Analysis Of Chicken Meat Quality In Zhejiang Province And Study On Molecular Mechanism Of Leptin Receptor Gene In Lipid Metabolism

In this experiment, we investigated the body size, slaughter traits and the chemical composition including intramuscular fat (IMF), inosinic acid, fatty acid and amino acid of chicken breast muscle, in order to make better use of the excellent genetic resources. The correlation of body size and slaughter traits was analyzed. The relationship between intramuscular fat contents and mRNA expressions of leptin receptor (LEPR) and uncoupling protein (UCP) genes expression were analysed. The effects of LEPR gene on the expression of fat metabolism related genes and the regulation mechanism of LEPR on the fat metabolism were studied by using real-time PCR, and RNA interference (RNAi). Results are as bellow:1. Body size and slaughter traits measurementThe body size and slaughter traits of five different chicken breeds and four hybrid breeds were measured. The crossbreeding improved the body size and slaughter traits of chicken.2. Analysis of chemical compostion of chicken meatThe Wenchang X Habote chicken (WHC) has the highest intramusculat fat content, and Xianju chicken (XJC) has the lowest; the Xiaoshan×Xianju chicken (ZNY1,120d) has the highest inosinic acid contents and Xiaoshan chicken (XSC) has the lowest. The relative contents of unsaturated fatty acid in chicken breast muscle of Wenchang chicken (WCC) and Xiaoshan X Guangxi yellow X Xianju chicken (ZNY2) are the highest. XJC has the highest relative contents of poly-unsaturated fatty acid (PUFA) contents. ZNY2 has the highest contents of amino acid and essential amino acid (EAA). The age of chicken can influence the contents of intramuscular fat in breast muscle of Xiaoshan X Xianju chicken significantly (P<0.05), while has no significant influence on inosinic acid content, fatty acid (P>0.05). The total amino acid contents tend to decrease with the age.3. Relationship between intramuscular fat contents and mRNA expressions of LEPR and UCP genes.The IMF content has middle correlation with LEPR gene and low negative correlation with UCP gene in the four detected chicken breeds.4. The expression characteristic of LEPR and other fat metabolism related genes in chicken adipocytesThe expression levels of LEPR, UCP, peroxisome proliferation-activated receptor y (PPARy), fatty acid sythase (FAS), adipose triglyceride lipase (ATGL) and Adiponectin genes increased with the adipocyte differentiation and reach the peak at 6,4,10,6,6,10 day respectively. And the abundance of IGF-I gene increased gradually with the differentiation of chicken adipocytes.5. Effects of LEPR gene knockdown on expression of UCP, PPARy, FAS, ATGL, Adiponectin and IGF-I genes in chicken adipocytesThe expressions of UCP, PPARy, FAS, LPL, ATGL genes decreased significantly after the silenceing of LEPR gene (P<0.05), while the expressions of IGF-I and Adiponectin increased significantly (P<0.05)6. Effects of oleic acid on expression of LEPR and other fat metabolism related genes in chicken adipocytesOleic acid can induce the expression of LEPR, UCP, PPARy, LPL, Adiponectin and suppress the expression of ATGL and IGF-I genes in chicken adipocytes. LEPR gene knockdown can weaken oleic acid's effects on inducement of adipocyte differentiation related genes'expression. The results suggest that LEPR gene may play an important role in regulation of adipocytes differentiation induced by oleic acid.