Effect of single nucleotide polymorphisms in HSP70 and avUCP genes on semen quality traits during chronic heat stress and production traits under normal environmental temperature in chickens

• Main Authors: Lin-Liang Peng, 彭麟量
• Other Authors: San-Yuan Huang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/28094317885140978548

碩士 === 國立中興大學 === 動物科學系所 === 101 === Heat stress causes major economical loss of poultry industry in tropical/subtropical area. Heat stress can result in high mortality, low growth performance, low egg production and reproduction disorders in roosters or hens. Heat-shock protein 70 (HSP70) is a molecular chaperone that can help cells to overcome heat stress. Avian uncoupling protein (avUCP) is known to play a role in regulating reactive oxygen species production in mitochondria. HSP70 and avUCP may be potential markers for thermotolerance in chickens. The purposes of this study were to investigate the effect of single nucleotide polymorphisms (SNPs) in HSP70 and avUCP on semen quality traits of roosters under chronic heat stress and on production related traits under normal environmental temperature. Experiment 1 used 55 31-week-old F2 reciprocal crossbred chickens between Rhode Island Red selected for low residual feed consumption and L2 strain Taiwan country chicken. Roosters received four weeks of 32°C, 55% relative humidity chronic heat stress and the semen quality traits were evaluated weekly. The SNPs of HSP70 and avUCP were analyzed by PCR-RFLP. The result indicated that CG genotype in HSP70-C276G had higher sperm concentration than GG genotype after one week of heat stress (P<0.05). But GG genotype had the best sperm morphology after one week of heat treatment (P<0.05). After two and three week of heat stress, the EE genotype in avUCP-T1316C had higher sperm concentration. In Experiment 2, 562 F2 of reciprocal crosses chicken XL strain and 179 XR strain were used (XL: ♂L2R-×♀R-L2；XR: ♂R-L2×♀L2R-). The body weight, egg production and antibody response to sheep red blood cell (SRBC) were collected. The genotypic frequencies of CC, CG, and GG genotypes at HSP70-C276G gene were 46.0%, 40.9%, and 13.1% in XL male, 37.6%, 48.7%, and 13.7% in XL female, 43.3%, 46.7%, and 10.0% in XR male, and 32.6%, 59.6%, and 7.9% in XR female. The genotypic frequencies of EE, EF, and FF genotypes at avUCP-T1316C gene were 39.5%, 50.9%, and 9.6% in XL male, 44.3%, 40.6%, and 15.1% in XL female , 71.1%, 27.8%, and 1.1% in XR male, 62.9%, 37.1%, and 0% in XR female. There were significant difference in avUCP-T1316C genotypic frequencies among XR and XL. Mutation site at 1270 C > T in avUCP gene did not show polymorphism in this study. In XR female, GG genotype of HSP70-C276G had higher 8 wk body weight than CG genotype. There were no significant genotypic effects on XL male, XR male and XR female. In XL strain male, the CG genotype had better performance than GG genotype in body weight gain between 4 to 8 wk (P<0.05). For avUCP-T1316C, the genotype effects mainly affect XL female population. FF genotype had higher 4, 8 and 12 wk body weight and higher body weight gain between 0 to 4 and between 4 to 8 wk in XL strain female. There was no significant effect of SNP in HSP70-C276G and avUCP-T1316C on egg production trait. However, HSP70-C276G polymorphism might affect the laying habits in XL. In immune response to SRBC, the CG genotype had higher antibody response to SRBC at day 14 than CC genotype in XL male (P<0.05). In females of XR and XL strain, the GG genotype showed better antibody response to SRBC at day 14 and day 7 respectively (P<0.05). The EF genotype of avUCP had higher antibody response to SRBC at day 14 in XL male. But in XL female, EF had lower antibody response to SRBC at day 14. In summary, the results of this study indicated that the GG genotype in HSP70-C276G had better sperm morphology and avUCP-T1316C seem to have an effect on sperm concentration during chronic heat stress. But the potential effect of these SNPs on thermotolerance requires further studies. For growth performance, egg production, and immuno function, the effects of genotypes differed among strain and between gender. Therefore, practical application of SNP in these two genes as selection markers needs further evidences.