Studies On The Induced Differentiation Of Porcine Preadipocytes And The Polymorphism Of13Pig Breeds Using AFLP Markers

We studied the induced differentiation of porcine preadipocytes and the polymorphismgenetic relationship of13pig breeds using AFLP markers in this thesis.Fatty deposition is an important economical trait in pig breeding, and it has been shownto be closely related with the pork quality. Preadipocytes are a type of special precursor cellswith the ability of generation and differentiation towards adipocytes whose deeply study ofmechanism of generation and cell differentiation is useful to comprehend regulationmechanism of fatty deposition in cells. Laiwu Black is a superordinate indigenous pig breed,which have the highly capable of fatty deposition, and have the abundant intramuscular fat.In this study, preadipocytes were isolated from subcutaneous adipose tissue of1daypiglet by the combination of collagenase and trypsin digestion and were successfully primaryand subculturing cultured. We studied the preadipocytes induced differentiation culture, anddetected the expression of the important transcription factor PPAR γ in the process ofpreadipocytes differentiation. The result showed that the isolated cells started adherence at8hafter initiation of primary culture and displayed short spindle shaped or irregular triangle. On3rd day, the cells entered logarithmic growth phase, displayed fibroblast-like, and the cellsgrowth showed S shape. The induction result showed that fat droplets occurred in smallamount of cells on2nd day, in large amount on3rd day, those small fat droplets graduallyconverged into big ones from7th to8th day, and on the12th day, become to one big fatdroplets, the adipocytes dyed jacinth by oil red O, the PPAR γ mRNA levels graduallyincreased in the process of the preadipocytes differentiation, and up to top at the48h afterinduced differentiation culture, then the PPAR γ mRNA levels gradually decreased. From theabove all results suggested that we successfully established the Laiwu Black primary culturesystem and the model of the induced differentiation in vitro. This study laid the basis forfurther research Laiwu Black adipocyte proliferation, differentiation and porcine fatdeposition. AFLP markers were used to analysis the genetic diversity of the13pig breeds. GenomicDNA of pigs was amplified with12E+3and T+3primer combinations We got the geneticsimilarity and the dendrogram used the UPGMA method of the13pig breeds. The resultshowed that the total polymorphic loci were76which had a proportion of41.99%. Thenumber of the observed alleles was from1.6056to1.2899, and the mean number of observedalleles was1.4632. The number of the effective alleles was from1.4282to1.2050, and themean number of effective alleles was1.3276. The mean Nei’s gene diversity (H) was0.1919,and the Shannon’s information index (I) was0.2799. The13pig breeds can be classified intotwo large groups after cluster analysis based on the UPGMA (unweighted pair group methodarithmetic average) method. Chinese indigenous pig breeds have far relationship withimported pig breeds. The relationship in Chinese indigenous pig breeds was closer. The firstmajor group was composed of Duroc, Large White and Landrace. The second major groupwas composed of Meishan, Erhualian, Huainan, Laiwu Black, Dpulian, Licha Black,Dongbeimin, Yantai Black, Ymeng Black and Tuhe Black, and this group was divided intothree subgroups, the first group was composed of Dongbeimin and Licha Black; the secondgroup was composed of Yantai Black, Dapulian, Tuhe Black, Yimeng Black and Laiwu Black;the third group was composed of Huainan, Meishan an Erhualian.