Estimation Of Feed Efficiency Parameters And Association Research Of The Candidate HLCS

Feed efficiency is an economically important factor,feed cost is typically 70% of total cost of pig production.The improvement of feed efficiency at this stage is the indirect response of the continuous growth rate and backfat thickness selection of the pig.In developed pig breeding countries,feed efficiency have been put into the objectives and shared more weights.Compared with the developed countries there are still many basic work lags in the research and development of basic parameters of pig breeding in China,and the determination of feed utilization has long been used abroad,and it has not combined with the actual situation of our country.At the same time,the problem of lacking uniform measurement norms and standards for the huge number of testing data result that,accessed data can not be directly used for genetic assessment.Meanwhile,the major candidate gene of FE and its regulatory mechanism is still not clear.Therefore,a total number of 1290 US line Duroc pigs were used to analyze the determination stage of feed utilization efficiency,and the RFI correction formula was established and further analysis of the candidate genes.The main results are as follows:1.SAS software was used as the main software to calculate 90-180 d,105-180 d,120-180 d,135-180 d,150-180 d,and 165-180 d stages RFI and the correlation of each stage hrough four different calculation methods.The results showed that the regression equation is very significant(P <0.01),and the fitting degree is high,which is 0.9734,which indicates that 105-180 d and the whole period have the highest correlation between the different calculation formulas.2.Descriptive statistics,Heritability,genetic correlation,phenotypic correlation of the RFI?FCR?ADFI?ADG?100kg BF?90d BW?180d BW?Metamid BW?LEA and 30~100kg ADG in Duroc population was conducted by MTDFREML and SAS software.The result showed that feed utilization efficiency showed the medium heritability(0.18~0.46).Genetic and phenotypic correlations between RFI and FCR,RFI and ADFI were positively high.Genetic and phenotypic correlation of FCR with ADFI and ADG were high,either.3.Linear correction and SAS NLIN process were used to form the correction formula for Duroc pig 100 Kg RFI trait.The result indicate that the correction coefficient were 0.0519 and 0.0179 for boars and sows.Using the correction coefficient,the correction values of the early traits and the correction values of the whole traits were obtained respectively.The correlation analysis and the correlation analysis showed that the correlation coefficient was very significant(P <0.01).Note that the correction formula is appropriate.4.In our previous genome-wide association analysis(GWAS),five SNPs were found to be significantly associated with RFI traits.The most significant locus ASGA0059961 was located in the HLCS gene.In this study,we selected HLCS gene as a candidate gene for affecting RFI traits.Pool analysis,mass spectrometry analysis and correlation with feed efficiency.The results showed that a SNP locus rs 417014705 G> A was significantly associated with RFI,ADFI,FCR and TFI in the promoter region of the HLCS gene(P <0.01).The results of chi-square test showed that rs 417014705G> A had low genetic diversity,and its frequency and genotype frequency did not reach Hardy-Weinberg equilibrium in the experimental Duroc group.The above results indicate that the rs 417014705 G> A and the locus of porcine HLCS gene can be further studied as the genetic marker of pig feed efficiency in breeding work.