Expression profiles of key transcription factors involved in lipid metabolism in Beijing-You chickens.

Intramuscular fat (IMF) is a crucial factor for the meat quality of chickens. With the aim of studying the molecular mechanisms underlying IMF deposition in chickens, the expression profiles of five candidate transcription factors involved in lipid metabolism in several tissues were examined in Beijing-You (BJY) chickens at five ages (0, 4, 8, 14 and 20 wk). Results showed that accumulation of IMF in breast (IMFbr), thigh (IMFth) and abdominal fat weight increased significantly (P<0.01) after 8 wk. Accumulation of both IMFbr and IMFth from 8 to 14 wk exceeded that from 14 to 20 wk; IMFth was 4-7 times of IMFbr. As for the expression profiles of key transcription factors: 1) expression of C/EBPα and PPARγ in abdominal fat was significantly higher than that in breast and thigh muscles at all ages. The expression of C/EBPα was positively correlated with PPARγ in both breast and thigh muscles, which indicated that both C/EBPα and PPARγ promoted fat deposition and might act through a unified pathway; 2) the expression of SREBP-1 in 0, 4, and 8 wk in thigh muscle was significantly higher than that in breast; 3) expression of C/EBPβ at 4 and 8 wk was significantly higher than that at 14 and 20 wk; and it was positively correlated with IMFth and IMFbr from 0 to 8 wk; 4) expression of PPARα in breast and thigh muscles was significantly higher than that in abdominal fat. Taken together, all five transcription factors studied play roles in lipid metabolism in chickens with C/EBPα and PPARγ being important effectors.