Effects And Regulatory Of Restricted Feeding On Lipid Metabolism In Liver And Extrahepatic Adipose Tissue Of Drakes

Restricting feeding of male poultry can not only reduce breeding costs and improve breeding efficiency,but also reduce the deposition of fat in the body of male poultry,playing an important role in improving production performance and other aspects.However,there is still a lack of research on the effects and regulatory mechanisms of restricted feeding on fat metabolism in drakes.Therefore,this experiment took 180 G-line drakes of Tianfu Nonghua duck as the research object to explore the differences in growth performance and slaughter performance under three feeding conditions of free feeding(FF),restricted feeding 20%(RF1)and restricted feeding 30%(RF2)during 5-8 weeks of age.Subsequently,using transcriptome sequencing technology to conduct comparative transcriptome analysis of liver,abdominal adipose and subcutaneous adipose of FF and RF2 groups drakes,and exploring candidate genes that regulate lipid metabolism in drakes under restricted feeding conditions,and screen key metabolic pathways involved in lipid metabolism in drakes under restricted feeding conditions.The main results are as follows:(1)The weight growth trends of the FF,RF1,and RF2 groups were basically consistent,but as the degree of feeding restriction increased,the growth rate of drakes slowed down(FF > RF1 > RF2).At the ages of 6,7,and 8 weeks,the body weight of the FF group was significantly higher than that of the RF1 and RF2 groups(P < 0.05).Subsequently,comparative analysis revealed significant differences in slaughter traits between the free feeding group and the restricted feeding group at 7 and 8 weeks of age.Meanwhile,the liver index and subcutaneous adipose rate of FF drakes were significantly higher than those of the RF2 group(P < 0.05),while the abdominal adipose rate was significantly higher than that of the RF2 group(P < 0.01).(2)The transcriptome sequencing results of liver,abdominal adipose and subcutaneous adipose of drakes in FF and RF2 groups showed that there were 279 differentially expressed genes(DEGs)(109 up-regulated and 170 down regulated)in the liver of RF2 group,390DEGs(93 up-regulated and 297 down regulated)in the abdominal fat of RF2 group,and 557DEGs(231 up-regulated and 326 down regulated)in the subcutaneous fat of RF2 group,compared with FF group.The results of the VENN plot showed that 7 DEGs were differentially expressed in the liver,abdominal adipose,and subcutaneous adiposeof both groups.Meanwhile,functional enrichment analysis of these DEGs revealed that the DEGs in the liver were mainly enriched in cellular aging and TGF-β Signal pathways,ECMreceptor interactions,glycerol phospholipid metabolism,and other pathways.DEGs in abdominal adipose were mainly enriched in the ECM receptor interaction,cell adhesion molecule,aggregation adhesion,metabolic pathways and other pathways.DEGs in subcutaneous adipose were mainly enriched in metabolic pathways,amino acid biosynthesis,regulation of actin cytoskeleton and other pathways.It is worth noting that ECM-receptor interaction and metabolic pathways were significantly enriched in liver,abdominal adipose and subcutaneous adipose,while DEGs in abdominal adipose and subcutaneous adipose were significantly enriched in lipid metabolism related pathways,including fatty acid metabolism,unsaturated fat acid synthesis and steroid biosynthesis.(3)Through integrated co expression network(WGCNA)and protein protein interaction(PPI)analysis,it was found that there were significant changes in lipid metabolism pathways in drakes under restricted feeding conditions.The ECM-receptor interaction and metabolic pathway pathways were significantly enriched in liver,abdominal adipose,and subcutaneous adipose.In addition,DEGs were significantly enriched in the glycerol phospholipid metabolism pathway of the liver,and fatty acid metabolism,unsaturated fat acid synthesis,and steroid production pathway of abdominal adipose and subcutaneous adipose.It is worth noting that WGCNA analysis screened three key modules(blue,black,and red),and functional enrichment analysis of the three modules showed that almost all genes aggregated in the blue module were related to metabolic pathways.Functional enrichment showed that lipid metabolism was the main factor,and most of the genes aggregated in the black and red modules were also related to metabolic pathways.At the same time,through statistical analysis of the nodes in the PPI network,10 core DEGs(HMGCS2,ALDOB,FTCD,PHGDH,ALDH8A1,ITGA2,PCK1,NME4,TAT,and PSAT1)involved in ECM-receptor interactions and lipid metabolism pathways were further identified.In conclusion,this study found that 30% restricted feeding of drakes at 5-8 weeks of age could significantly reduce their subcutaneous adipose and abdominal adipose deposition,which may be closely related to the ECM-receptor interaction and metabolic pathways(fatty acid metabolism,unsaturated fat acid synthesis and steroid biosynthesis).These results play a theoretical foundation for understanding the regulatory mechanism of lipid metabolism in drakes under restricted feeding conditions.