunoglobulin G and hepatic glutathione, activities of serum superoxide dismutase and catalase, whereas linearly decreased (P < 0.05) concentrations of serum tumor necrosis factor α and hepatic malondialdehyde. Serum interleukin 1β level was linearly and quadratically reduced by β-sitosterol inclusion (P < 0.05). Compared with the control group, dietary β-sitosterol with higher levels than 60 mg/kg increased concentrations of serum immunoglobulin G and hepatic glutathione, activities of serum superoxide dismutase and catalase (P < 0.05), whereas decreased serum tumor necrosis factor α content (P < 0.05). Its dosages higher than 40 mg/kg reduced serum interleukin 1β content (P < 0.05), and 100 mg/kg of which lowered hepatic malondialdehyde concentration (P < 0.05). The results indicated that dietary β-sitosterol could improve immunity and antioxidant ability in broilers. Also, a level of 80 mg/kg β-sitosterol supplementation was recommended into broiler diet.