The Regulation Mechanism Of Muscle Fiber Development And Intramuscular Fat Deposition In Three Goose Breeds

Muscle fiber development and intramuscular fat deposition are important components of muscle tissue development,and are also the key to affecting meat flavor.The sizes of muscle fiber diameter/area directly determine muscle tenderness,and the content of intramuscular fat is positively correlated with meat flavor and juiciness.In recent years,some studies have reported that there seems to be a certain relationship between muscle fiber development and intramuscular fat deposition.During the muscle growth of poultry,the stage of simultaneous muscle fiber development and fat deposition in the muscle began after 6 ～ 8 weeks of age.In order to further reveal the mechanism of the relationship between muscle fiber development and fat deposition,this experiment used 10 and 30 weeks old Gang geese(GE),Landes geese(LD)and Sichuan white geese(SW)as experimental materials to explore the phenotypic differences and molecular regulation mechanism of muscle fiber development and intramuscular fat deposition.The main results are as follows:(1)Comparing 30 weeks of age with 10 weeks of age,the breast muscle weight/rate of all three breeds of geese was highly significant higher than that of 10 weeks of age(P <0.01);in addition,the muscle fiber diameter and area of all three breeds of geese were highly significant higher than that of 10 weeks of age(P < 0.01),while the muscle fiber density was highly significant lower than that of 10 weeks of age(P < 0.01);oil red O area ratio and muscle fiber area ratio except for LD,which did not reach a significant level,SW and GE all reached significant differences(P < 0.05).(2)Transcriptome sequencing results showed that there were 150,130,and 120 differentially expressed genes(DEGs)related to muscle fiber development in GE,LD,and SW at 30 weeks of age compared with 10 weeks of age,respectively,which were significantly enriched to 3,4,and 3 KEGG pathways related to muscle fiber development,respectively.Among them,Regulation of actin cytoskeleton and Focal adhesion were enriched in all three breeds.Rap1 signaling pathway and Ras signaling pathway were also enriched in LD.There were 72,36,and 55 DEGs related to fat deposition in GE,LD,and SW,respectively.The DEGs of these three breeds were significantly enriched to 5,3,and4 KEGG pathways related to intramuscular fat deposition,respectively.Among them,cholesterol metabolism and PPAR signaling pathway were enriched in all three breeds.AMPK signaling pathway was also enriched in GE.Fatty acid metabolism pathway was also enriched in SW.(3)Protein-protein interaction(PPI)analysis of DEGs showed that muscle fiber development could be directly regulated by CAV1 belonging to the focal adhesion pathway in GE,and intramuscular fat deposition could be directly regulated by PPARD belonging to PPAR signaling pathway in SW.Other goose breeds can only indirectly regulate muscle fiber development through key genes.