Study On Growth & Reproduction Traits And Polymorphisms Correlation Analysis Of ESR & PRLR Genes Of Laboratory Tibet Mini-Pigs

OBJECTIVE: In this study, growth and reproductive performance of Tibet mini-pigs, whichwere raised under climatization and laboratory animalization conditions, were observed. Weinvestigated ESR and PRLR genes related with growth and reproductive performance. Theobjectives were to: (1) get information of Tibet mini-pigs raised in climatization and laboratoryanimalization conditions and search for the breeding and management way of Tibet mini-pigs toprovide us with the essential data for the experimental animalization of Tibet Miniature Pigs, (2)attain the information on polymorphism and their distribution of two genes in Tibet mini-pigs, and(3) determine the genetic effect of ESR and PRLR genes in Tibet mini-pigs, which can be used asMarker for selection of growth and reproductive trait.METHODS: TBN, NBA, numbers of piglets weaned, birth weight, 60-day body weight wererecorded. The fragments of ESR and PRLR genes of 44 Tibet mini-pigs were amplified by PCR,and then PCR products were cut by enzyme for analyzing the relationship between polymorphismand growth & reproduction performance.RESULTS: TBN, NBA, numbers of piglets weaned of first parity of laboratory animalizationTibet mini-pig swinery were higher than that of first parity of origin generation and climatizationTibet mini-pig swinery (t≥tmin=3.364, P≤Pmax=0.002). Numbers of piglets weaned of first parity of laboratory animalization Tibet mini-pig swinery were higher than that of latter parity oforigin generation (t=2.555, P=0.014). Birth weight, 60-day body weight of first parity oflaboratory animalization Tibet mini-pig swinery were higher than that of first parity and latterparity of origin generation and first parity of climatization Tibet mini-pig swinery (t≥train=3.798, P≤P max=0.001).Polymorphism of ESR and PRLR genes was analyzed. The genotypes were AA, AB and BB,respectively. PCR products (120bp) of ESR gene were cut by PvuⅡ. Gene with two fragments(55bp and 65bp) named BB genotype, 120bp fragmen only named AA genotype and threefragments (120bp, 65bp and 55bp) named AB genotype. 163bp PCR products of PRLR gene wascut by AluⅠ. Gene with two fragments (104bp and 59 bp) named BB genotype, three fragments(85bp,59 bp and 19 bp) named AA genotype, and four fragments (104bp,85 bp,59 bp and 19bp)named AB genotype.The genotypes of AA, AB and BB were 12, 22 and 10 sows, respectively. Genotypicfrequency of AA, AB and BB was 0.273, 0.500 and 0.227, respectively. Allele frequencies of Aand B were 0.523 and 0.477 in ESR gene, whereas in PRLR gene, the genotypes of AA, AB andBB was 10,23 and 11 sows, respectively. Genotypic frequency of AA, AB and BB were 0.227,0.523 and 0.250, respectively. Allele frequencies of A and B were 0.489 and 0.511, respectively.Growth and reproductive performance between different genotypes were different. In ESRgene, TBN of first parity was significant difference (F=3.579,P=0.037) between differentgenotypes. The TBN of different genetypes (AA,BB and AB) of the first parity were 3.500±1.446pigs, 4.900±0.994 pigs and 4.636±1.465 pigs. The tendency of TBN between differentgenotypes were BB＞AB＞AA and the differences between different genotype were 0.264 pigs and1.400 pigs. But other indexs had no significant difference (F≤Fmax=2.109, P≥Pmin=0.134). InPRLR gene, birth weight of latter parity had significant difference (F=4.301,P=0.021) betweendifferent genotypes. The birth weight of different genotypes (AA,BB and AB) of the latter paritywere 0.637±0.094kg, 0.616±0.050kg and 0.707±0.098kg. The tendency of birth weightbetween different genotypes were AB＞AA＞BB and the differences between different genotype were 0.070kg and 0.091kg. But other indexs had no significant differences (F≤Fmax=1.812, P≥Pmin=0.177).CONCLUTIONS: The breeding management under laboratory animalization conditions ofTibet mini-pigs is successful. It is helpful for laboratory animalization of Tibet mini-pigs. TheTibet mini-pigs have potential high reproductive ability. As long as if only the breedingmanagement changed, this potentiality may became actual productivity.This study demonstrates that B allele of ESR gene is helpful to improve TBN while had noinfaust effects on other economic traits. Thus, we can use ERS gene PCR-RFLP to MarkerAssisted Selection, which may get good heredity gaining.