Abstract:

【Objective】 The effect of docosahexaenoic acid (DHA) on lipid metabolism in broiler were studied in order to provide test results for PUFA regulating fatty deposition. 【Method】 One-week-old AA Broiler were fed DHA microalgae, and slaughtered after two weeks. The tissues were reserved for isolating total RNA. RT-PCR was used to analyze the expression changes of genes. 【Result】 DHA microalgae significantly increased average body gain and feed conversion rates, reduced the levels of total cholesterol TC, TG and low-density lipoprotein cholesterol in serum, and increased the content of high-density lipoprotein cholesterol. One week later, the effects were still remained. In liver tissue, DHA microalgae increased the expression of PPARα and CPT-1. One week later, it was observed that DHA up-regulated the expression of FAS, ACC, LPL and CPT-1. Two weeks later, it still increased the expression of FAS and CPT-1, but a converse result was observed for ACC and LPL. In adipose tissue, DHA microalgae suppressed the expression of PPARα and LPL, up-regulated the expression of ACC, FAS and CPT-1. After stop adding, the expression of genes in test group were significantly lower than the control group (P＜0.01). In the muscle of chest, DHA microalgae significantly inhibited the gene expressions (P＜0.01). One week later, the expression of FAS, LPL, CPT-1 in test group were significantly higher than the control group (P＜0.05). Two weeks later, it was shown that DHA significantly inhibited fat synthesis and decomposition. In the leg, DHA microalgae significantly declined the expression of FAS, and increased the expression of ACC, LPL, and CPT-1. After one week, the inhibition was still significant. But two weeks later, the contrary result was observed. Chest and leg were not detected a large number of expression of PPARα, probably because of the less expression in muscle tissues or the regulation of PPARα had no relation to the case. 【Conclusion】 DHA microalgae can promote fat synthesis in the liver and inhibit in adipose and muscle tissues. It still has effects after one week of ceasing.

Key words: DHA, broiler, adipose tissue, liver, lipid metabolic genes