| Protection and utilization of local pig breeds can enrich the information of Chinese pig genetic resources.As one of local excellent pig breeds in our country,Qing ping pig has excellent characteristics of delicious meat and short gestation.In order to establish a complete theoretical basis for the preservation and utilization of Qing ping pigs,the germplasm characteristics such as appearance,growth and development,fattening performance,carcass quality and reproductive performance of Qing ping pigs were measured.The relationship between the polymorphic loci of GALP and RBP4genes and reproductive traits was detected at the molecular level.The unique genetic variation information of Qing ping pigs was excavated by whole genome resequencing technology.The main research results are as follows:I.Main Germplasm characteristics of Qing ping pigs1.Body appearance:Qing Ping pig hair color,all black skin,coarse and long hair on the temples,stiff,medium head,ear big droop,mouth tube long straight,back and waist flat,occasionally depressed,hip plump.The number of effective nipples of Qing ping sows was 15.65.The effective number of nipples of Qing ping boars were 14.71.2.Body size appearance:24 months old boar weight 132.52 kg,body length:152.36 cm,body height 73.04 cm,chest circumference 127.21 cm;The weight of the sows was 121.16 kg,the body length was 136.25 cm,the body height was 62.86 cm and the chest circumference was 125.86 cm.Except chest circumference,other indexes of Qing ping boars were significantly higher than that of Qing ping sows.Compared with other local pig breeds,Qing ping pig is in medium size.3.Growth and fattening:Birth weight of Qing ping sows was 0.75 kg,weaning weight was 7.13 and weight of 120-day-old sows was 44.33 kg.Qing ping boars were0.81 kg at birth,8.36 kg at weaning and 50.71 kg at 120 days of age.The boar’s daily gain of boars during fattening period was 402.5 g,and the feed conversation ratio was3.14:1.The sow’s daily gain of sows during fattening was 379.24 g,and the feed conversation ratio was 3.30:1.4.Reproductive performance:The average total number of born was 10.95,the number of born alive was 10.52,the gestation period was 112.76 days,the litter weight at birth was 10.02 kg,the number of live piglets at weaning was 10.02,and the litter weight at weaning was 71.51 kg.The survival rate of weaning was 95.66%.The average sperm extraction was 158.32ml,sperm motility was 0.90,and sperm density was 1.17.The above data indicated that Qing ping pigs had early sexual maturity,short gestation period,large litter size and strong reproductive performance.5.Slaughter performance:The live weight before slaughter of Qing ping was 72.80kg,the carcass weight was 51.40kg,the slaughter rate was 70.33%,the average backfat thickness was 34.61mm,the logarithm of ribs was 14.30 pairs,and the ratio of leg to hip was 28.37%.Fat percentage was 35.82%,skin percentage was 11.25%,skin thickness was 3.94mm,lean meat percentage was 43.10%,bone percentage was 9.83%,eye muscle area was 18.41 cm~2,carcass length was 84.04cm.The slaughter percentage,lean meat percentage and eye muscle area of Qing ping pigs were all higher,which indicated that Qing ping pigs had better meat production performance.6.Meat quality:Qing ping pork color score 1 was 3.78 points,meat color score 24was 3.25 points,marbling score was 3.76 points,p H1 value was 6.55 points.p H24value was 5.74,drip loss was 2.69%for 48h,water power was 92.09%,intramuscular fat was 3.96%,moisture was 72.40%,tenderness was 60.69 N.The above results show that Qing ping pork is bright red in color,rich in intramuscular fat,rich in myoglobin,strong in water power,no PSE,DFD meat,and high in meat quality.7.The content of flavor nutrients in Qing ping pork:The total amino acid content per 100g meat sample was 21.88g.The contents of aspartic acid and threonine in Qing ping pigs(1.88g and 1.66g)were significantly higher than those in DLY pigs(P<0.05).The EUC value of the synergistic umami effect of inosine and glutamate in Qing ping sows was 405.71,which was significantly higher than that of DLY sows.The myrisic acid content of Qing ping pigs was significantly higher than that of DLY pigs(P<0.05).The total content of iron,zinc and other elements in Qing ping pigs is higher than that in DLY pigs.Qing ping pork has better taste and richer nutrition.Ⅱ.Excavation of genetic variation in Qing ping Pigs1.The frequency of GALP and RBP4 genotypes and alleles in Qing ping pig population were detected,and their association with reproductive traits was analyzed.Only CC genotype was found in Qing ping pig population.In RBP4 gene,The gestation period of AA and AB genotype was shorter than that of BB genotype,and the difference between AB and BB genotype was significant.The total litter size of AA and AB genotype was significantly higher than that of BB genotype.The RBP4 mutation site was significantly correlated with the reproductive performance of Qing ping pigs and could be used as an auxiliary marker for breeding sows with high fecundity.2.Mining of SNP,indel and other genetic variation information of Qing ping Pigs:A total of 74 Qing ping pigs were selected as a population and 30 pigs of seven other breeds,including Duroc,LA and EHL,were selected as a population.A total of 746,266SNPs and 122,752 specific indel were obtained from Qing ping pigs.SNP and indel genes among which the most enriched were in the biosynthesis of secondary metabolites,MAPK,PI3K-Akt and other signaling pathways,which were closely related to childbirth.These specific genetic variations indicate that Qing ping pigs have rich specific genetic information and are closely related to the characteristics of short gestation period.3.Genetic structure analysis of Qing ping Pig population:Qing ping pig was significantly separated from the other seven breeds at the earliest and clustered closely together.When the optimal K value was 5,three ancestry components appeared,indicating that the genetic source of Qing ping pig was relatively complex,but it had a highly unified breed lineage and stable specific genetic information. |
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