Construction Of Different Gene Expression Profile Between Bull And Steer In Red Steppes By Genechip

Meat quality and carcass traits are comprehensive, including a series of evaluation index. There are so many factors affecting the meat quality and carcass traits and we know little on meat quality, flavor, and taste. For thoroughly understanding the factors on genetic mechanisms of meat quality, it requires rapid and efficient methods to find major specific expression genes in bovine muscle to provide the molecular basis for scientific breeding.The phenotype data of carcass and meat quality traits of 60 cattle (30 bulls and 30 steers) were collected after breeding and they were slaughtered at same conditions. Meat quality and carcass traits were compared between bulls and steers. Bovine longissimus dorsi muscle (LD) samples from 3 bulls and 3 steers were collected to research the different gene expression profile of LD to find differential expression genes in our experiment by gene chip. The results were verified by fluorescence quantitative PCR (FQ-PCR).The results were as follows:In carcass traits, body weight before slaughter, net yield of meat,daily weight gains,carcass weight, meat percentage of carcass, dressing percentage, meat percentage in bulls were significantly higher than that of steers (p<0.05). In the top grade beef, sirloin, the fillet, big topside, and little silverside in bulls were significantly higher than that of steers (p<0.05). In meat quality traits, the dehydration rate in bulls were significantly higher than that of steers (P<0.01). The shear force and muscle fibre diameter in bulls were significantly higher than that of steers (p<0.05).In analysis of nutritional component of meat, dry matter and crude protein in bulls were signifieantly lower than that of steers and the original moisture was significantly higher than that of steers (P<0.05) . In the composing of amino the acid, glutamic acid, serine, histidine, valine, methionine, Phenylalanine, lysine, palmitoleic acid, oleic acid , linoleic acid , linolenic acid and total of amino acid are lower than that of steers (P<0.05). Content of the tetradecylic acid in steers was higher and content of hexadecanoic acid and stearic acid were lower than that of bulls (P<0.05) .Red Steppes bulls(n=3) and steers (n=3) were selected randomly to analyze the LD differentially expressed genes on growth and development and fat metabolism by Affymetrix gene chip, numbers of 22810 probes were detected, numbers of 16321 have hybridization signal, it holds 71.6%. 403 genes that have relative high amino acid similarity with known functional gene, it holds 76.18%, while 126 genes whose functions are still unknown after comparison analysis, which were 23.82%.The results of 529 differential expression gene by GO analysised were showed 294 gene can find notations on biological process, 121 gene can find notations on cellular component, 243 gene can find notations on molecullar function, 126 gene was not found notations. Each functional group can be independently divided into different sub-groups which are also divided downward, all these groups comprise branch architecture of Ontologics and each has different biological function. Total 25 genes which relating with growth and fat metabolism were founded from the results of GO classify by gene comment.ADH5, OXSM, FABP3, ARPC3, BDKRB2 had founded in the pathway of Fatty Acid Metabolism, Bile Acid Biosynthesis, Fatty Acid Biosynthesis, PPAR Signaling Pathway, Regulation of actin cytoskeleton. They are correlated with fatty acid metabolism, muscle development and growth regulation.Five representative genes were selected to verify the result of gene chip by FQ-PCR. The results of FQ-PCR are consistent with gene chip. Gene expression changes were consistent with the physiological characteristics, the difference genes were accurated.IGF1, IGF2, IGF1R, IGFBP3, IGFBP5 mRNA expression variance of 8 tissues (heart, liver, spleen, lung, kidney, rumen, duodenum, longissimus dorsi) were analyzed, the results were different, which may be related with male hormone secretion reduced after castrated caused liver IGFs expression changed.In this research, gene chip was employed to construct the bovine longissimus dorsi muscle tissue gene expression profile and analyze the different gene expression between bulls and steers. We use the FQ-PCR to verify parts of the genes' expression. The results will build solid base for the study of major genes with meat quality and carcass traits.