| The development of domestic animal and poultry industry depends on not only the advancement of breeding, but also the demand of the consumption market. In recent year, people had made a great of progress in duck breeding, but this kind of high strength selection pursued upper efficiency of feed utilization, growth velocity and meat factor, ignored the meat quality such as flesh color, smell and taste of meat. Meanwhile, in our country, people's requirement about meat was going through a change from he quantity to the quality, and the slowly promotion of duck meat was not satisfied with the requirement of people, thus affected the growth of duck meat consumption, leading lots of inimicable influence to the development of duck industry. Therefore, the improvement of duck meat quality is extremely urgent now. Cherry Valley duck, Sumu duck, White Muscovy and Jingding duck were detected in this study, analyzing the discipline of early growing development and discrepancy of meat quality indexes. Then cloned partial sequence of duck A-FABP (Adipocyte Fatty Acid-Binding Protein) gene, studied the genetic diversity of partial A-FABP gene by technique of PCR-SSCP confirmed by sequencing and the studied the association of polymorphisms of A-FABP gene with fat traits in ducks. The results showed as followed.1. The early bodyweight of Cherry Valley duck, White Muscovy, Sumu duck and Jingding duck were measured, three nonlinear curves of Logistic, Von Bertalanffy and Gompertz model were used to fit the growth curve in this study. The results showed that Gompertz model generated the best effect. Further more, the fitting parameters of 4 groups fitted by Gompertz model were compared, and results indicated that the inflection age of Cherry Valley duck, Sumu duck and Jingding duck was about 3 weeks and White Muscovy was about 6 weeks. The growth peak of them was the same to the inflection age and the rest of fitting parameters were in accord with their germplasm characteristic.2. The conventional indicators of chest muscle and serum triglyceride content, cholesterol content were difference between groups, and there was no unified egularity. The correlativity of pH value with percentage of loss water, tender, meat color, intramuscular fat (IMF), triglyceride (TG) content and cholesterol (TC) content showed that there were no extremely significant correlation within 4 duck goups separately, excepted extremely significant negative correlation between pH value and percentage of loss water and positive correlation between pH value and meat color in Jingding duck group.The overall correlation coefficient analysis showed there wad only cholesterol content had extremely significant correlation. The correlativity of IMF with other indicators showed only TC content had significant correlation in White Muscovy, and had no significant correlation within other groups, but the overall correlation coefficient analysis showed the percentage of loss water, tender, meat color, TG content had significant correlation with IMF excepted pH value and TC content, showing the IMF had a basilic influence on meat quality traits.3. A pair of primers P-in1 were designed to amplified duck A-FABP intron-1, then we cloned it and submitted it to GenBank (GenBank accession number: FJ536257). The duck A-FABP intron-1 gene was 1436bp in length, and the homology was 75.1% compared with chicken A-FABP intron-1 gene, then five pairs of primers were designed according to sequence compared and spliced and analyzed by SSCP. Three, six and four nucleotides mutation were found in the products of primer P1, P3 and P-intron2, which resulted in 3, 8 and 3 genotypes, separately. The allele C was dominant allele in Cherry Valley duck, Sumu duck and Jingding duck in P1 locus; allele B in Cherry Valley duck and allele C in Sumu duck and Jingding duck were dominant allele separately and the allele D was only distribution in Jingding duck. In P-intron2 locus, the dominant allele in Cherry Valley duck was allele G, and other two groups were allele H. The results of Chi-Square test showed that Cherry Valley duck and Sumu duck deviated from the Hardy-Weinberg equilibrium (P<0.01) except Jingding duck in P1 locus, and all of the three groups fit with it in P3 and P-intron2 loci (P>0.05). Genetic analysis showed the effective number of alleles, heterozygosity and PIC in Cherry Valley duck and Sumu duck were higher than Jingding duck in these there loci. Analyzed the correlation of the fat traits with the genotypes of these three loci in different duck groups, the results showed the fat traits had no significant difference in different genotypes in Sumu duck groups, but the TC content in Cherry Valley duck and TG content in Jingding duck were significantly different in different genotypes in P3 locus. These results showed polymorphisms of A-FABP gene had influence on fat traits to a certain degree.4. A-FABP intron-1 gene was amplified by primer P-in1 using White Muscovy, then we cloned it and submitted it to GenBank(GenBank accession number: FJ763338). The Muscovy A-FABP intron-1 gene was 1456bp in length, and the homology were 94.43% and 75.1% compared with duck and chicken A-FABP intron-1gene, and existed many multiple mutations, insertion and deletion compared with duck. Five pairs of primers were used to analyzed by SSCP. T-G at 1074 and A-C at 1089 nucleotide mutation were found in the products of primer P3, which resulted in 3 genotypes and the allele A was dominant allele. The results of Chi-Square test showed that the groups fit with the Hardy-Weinberg equilibrium (P>0.05). Genetic analysis showed the PIC was at a moderate polymorphism. Analyzed the correlation of the fat traits with the polymorphism, showed the IMF of AA genotype bird was significant higher than AB and BB genotype bird. This result showed the polymorphisms of A-FABP gene had a basilic influence on fat traits.
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