Growth factors improve the proliferation of Jeju black pig muscle cells by regulating MyoD and growth-related genes

Background Jeju black pig (JBP), one of Korean native pig breeds, has excellent meat quality but grow slowly. The growth rate of pigs is related to differentiation and proliferation of muscle cells regulated by growth factors and expression of growth-related genes. However, few studies have determined the effect of growth factors on the proliferation of porcine muscle cells. Thus, the objective of this study was to establish optimal culture conditions of JBP muscle cells and determine the relationship of various factors involved in muscle growth with the proliferation of JBP muscle cells. Results We established a muscle cell line from JBP embryos and optimized its culture conditions. These muscle cells were positive for MyoD, but not Pax7. The proliferation rate of these muscle cells was significantly higher in a culture medium containing bFGF and EGF + bFGF than that without a growth factor or containing EGF alone. Treatment with EGF and bFGF significantly induced the expression of MyoD protein, an important transcription factor in muscle cells. Moreover, we checked changes of the expression of growth-related genes in JBP muscle cells by presence or absence of growth factors. Expression level of COL21A1 gene was changed only when EGF and bFGF were both added to culture media for JBP muscle cells. Conclusions Concurrent use of EGF and bFGF increased the expression of MyoD protein, thus regulating the proliferation of JBP muscle cells and the expression of growth-related genes.

Genetic Diversity and Ancestral Study for Korean Native Pigs Using 60K SNP Chip

The Korean native pig (KNP; Sus scrofa coreanus) is an indigenous porcine breed in South Korea considered as a valuable but dwindling genetic resource. Studies using diverse methodologies and genetic markers suggest that this population originated from the Manchu province of Northeastern China and migrated approximately 3000 years ago into the Korean peninsula. This study aimed to verify those findings by performing diversity and ancestral analyses using the 60K single-nucleotide polymorphism (SNP) BeadChip on 891 pigs of 47 breeds worldwide. We also performed principal component analysis (PCA), ancestry analyses, phylogenetic tree analysis using SNPhylo, and linkage disequilibrium analysis. Furthermore, we generated heatmap, obtained Nei’s genetic distance and FST values, and explored the heterozygosity of commercial and native Korean pigs. The results demonstrated that KNP pigs are more closely related to European breeds than to Chinese breeds. In addition, as previous studies have suggested, our admixture analyses indicated that KNP pigs showed distinguishable genetic structure.