Changes in peroxisome proliferator-activated receptor gamma gene expression of chicken abdominal adipose tissue with different age, sex and genotype

Peroxisome proliferatior-activated receptor gamma (PPAR gamma) is a transcription factor that regulates adipocyte differentiation, and the activation of PPAR gamma increases fat deposition in growing chickens. The aim of the present study was to investigate whether the levels of PPAR gamma gene expression were related to fat pad weight in abdominal adipose tissue in growing chickens with different genotype and sex. Body weight and abdominal adipose tissue weight in broiler chickens (Ross strain) were higher than the other genotypes (Road Island Red, White Leghorn, and Japanese native poultry (Tsushima)) at 3 and 5 weeks of age. PPAR gamma mRNA expression in abdominal adipose tissue tended to increase with age, as evidenced by higher expression levels at 5 weeks than at 1 week of age in all sex and genotype of chickens. In broiler chickens, the PPAR gamma expressions were significantly higher than the other genotypes. PPAR gamma mRNA expression levels in abdominal adipose tissue of female chickens rapidly increased at 3 weeks, and were unchanged until 5 weeks, while those in male chickens gradually increased until 5 weeks. In addition, abdominal adipose tissue weight was correlated with PPAR gamma expression levels. These results demonstrated that PPAR gamma gene expression is a useful marker of fat deposition in chickens, suggesting that PPAR gamma is a key factor of fat accumulation in chicken abdominal fat pad.