| With the development and integration of genomics,transcriptome,proteomics,metabolomics,bioinformatics and computing technology,the genetic decoding of important economic traits has been promoted greatly in pigs.Many major genes and molecular markers related to economic traits have been developed.Gene integrated breeding technology based on gene assisted selection has become an important means of pig improvement.In the cultivation of a new variety,gene integrated breeding technology can increase the accuracy of selection and accelerate the progress of genetic improvement,especially for the disease resistance and the meat quality(difficult to be measured without slaughter).With the improvement of people’s living standard,the demand for high quality pork is increasing.Cultivation of pig varieties with high meat quality is one of the main measures to meet market changes.From 1998 to 2017,a total of 15 pig breeds were approved by National Livestock Variety Approval Committee.These pig breeds have small body size or poor meat quality,and are generally used as dam.Cultivating a sire breed with large body size and high meat quality can improve the pig production system in China,and meet the change of market demand more flexibly.In this study,gene integrated breeding technology was applied to the cultivation of Shanxia black pig with large body size,fast growing,high feed efficiency and good meat quality.The combining ability between Duroc,Berkshire,Licha black pig,Yushan black pig,Wei pig and Luchuan pig was tested.The results showed that the overall combining ability of Berkshire and Licha black pig was best.Therefore,Berkshire and Licha black pig were used as founders to breed a new variety using cross breeding,namely,Shanxia black pig strain 1(Shanxiatu).VRTN,PHKG1,MUC13,FUT1,MYH4 and HMGA1 genes were selected for gene integrated breeding according to the breeding aim of large body size,fast growing,high feed efficiency and good meat quality.The polymorphsm of the 6 genes were tested in the two founders.MYH4 and HMGA1 genes were non-polymorphic,so they couldn’t be used for gene assisted selection in Shanxia black pig.The frequency of the favorate allele of FUT1 was low,and it was not suitable for gene assisted selection.The other 3 genes were highly polymorphic,and their favorate allele’s frequencies were high,so they were suitable for gene assisted selection.To verify the effects of VRTN on the number of thoracic vertebrate and PHKG1 on pH at 24 h,14 carcass traits and 14 meat quality traits were tested by slaughtered 358 individuals from the intercross between Berkshire and Licha black pig(BL).VRTN gene significantly affected the number(P < 0.0001)and length of thoracic vertebrate(P < 0.01),and had no effect on other recorded traits.The numbers of thoracic vertebrate of QQ and Qq were 1.2 and 0.5 more than qq,respectively.PHKG1 significantly affected muscle tenderness and backfat thickness(P < 0.05),and did not affect other meat and carcass traits.The backfat thickness of AC was thiner than CC,but shear force was higher than CC.PHKG1 gene had on significant effect on pH at 24h(P = 0.9056),but pH at 24 h of AC and CC were higher than AA.In the Shanxia black pig breeding populations,that is,Berkshire,Licha black pig,Lulai black pig(Shanxia black pig strain 2)and 0 generation and 1 generation of BL,a total of 2873 pigs was genotyped for VRTN,PHKG1 and MUC13 genes,and the artificial selection was assisted according to the genotypes of those genes.Their favorable allele frequencies in the second generation were higher than in first generation of BL,which indicated that gene assisted breeding took effect in the breeding program of Shanxia black pig.The frequencies of favorable allele of VRTN and MUC13 are less than 0.7,so there is still much room for improvement. |
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