Relationship between abdominal fat content and avian uncoupling protein gene expression in skeletal muscle of Japanese quail Coturnix japonica.

1. The genetic architecture of the avian uncoupling protein (avUCP) was investigated and the relationship between avUCP gene expression and the amount of abdominal fat of Japanese quail was determined by quantitative real-time PCR. 2. The Japanese quail avUCP gene consists of six exons and five introns. Sequences of nucleotides and amino acids were 94·6% and 86·0% identical to those of the chicken avUCP gene, and phylogenetic analysis showed that the Japanese quail avUCP gene consists of the same clusters as the chicken and turkey avUCP. 3. Expression of the avUCP gene was significantly higher in the Pectoralis major (1·28 ± 0·24) than in the Biceps femoris (0·63 ± 0·14). 4. A positive correlation coefficient between the avUCP gene expression in the Pectoralis major and Biceps femoris was observed (r = 0·79, P = 0·02), whereas a negative correlation coefficient was observed between the abdominal fat percentage (AFP) and gene expression in both the Pectoralis major (r = -0·82, P = 0·01) and Biceps femoris (r = -0·61, P = 0·11). 5. The avUCP gene was associated with the accumulation of abdominal fat in Japanese quail and it was concluded that modulation of avUCP gene expression could be utilised to control abdominal fat accumulation in poultry.