| In this study, breeding index on growth performance, slaughter traits and flavoring compounds content of Shengyu Pigeon were determined, and MSTN was used as candidate gene for the Polymorphism analysis by PCR-SSCP.Based on the results of relationships between molecular markers and growth performance and flavoring compounds concerned, candidate molecular markers were classified that can provide theoretical foundation for molecular assistant breeding. Through collaborative analysis, differentiation of MSTN expression in different tissues was detected by Real-time PCR technology. Main results and conclusions formed in this study were as fellows:1. Fitting of growth curve and collaborative analysis of slaughter traits in Shengyu pigeonsUsing Logistic, Gompertz growth curve models to fit Shengyu Pigeon body weight changes from hatched to 25-day-old. Two kinds of curve fitting models all had high degree of fitting, both more than 0.99, among which the fitting goodness of Logistic reached up to 0.99967, Gompertz model goodness of fitting also reached the level of 0.99938, Logistic model was more in line with real growth pattern of Shengyu Pigeon Regression analysis of slaughter traits showed that determination coefficients of chest depth and oblique body length towards carcass weight reached 76.6%, that of keel length towards lean meat weight was up to 53.5%.2. Contents of flavoring compounds in Shengyu pigeons muscleContents of intramuscular fat, saturated fatty acids, mono-unsaturated fatty acids and poly-unsaturated fatty acids were almost equal, counting on 2.15%,35.6 %,31.3% and 33.1%,respectively. C18. C16 and C20 consisted the majority of fatty acids with the contents of 62.36%,24.24%,10.23%. Essential amino acids covered the percentage of 28.51%, with lysine, isoleucine, leucine amino acid, threonine, methionine at its high level, and content of flavor amino acid was as high as 43.3%.3. MSTN gene cloning and sequence analysisMSTN gene cDNA obtained by thorax muscle RT-PCR amplification, connected with pMD19-T Vector and then transferred into DH5aE.coli competent cells, identified by PCR and double restriction enzyme digestion, sequencd full-length of 1128bp. Sequence homology coefficients between pigeon and human, mouse and chicken were 86%,92%and 98%.Comparing with MSTN sequence of chicken, that of Shengyu pigeon had multiple deletions and insertions which may lead to changes in protein structure.4.Relation between polymorphism of MSTN and production performance of Shengyu PigeonsMSTN SNPs were detected by PCR-SSCP analysis. P1 and P4 of four pairs of primer created polymorphism, with two kinds of genotypes. The frequency of Gene A and B at the locus PI were 0.8375 and 0.1625, respectively. The frequency of Gene C and D at the locus P4 were 0.9875 and 0.0125, respectively. PIC of those two loci was at low polymorphic, at 0.2352 and 0.0008. Collaborative analysis between the MSTN SNPs and body weight, body size, shape, meat texture and flavor substances showed that thorax width of genotype AA was significantly higher than that of genotype AB, Oblique body length and keel length of genotype AB were remarkably higher than those of AA, no significant difference in other indicators indicatd that MSTN gene can be used as candidate gene for body size.5 Differentiation expression of MSTN gene in different tissuesExpression differentiation research by real-time PCR and collaborative relationship between gene MSTN and growth performance showed that:MSTN gene expression in the liver was the highest, followed by brain tissue, but low in muscle.The results also proved the conclusion that the animal muscle growth rate was negatively related to MSTN expression; but levels in various tissues were not significantly correlated to body weight in early age (P> 0.05). |
