Effects of Phytosterols on Growth Performance and Fat Metabolism in Broilers

The purpose of this study was to investigate the effects of diet supplemented with different levels of phytosterols (PS) on growth performance and lipid metabolism in broilers. A total of four hundred 1-day-old chicks (female: male =1:1) were randomly assigned into 4 treatments, each of which replicated 5 times with 20 chicks per replicate. Birds were fed with a basal diet without any additive (control), or supplemented with PS at 30, 40, or 50mg/kg for 42 d. The results showed that PS had no significant (P>0.05) effect on growth performance during the whole experimental period of 1 to 42d of age. The highest levels of serum free fatty acid were found in diets supplemented with PS at 40mg/kg and 50 mg/kg in female and male chickens, respectively (P<0.05). PS had no significant influence (P<0.05) on the serum triglycerides compared with the controls in chickens. Serum fatty acid synthetase was significantly decreased (P<0.05) in all chickens supplemented with PS compared with the control. In addition, hepatic fatty acid synthase and sterol regulatory element-binding transcription factor 1c mRNA expressions in the 40 mg/kg and 50mg/kg PS treatments were found to be lower (P<0.05) than those in other treatments. It is concluded that PS, as feed additives, had a positive effect on lipolysis by inhibiting the enzymes related to lipolysis. Diets supplemented with 40mg/kg and 50mg/kg of PS had a better effect in female than in male chickens, respectively.