There is a real concern in broiler chicken industry to reduce the fat content of it ? s products. Therefore, reduction of fat in poultry with dietary or geneticis manipulations is considered. The objective of this study was to investigate the effects of different dietary fat sources including soybean oil (SO), poultry grease (PG) and yellow grease (YG) used as fat source and sex effect on expression of peroxisome proliferator activated receptor gamma, a major regulator of differentiation and proliferation in adipose tissue, and performance. Source of the fat had no effect on body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR). Level of fat had no effect on body weight gain but feed intake significantly decreased at high level of fat and feed conversion ratio was improved at high fat diet. Sex has significant effect on body weight gain, feed intake and feed conversion ratio and female broilers had lower body weight gain, feed intake than males. Abdominal fat was dissected and collected in -80?C. Total RNA was extracted with RNX reagent from abdominal fat in 49d. Semi-quantitative reverse transcription feed conversion ratio was used to show difference of expression of peroxisome proliferator activated receptor gamma. Results showed that dietary fatty acid profile and sexual hormone can affect expression of peroxisome proliferator activated receptor gamma and development of broiler abdominal fat. It might be concluded:1- dietary fat does not affect body weight gain, feed intake and feed conversion ratio, 2- diet of poultry grease and soybean oil might have major effect on expression of peroxisome proliferator activated receptor gamma, 3- poly unsaturated fatty acid of soybean oil and long carbon chain of poultry grease have a main effect on expression of peroxisome proliferator activated receptor gamma, 4- female broiler are more affected by expression of peroxisome proliferator activated receptor gamma than male because estrogen is an effector for peroxisome proliferator activated receptor gamma. Therefore, dietary fatty acid profile and sexual hormone can affect on development of broiler abdominal fat.
