Screening Of Differentially Expressed Genes In The Ovarian Transcriptome Of Wanyue Black Pigs And Yorkshires During Puberty

Pig is one of the most important meat resources in China and occupies an important position in Chinese agricultural production.The ovary is a very important reproductive organ of sows,which plays its role by secreting reproductive hormones and regulating follicle development.The first estrus of sows is a sign of sexual maturity,and the early or delayed puberty seriously affects the reproductive performance of sows,and the initiation of puberty is regulated by both genetics and hormones of sows.In this study,Wanyue Black pigs and Yorkshire at puberty were selected as the research objects,and the key candidate genes were screened by sequencing analysis of reproductive hormone levels,ovarian tissue morphology and ovarian transcriptome of the two kinds of pigs.In order to explore the relationship between the key genes in the ovary and the secretion of reproductive hormones in the serum of gilts during puberty,further explore the initiation mechanism of puberty and the differences in reproductive performance between Chinese and foreign gilts,and provide a reference for the study of the differences between local pigs and foreign pigs.The main research contents and results are as follows:1.E2(estrogen)of Wanyue black pigs was significantly higher than that of Yorkshire(P<0.01);The concentrations of Gn RH(gonadotropin-releasing hormone)and P4(progesterone)secreted by Yorkshire were significantly higher than those of Wanyue black pigs(P<0.01).PRL(prolactin),LH(luteinizing hormone)and FSH(follicle-stimulating hormone)were not significantly different(P>0.05).2.There was no significant difference in the number of follicles on the left and right sides of ovaries between Wanyue black pigs and Yorkshire at puberty(P>0.05).The thickness of left ovarian tissue and the length,thickness and weight of right ovarian tissue of Yorkshire were significantly higher than those of Wanyue black pigs(P<0.05).There were no significant differences in follicular morphology between Wanyue black pigs and Yorkshire at different periods(P>0.05).3.A total of 188 differentially expressed genes were identified in the ovarian tissues of Wanyue black pigs and Yorkshire at puberty,including 100 up-regulated genes and 88down-regulated genes.4.Through GO enrichment and KEGG pathway analysis,the GO function of differentially expressed genes is mainly responsible for the regulation of reproductive process,cell proliferation regulation,sexual reproduction and oogenesis,which are mainly involved in catalysis,molecular transducer and transporter activity.KEGG pathway enrichment analysis showed that differentially expressed genes were mainly involved in estrogen signaling pathway,steroid biosynthesis and ovarian steroid production,and these pathways were involved in the regulation of follicle growth and development and reproductive hormone synthesis.Through bioinformatics analysis,14 key candidate genes were initially screened: RLN2,ZP2,TIMP1,CLU,KITLG,UGT1A6,AKR1D1,HSD3B1,LOC100515166,SHC2,FOS,MMP9,BMP15,CYP19A1,These genes may play an important role in the synthesis of steroid hormones,the secretion of reproductive hormones,the development of ovarian follicles and the regulation of ovarian function in Wanyue black pigs and Yorkshire during puberty.These genes were verified by RT-q PCR,and the results were in good agreement with the sequencing results.