Production Performance Of Tibetan Chicken And Isolation,SNPs Detection Of Three Chicken Genes And Their Association With Economic Traits

Tibetan chicken mainly distributed in Tibetan altiplano, is a rare and excellent chicken breed in China. It has many unique characteristics, such as cold resistance, strong disease resistance, anoxia resistance, delicious meat quality, good officinal value, extensive cultivation and good fancy. At the same time, it has the disadvantage of low growth rate and poor laying performance. How to improve the flaw of Tibetan chicken with un-affecting its virtue for cultivating new Tibetan chicken by introductive crossing, and how to exploit and utilize the Tibetan chicken by economic crossing is an important study task in current.This study is based on the item of National Ministry of Agriculture (948). According to the study actuality of Tibetan chicken, overseas excellent breed was introduced for crossing the Tibetan chicken; In addition., using the information of Full-length cDNA bank and candidate gene strategy, some new genes with important economic performance were cloned and separated by bioinformatics and biotechnology, which could have the basic for searching the molecular assistant marker. The main results are as follows:1. Comparing analysis the laying performance of Tibetan chicken (TC), Recessive White chicken (RW) and F1 (Tibetan chicken♂×Recessive White♀, TR), the egg production,egg weight of the TR with 64 weeks age has significant improvement comparing with TC (P < 0.05). At the same time, the early development of TC, RW, TR and 75%TC (Tibetan chicken♂×♀F1♀) was compared, the result showed TR had good body weight, weekly gain weight and shank length comparing with TC and 75%TC and represent significant level (P < 0.05).2. The growth curve of Tibetan chicken from 0 to 16 weeks old was analyzed and fitted with three kinds of nonlinear models (Gompertz, Logistic, von Bertalanffy). The result showed that the growth curves could be well fitted with three models, but the Gompertz model had the best effect on fitting with the growth curves.3. According to the information of Full-length cDNA library of Tibetan chicken leg muscle and candidate gene strategy, the Full-length cDNA sequence of Myotilin (MyoT) was isolated and identified, and the fragments of Calcium channel voltage-dependent gamma subunit 1 (Cacngl), Calcium/calmodulin-dependent protein kinase II delta 2-subunit (Camk2d) through the PCR amplification. Combining with chicken genome information, the amino acid sequence and protein structure of three genes were analyzed4. Seven polymorphic sites of AfyoT,Cacngl and Camk2d were detected respectively and a long fragment indel polymorphism was detected in the intron 2 of Cacngl by PCR-RFLP, mpPCR and M-ASP. The allele frequencies and genotype frequencies were analyzed in different populations and the distribution difference of genotype was analyzed.5. The associations between genotypes and phenotypes of economic traits of the above polymorphic sites were analyzed in the experimental chicken population constructed under the cooperation of our lab and Tibet Agriculture and Animal Husbandry College. The result showed:①There are significant associations between the genotype of Hin6Ⅰpolymorphie site at exon 10 of MyoT with phenotypes of leg muscle weight, leg muscle weight rate, Eviscerated rate and color of leg muscle (P＜0.05); there are significant associations between the genotype of RsaⅠpolymorphic site at 3'-UTR of MyoT with phenotypes of carcass weight and subcutaneous fat thickness (P＜0.05); there are significant associations between the genotype of BsuRⅠpolymorphic site at 3'-UTR of MyoT with phenotypes of carcass weight, intermuscular fat width, semi-eviscerated weight and eviscerated weight (P＜0.05);②There are significant assoeiatious between the long fragment indel polymorphie site in intron 2 of Cacng1 with phenotype of tenderness (P＜0.01); there are significant associations between the genotype of MspⅠpolymorphic site at exon 4 of Cacng1 with phenotypes of tenderness and color of leg muscle (P＜0.05); there are significant associations between the genotype of M-ASP polymorphic site at exon 5 of Cacng1 with phenotypes of liver weight, drip loss (P＜0.05) and color of breast muscle (P＜0.01); there are significant associations between the genotype of MspⅠpolymorphie site at 3'-UTR of Cacng1 with phenotypes of color of leg muscle (P＜0.05) and there has current correlation between this polymorphie site with phenotypes of drip loss;③There are significant associations between the genotype of VspⅠpolymorphie site at exon 15 of Camk2d with phenotypes of Abdominal fat weight (P＜0.01) and pH value (P＜0.05).6. The semi-quantitative RT-PCR was performed to detect the expression pattern of chicken MyoT and Cacng1 gene in different tissues (heart, liver, spleen, lung, kidney, brain and muscle). The result showed MyoT gene was expressed in heart and muscle and Cacng1 gene was expressed in heart, liver, kidney, brain and muscle. Next, the mRNA expression level was analyzed. The result revealed the expression level of heart was higher than muscle in MyoT, and the expression level of muscle was highest in Cacng1, next was heart, kidney, brain, the lowest expression level was liver.