Association Of HSP70-1 Polymorphisms And Relationship With Thermal Tolerance In Chinese Hostein Cows

Heat stress can damage physiological health of dairy cows, and affect the production performance of dairy cows, bring serious loss of production. HSP70 as a molecular chaperone, can protect the body against or mitigate harm of heat stress. Using temperature humidity index as the reference standard, compare the difference of blood biochemical index, physiological and production of heat stress and non heat stress period. The experiment was using the method of PCR-SSCP to detect the HSP70-1 gene single nucleotide polymorphism, using the Western-blot method to detect the level of lymphocyte HSP70 protein expression. Analyze the relationship between expression of Hsp70 leval, rectal temperature with SNPs locus by SPSS software.Experiment I:The experiment was divided into two times, In 2013 November to 2014 January (non heat stress period) and 2014 July to September (heat stress period) period, selecting 458 Holstein cows as experimental animals. Temperature humidity index, production of dairy cows, physiological index and serum biochemical indexes were measured. The results show that the THI of non heat stress period<72, then the heat stress period,78<THI<89, cows in moderate heat stress. Showed that were in a moderate heat stress, cows physiological status change, rectal temperature increased significantly (P<0.05), Respiratory frequency increased extremely significant difference (P<0.01). Production performance, the milk yield, milk protein rate dropped significantly (P<0.05), decreased by 17.75% and 5% respectively, milk protein rate significantly decreased (P<0.01), decreased by 23%; Serum biochemical index, serum T4, Cor concentration significantly decreased (P<0.01), decreased by 23.80% and 36.20% respectively. Serum T3, INS concentration decreased, but the difference did not reach significant level (P> 0.05), serum Glu significantly decreased (P<0.01), decreased by 25.50%, there was no significant difference between serum TG concentration; The serum BUN concentration significantly increased (P<0.01), increased by 32.14%.Experiment II:Using the method of PCR-SSCP, detected the gene of HSP70-1 single nucleotide polymorphisms in cows. Based on CNKI registration number of AY149619 HSP70-1 gene, using primer 5.0 designed 12 pairs of primer, SNP detection of gene of HSP70-1 in 458 cows. Found C-A mutation happened in 1112 sites, there were three genotypes:AA, AB, and BB. T-C mutation in 3390 locus, there were three genotypes:CC, CD, DD. mutation T-C in 4583, there were two genotypes:EE, EF; A base is missing in 5886 locus, has two genotypes:HH, HI. The rectal temperature and HSP70 expression level with SNPs for correlation analysis. The HSP70 are measured with Western Blot, using SPSS software to establish a general linear model. The experimental result shows that C1112A sites with rectal thermometer and HSP70 have Significant correlation. AA and AB individual rectal temperature significantly below BB individuals (P<0.05), AB individual amount of HSP70 protein expression was significantly lower than AA, BB (P<0.05). Showed that AB individual cows has better heat resistance, can be used as a cows of molecular genetic markers. Other SNPs have no associated with rectal temperature and level of HSP70 expression.