| Currently, as improvement of dairy cows farm management and effect of gene selection, milk yield of dairy cows in intensive farms increases rapidly, reproduction efficiency decreases ceaselessly. The problem of low reproductive efficiency has been threatening the economic benefits of high productive dairy cows around the world. Inactive ovaries is a common follicular growth disorder in dairy cows postpartum, the function of ovarie is disturbed temporality, and the follicular have no cycle activity. Nutrition, metabolism, endocrine are the impact factors of follicular growth of postpartum cows. There are lots of reserch about that, but it is still unclear the relationship between postpartum inactive ovaries and the whole body metabolism in dairy cows. Therefore, in this experiment the theory and technology of metabolomics, namely gas chromatography/mass spectrometry technology(GC/MS), combined with multivariate statistical analysis and bioinformatics analysis were applied, characteristic metabolites in plasma from postpartum inactive ovaries cows were abtained and the relationship between characteristic metabolites and inactive ovaries of postpartum cows were clarified. It will provide the scientific basis for further revealing metabolic mechanism of postpartum inactive ovaries of dairy cows in the future.206 cows, which had similar age and parity in intensive dairy farm in Heilongjiang Province, were selected as the test animals. The postpartum cows were tracked to observe the estrus behavior and the size of follicular was checked by rectal examination and B ultrasound examination to determine estrus cows and inactive ovaries cows. 22 estrus cows were selected as control group(A) and 20 inactive ovaries cows as experimental group(B). The pathology change of two group were compared firstly. All plasma samples from two groups of cows were detected by GC/MS spectroscopy to contrast plasma metabolomic profiles between groups, combined with multivariate pattern recognition, the differential metabolites in plasma of inactive ovaries cows were screened and identified through pathway analysis, the relationship between inactive ovaries of dairy cows and involved pathway were determined.Results : 1) The analysis of clinical data, blood biochemical index, and reproduction hormone verified that the hormone change of estrus and inactive ovaries cows accord with their pattern, inactive ovaries cows have lower body condition score and Mg, E2 levels, higher NEFA level. 2) There are 20 differential metabolites in plasma of postpartum cows with inactive ovaries and estrus cows, among that 17 differential metabolites, including an increase of cholic acid, and the decrease of vanillylmandelic acid, nicotinoylglycine, 6-hydroxynicotinic acid, beta-alanine, L-tyrosine, phenylpyruvate, These metabolites were closely related to abnormality of phenylalanine, tyrosine and tryptophan biosynthesis, propanoate metabolism, nicotinate and nicotinamide metabolism, phenylalanine metabolism, tyrosine metabolism, glucose and purine metabolism. The abnormal of amino acid metabolic pathway make the insufficiency of amino acid which essential to follicles growth, further the growth of follicles will be suppressed. The decrease of nicotinic acid will influence the lipid metabolism, the high concentration of free fatty acids makes cytotoxicity increase, the growth of follicles was blocked. Glucose metabolism and purine metabolic pathways may also be affected, further the energy supply of follicles growth will be affected. The high concentration of cholic acid in inactive ovaries cows revealed the close relationship between cholic acid and inactive ovaries in dairy cows. Moreover, the biological effect of another 3 differential metabolite such as iminodiacetic acid, N-Methyl-L-glutamic acid, 3-Aminoisobutyric acid on inactive ovaries in dairy cows need to be further confirmed.Conclusion obtained that GC/MS techniques combined with multivariate statistical analysis can effectively discovery differential metabolites in plasma of postpartum inactive ovaries in dairy cows, and reveal a metabolism changes of kinds of metabolites of postpartum inactive ovaries cows. It will lay a theoretical and methodological foundation for further studying postpartum inactive ovaries in dairy cows. |
