| Abstract:Peking duck belongs to the large meat duck, while Heiwu duck belongs to the lean meat duck. There are significant differences between the two species of duck about the growth development and fat deposition, the Peking duck grows faster with large fat accumulated in the subcutaneous adipose tissue compared to the Heiwu duck. In this research, Peking duck and Heiwu duck were used as experimental materials to investigate the differences of liver lipid metabolism and adipogenesis of the two species, which could provide certain references to explain the mechanisms of duck lipid metabolism and fat accumulation, as well as breeding the meat duck. The following experiments were conducted:comparing the differences of carcass traits and plasmid lipid metabolism related parameters of the two species during different growth stages, detecting the expression levels of key genes related with lipid synthesis such as FAS, ACC and DGAT2in liver, as well as the expression levels of PPARy, C/EBPa in leg adipose tissue, abdominal and subcutaneous adipose tissue. The main research results were listed as follows:1. During the stage of week4to16, live weights of Peking duck were much higher than Heiwu duck (P<0.05), while carcass weights of Peking duck were higher than Heiwu duck during week2to16(P<0.05). From week4to16, liver weights of Peking duck were significantly larger than that of Heiwu duck. Weights of abdominal and subcutaneous adipose tissues of Peking duck were obviously higher than that of Heiwu duck at week8and16, while the leg adipose tissue weights of Peking duck were lager than Heiwu duck from week4to16. Moreover, there was much more fat accumulated in subcutaneous adipose tissue of Peking duck compared with Heiwu duck.2.At20days of embryonic age, levels of plasma TC, LDL of Peking duck were significantly higher than that of Heiwu duck (P<0.05), but only the LDL levels were higher in Peking duck when ducks were hatched. When ducks were2weeks old after hatching, concentrations of TC were larger in Heiwu duck than Peking duck (P＜0.05)3.The expression levels of lipid synthesis related genes (FAS, ACC and DGAT2) in liver of the two species at week16were much higher than that of week8, in particular expression of ACC at week16was significantly higher than week8(P＜0.05). At week8, no significant differences of expression levels of these gens were detected between the two species, while at week16expression of the three genes in liver of Heiwu duck were much higher than Peking duck, especially the FAS (P＜0.05).4.Plasma TG and TC concentrations of both Peking duck and Heiwu duck were negatively correlated with body weight and liver weight (P<0.05). In Peking duck, plasma LDL and glucose contents were negatively correlated with body weight (P<0.05), while expression levels of ACC and FAS in liver were positively correlated with body weight, subcutaneous and abdominal adipose tissue weight (P＜0.05), and DGAT2expression levels were positively associated with body weight and abdominal adipose tissue weight (P＜0.05). There were also significant positive associations between lipid metabolism related gene expression levels and plasma glucose, LDL and HDL contents. Moreover, in Peking duck expression of PPARywas positively associated with abdominal fat deposition (P＜0.01), while in Heiwu duck expression levels of C/EBPαin abdominal and leg adipose tissues were positively correlated with carcass weight (P＜0.05).Above research results indicated that there were significant differences of lipid metabolism between the large meat duck and Heiwu duck during the growth stages. Compared with Heiwu duck, Peking duck showed stronger lipid embolism abilities for not only fat synthesis in liver but also fat deposition in extra-liver adipose tissues. In addition, certain correlations were detected between plasma parameters, lipid metabolism related gene expression and lipid metabolism in duck, which suggested that in future research about the relations of them is useful to investigate the molecular mechanisms of duck lipid metabolism. |
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