A comparative proteomic analysis of blood serum for developmental stages in pigs

This study aimed to differentiate genes at developmental stages of pigs from 0 to 150 days of age, to build up a protein database and to find candidate genetic markers for growth traits. The analysis of two-dimensional electrophoresis and matrix-assisted laser-desorption/ionization mass spectrometry separated 252 protein segments. After successfully blasting the peptide sequences, the analysis confirmed 37 differentially expressed proteins that increased from birth to 150 days of age (type A), whereas the type B proteins presented the inverse pattern. The type C proteins included proteins that were expressed continuously throughout the developmental periods. A total of 319 primer sets for 33 genes were designed to find genetic variants using pooled DNA samples of Yorkshire pigs. Amplification products for all primer sets produced approximately 20 000 clones that were sequenced, and 48 candidate SNP sites were finalized for genotyping. A total of 475 animals were used for high throughput genotyping analysis. Among these, phenotype data of all 475 animals were collected for average daily gain, backfat thickness and days to 90 kg, whereas feed conversion data were collected for 300 animals and body measurement traits (starting weight, ending weight, body length, wither height and chest depth) were collected for 209 animals. Association analysis found significant statistical differences between the animals having genotypes of 13 SNPs (g.78935883C>T, g.147629986C>T, g.98266037T>C, g.214707340G>A, g.88350299C>T, g.17180956C>T, g.17181024C>T, g.2350283A>G, g.138361311C>T, g.44996379C>T, g.44996247A>C, g.107715245C>T, g.4149631C>T) for the various measured traits. The identified genetic polymorphisms, of which one was novel (g.214707340G>A), may serve as candidate molecular markers to change population means for the targeted growth traits.