Investigation On The Correlation Between Animal Development And Meat Traits Related Genes Expression Or Microbial Diversity Of Gastrointestinal Flora

As a province excellent local livestock and poultry breeds, Wenshang Luhua chickens and Luxi cattle have a great potential in their meat, so taking good advantage of their excellent properties, develop their fine features, and cultivate local varieties with unique genetic characteristics and advantages are Chinese important strategies responsing to foreign challenges in livestock and poultry. However, simply by the means of conventional genetic improvement and nutritional regulation to improve the meat of livestock and poultry has been facing bottleneck, therefore, taking the use of traditional methods, combined with molecular biology methods to study the growth and development stages of animals will have important practical significance to the improvement, large-scale farming and production of livestock and poultry.In this study, we used modern molecular biology techniques, analyzed the sequence polymorphisms of meat quality traits’candidate genes to explore the dominant genes, and laid the technical foundation for new genetic resources innovative; meanwhile, we created an excellent original research material of meat quality, and greatly reduced the breeding process, which had very considerable economic and social benefits. We selected negative regulatory factor-myostatin (MSTN) gene associated with muscle traits and transmembrane protein18(TMEM18) gene associated with fat metabolism as candidate genes to research the meat quality traits of Wenshang Luhua chickens and the fattening period of Luxi cattle, and analyzed SNPs in both genes and their genetic diversity in Wenshang Luhua chickens and Luxi cattle. By analyzing the correlation between SNPs and the quality traits, evaluating its genetic effects; constructing eukaryotic expression vectors, transfecting, performing semi-quantitative RT-PCR and Real-time PCR etc. to verify its function and clarify its genetic mechanisms, looking for quality traits associated molecular markers, then establish a high-quality marker-assisted selection of livestock and poutry.The results showed that the upstream sequence of WLc-MSTN gene has13E-boxes, among which the E3-box and E4-box have nuclease polymorphism. In vivo and in vitro expression studies of MSTN gene showed that E-box plays an important role in the regulation of MSTN gene transcription process, MSTN gene expression levels can be changed by E-box polymorphisms, different E-boxes have different transcriptional regulatory capacities in MSTN gene. We discovered a SNP in861bp upstream of transcription start site of Lc-MSTN gene, in vitro expression experiments showed that the upstream sequence containing the polymorphism sites has a certain activation to the promoter, so we think that the SNP can enhance promoter activity and plays an important role in regulating MSTN gene transcription process. The Luxi cattle’s541bp upstream of TMEM18gene transcription start site is SNP, in vitro expression experimental results showed that the polymorphism sites has little effect in enhancing the promoter.Livestock and poultry’s digestive tract is a complex and diverse environment, where there is a wide variety and a huge number of microbes, these microbes plays an important role in host’s various physiological and biochemical reactions, digestion of food and absorption of nutrients, immune regulation and so on. There is a developmental symbiotic relationship between animal’s gastrointestinal and micro-organism communities, alteration of intestinal flora can cause the weakness of body’s gastrointestinal tract barrier function, decreasing absorption of nutrients, reduction of the body’s immune system, then finally affecting the animal’s growth and development.We used the technique based on the16S rDNA PCR-DGGE to study Luxi cattle’s intestinal microbial community structure and composition fed different levels of rapeseed, as well as the growth and development of Luxi cattle. The results showed that different parts of the gastrointestinal has its special microbial community. The highest microbial diversity within the rectum, the microbes in rumen and small intestine is fewer relatively, among which the rumen microorganisms is fewer in species and numbers, mainly methaneogens. A lot of Pseudomonas was found in large intestine components fed with high levels rapeseed, and these individuals exhibited diarrhea, therefore, it was confirmed that high levels of rapeseed can adversely affect the body’s digestion. These results provided a scientific basis for the rational using of rapeseed as feed additives, improving of the nutritional condition, regulation of gastrointestinal flora balance, improving disease resistance and performance of Luxi cattle, and openning up a more effective way to the study of beef cattle probiotics.