This experiment was aimed to study the growth development and fit the growth curve of Pietrain pig.The body weight records were collected by Osborne FIRE system to study its regularity growth development (122 boars and 129 sows).The rapid growth period was centralized between 110 and 150 d, and the growth of Pietrain pig was fitted the typical S-curve.The relative growth intensity was higher for younger pigs, then decreased gradually.Three non-linear models including Logistic,Bertalanffy and Gompertz were utilized to fit the growth curve of Pietrain pig, though all the three models had good fitness,and R2 of the models (Logistic,Bertalanffy,Gompertz) for sow were 0.9815, 0.9589 and 0.9698, respectively.The results showed Logistic model played better for achieving the real observations.According to the fitting growth curve, the age of inflection value of boar and sow were 114.72 and 114.89 d,the weight of inflection value were 65.30 and 63.00 kg, the highest daily gain were 1.051 and 0.983 kg/d,respectively.

Tail analysis and genome-wide association studies(GWAS) were combined in this study to determine preliminary two tails selection criterions.A total of 2 000,1 500,1 000 and 500 samples and 20％,15％,12％,10％,8％,5％ of two tails were used to run GWAS to estimate the effects of the population size on GWAS and the effect of the proportion of two tails on GWAS,respectively.The results showed that the number of significant SNPs decreased with the reducing population size and the proportion of two tails.The preliminary selection criterions were:traits with heritability of about 0.38,the proportion of two tails of 8％,10％,10％ and 20％ from 2 000,1 500,1 000 and 500 samples,which were appropriate for two tails population for running GWAS,respectively.Further,the traits with heritability of about 0.50,the proportion of two tails of 5 ％,5％,10％ and 15％ from 2 000,1 500,1 000 and 500 samples were appropriate for two tails population for running GWAS,respectively.The present preliminary two tails selection criterions from populations with various sizes to run GWAS could detect significant SNPs effectively and also provide a strategy of reducing the cost of GWAS.

In this study,we cloned MAP 3K 5 gene cDNA sequence,compared the sequence of MAP3K5 with MAP3K families in pig and other species,and studied their conservative structure domain.Obtained the full-length of MAP 3K 5 gene (5 452 bp)by RACE-PCR,predicted the open reading frame (ORF)and amino acid (AA)sequence,and obtained the information of 31 exons. The low similarity were found in mRNA and amino acid sequences of MAP3K families in pig (<50%).And MAP3K5 had the comparatively high similarity with MAP3K6 in pig.The compar-ative analyzed the mRNA and protein sequence of pig MAP 3K 5 gene with other species MAP 3K 5 gene,founded that the ten species of MAP3K5 mRNA and protein sequence had the high similari-ty (>78%),and pig MAP3K5 had the comparatively high similarity with Bos taurus ,Ovis aries , Canis lupus and Homo sapiens .Function domain analyzed the high similarity protein with&nbsp;MAP3K5 in pig,this research found that pig MAP3K6 protein had the similar conserved function domain with pig MAP3K5.However,the other pig MAP3K families didn’t have the similar con-served function domain with pig MAP3K5.The ten species of MAP3K5 protein had the similar conserved function domain.The results obtained the sequence and molecular structure of MAP 3K 5 gene,and provided an important foundation for further function research of MAP 3K 5 gene in pig.

The objective of this study was to analyze two SNPs of HMGA1 gene,and investigate its association with feed efficiency related traits in Duroc populations.HMGA1 gene SNPs (g.-543 T>C and g.1356 C>T)in Large White pig and Min pig were detected by re-sequen-cing technology,SNP genotyping of g.-543 T>C and g.1356 C>T sites in Duroc populations were performed using Sequenom mass spectrometry,and the association of HMGA1 gene SNPs with growth and feed efficiency related traits in Duroc populations were analyzed.The results in- <br> dicated that the individuals of CT genotype in g.- 543 T > C increased 2.15 kg on 90 d body weight (P <0.05 ),decreased 3.21 d at 30 kg weight age (P <0.05 ),weaning weight was in-creased and 100 kg age were decreased,residual feed intake,30 to 100 kg average daily gain (ADG),40 to 90 kg average daily feed intake (ADFI)and 40 to 90 kg ADG were decreased,com-paring with CC individuals.Moreover the individuals of CC genotype in g.1356 C>T had signifi-cantly increased 90 d body weight (0.37 kg,P <0.05),ADFI (less 0.13 kg,P <0.05),back fat (BF,less 0.43 mm,P <0.05),RFI (less 70.40 g,P <0.05),30 kg age (less 0.56 d,P <0.05) and 40 to 90 kg ADFI (less 0.17 kg,P <0.05)were significantly decreased;Weaning weight and 100 kg age were increased;30 to 100 kg ADG,40 to 90 kg ADG were decreased than TT genotype individuals.And the CT genotype individual in g.1356 C>T had the similar results with CC gen-otype individuals that compared with TT genotype individuals.All in all,the two SNPs of HM-GA1 gene would be helpful in feed efficiency related traits in Duroc population.