De novo lipogenesis in the liver and adipose tissues of ducks during early growth stages after hatching.

In vivo de novo lipogenesis (DNL) in the liver and adipose tissues of ducks during early developmental stages after hatching has not previously been investigated. In this study, female Peking ducks (Anas platyrhynchos) at weeks 1 to 8 post-hatching were selected for experimentation. We measured the mRNA levels of 6 DNL-related genes in the duck liver, subcutaneous adipose tissue and abdominal adipose tissue by real-time PCR during the 8 weeks. Correlations of the plasma triacylglycerol (TG) and very low density lipoprotein (VLDL) concentrations with fat deposition at these sites were also detected during growth. Our results showed that fat content was highest in the subcutaneous adipose tissue and lowest in the liver during the growth period we studied. Additionally, plasma VLDL and TG were significantly associated with lipid content in adipose tissue (P<0.05), but not in the liver. Lastly, in the growing birds, the expression levels of lipogenic genes (with the exceptions SREBP-1c and SCD1) were much higher in the liver than in the adipose tissues, and the maximal expression levels of these genes occurred at week 4 or 5 at these sites. These findings indicated that the main site of DNL is always the liver in post-hatching ducks, and adipose tissues are of little importance for DNL. Taken together, our results suggested that the plasma lipoproteins contribute greatly to fat deposition in adipose tissues originating from hepatic lipogenesis.