ABSTRACT Genes participating in the changes of yolk lipids by unsaturated oils remain elusive. In this study, ducks were randomly assigned to 3 groups, fed with basal-diet (C), basal-diet-plus-2%-flaxseed-oil (FL), or basal-diet-plus-2%-fish-oil (F), respectively. A digital-gene-expression-profiling analysis of livers were performed after four weeks. Compared to C, 36 and 25 differently-expressed-genes (DEG) were identified in FL and F, respectively. These genes participated in lipid metabolism pathways. In both F and FL, the sterol 12 α-hydroxylase 1 gene was down regulated, as well as the fatty acid synthase gene and stearoyl-CoA desaturase gene. In FL, the fatty acid desaturase 2 gene (FADS2) and elongation of the very long-chain fatty acids protein 2 gene (ELOVL2) were up regulated, and the CYP2U (cytochrome P450, family 2, subfamily U) was down regulated. However, the FADS2 and ELOVL2 were down regulated in F to possibly prevent the redundancy of body n-3 PUFAs. In conclusion, FL and F had different molecular pathways to reduce yolk cholesterol and increase n-3 PUFAs. However, CYP8B1 and FADS2 were the key genes in the regulation of both of them. α-linolenic acid in the FL might be transformed to longer n-3 PUFAs. In addition, this study adds sequence information to duck.
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