Polymorphism Of IGF-1 And Pit-1 Gene And Its Association With Growth Traits In New Line Of Huai Pig

IGF-1 (insulin-like growth factor-1) is an important factor by regulating animal body growth, development and metabolism, and IGF-1 plays a major role in promoting growth by mediated growth hormone. Pit-1 (pituitary specific transcription factor-1) is an important factor by regulating gene transcription in pituitary cells, and Pit-1 plays an important role in regulating animal growth, development and reproduction through regulating growth hormone gene, prolactin gene and thyroid stimulating hormoneβsubunit gene expression. In this study, we take the first and the second generation from new line (Ⅱ) of Huai pig as experimental material, using PCR-RFLP technique to detect IGF-1 gene and Pit-1 gene polymorphisms and analyse its association with growth traits, in order to explore to improve growth traits of pig by using marker-assisted selection, and provide a theoretical basis to speed up cultivate new line of Huai pig. Meantime, we study the effect of generation selection through compare with growth traits of the first and the second generation from new line (Ⅱ) of Huai pig. The results show that:1,By detecting the first and the second generation from new line (Ⅱ) of Huai pig, both the IGF-1 gene at HhaI site and Pit-1 gene at RsaI site exist polymorphisms. It is showed that the genotype distribution of the two genes are on Hardy-Weinberg equilibrium in the two generations by chi-square test.2,The first generation, the second generation and the merger of two generations from new line (Ⅱ) of Huai pig , the AA genotype of IGF-1 gene on average daily gain during growth, adjusted age up to 90kg has the trend better than the AB, BB genotype, but the difference was not significant (P>0.05); the DD genotype of Pit-1 gene has the trend better than the CD, CC genotype, but the difference was not significant (P>0.05). The merger of two generations, the AA genotype of IGF-1 gene, the DD genotype of Pit-1 gene has the thinnest adjusted backfat thickness up to 90kg, but the differences were not significant (P>0.05) when compare with other different genotypes. If taken IGF-1 gene and Pit-1 gene as genetic markers of growth traits for breeding new line of Huai pig, it needs to further validate in the next generation and expand sample size in new line (Ⅱ) of Huai pig.3,The second generation of growth traits are improved than the first generation from new line (Ⅱ) of Huai pig through selecting the two generations. The average daily gain increased from 647.92g/d to 651.62g/d during growth, but the difference was not significant (P>0.05); adjusted day up to 90kg significantly decreased from 203.43d to 192.52d (P<0.05); adjusted backfat thickness up to 90kg significantly decreased from 12.82mm to 11.72mm (P<0.05), it shows that the growth traits of pig can be improved through generation selection.