Expression patterns of GHRL, GHSR, LEP, LEPR, SST and CCK genes in the gastrointestinal tissues of Tibetan and Yorkshire pigs

The aim was to characterize the expression patterns of several genes in the gastrointestinal tracts of Tibetan pigs (TP) and Yorkshire pigs (YP) and to explore their correlation with digestion and growth difference of the two breeds. The body weights and growth of YP and TP were studied at 6, 12 and 24 weeks of age, and their plasma levels of ghrelin (GHRL), leptin (LEP), somatostatin (SST) and cholecystokinin (CCK) were determined by enzyme linked immunosorbent assay (ELISA). Blood and gastrointestinal sections (stomach, duodenum, jejunum, ileum, caecum and colon) were collected and assayed for mRNA expression of the six genes (GHRL, ghrelin receptor (GHSR), LEP, leptin receptor (LEPR), SST and CCK) by reverse transcription-qPCR (RT-qPCR). TP generally had higher mRNA expressions of GHSR, LEP, LEPR, SST and CCK genes compared to YP, and expressed lower levels of the GHRL gene in most tissues of the digestive tract. In both breeds, plasma levels of the expressed proteins were more closely correlated with the feed intake and growth than with mRNA levels of the target genes. Our data indicate that TP possess special gene expression patterns in the gastrointestinal tract compared to YP, which is consistent with its unique feed intake and adaptation to harsh environment.