Abstract:

The aim of the study was to investigate the expression of bovine peptide transporter I(bPepTI) mRNA in bovine Gastrointestinal(GI) tract. Relative and absolute quantitative mRNA methods were used to detect the expression of bPepTI mRNA in different parts of bovine gastrointestinal tract and to investigate its main absorption sites in the present study. Both the -ΔC_t and standard curve methods were used in relative quantification. The results of -ΔC_t method revealed no significant difference among different parts of bovine GI tract (P>0.05). Numerically, mRNA expression of bPepTI decreased in order of reticulum < omasum < abomasums < colon < rumen < duodenum< caecum< ileum< jejunum. The results of standard curve method were significantly different among different parts of bovine GI tract (P<0.05). mRNA expression of bPepTI in jejunum was significantly higher than that in ileum (P<0.05); the expression of bPepTI in ileum was significantly higher than that in other parts (P<0.05); and there were no significant differences among the other parts of bovine GI tract (P>0.05). The data from absolute quantification showed that mRNA copies of bPepTI were different in different parts of bovine tract (P<0.05), and the order from the highest to the lowest mRNA copies of bPepTI was jejunum,omasum, reticulum, rumen, caecum, duodenum, ileum, abomasums and colon. mRNA copies of bPepTI in jejunum was significantly higher than that in omasum (P<0.05), and there was no significant differences among caecum, duodenum, ileum, abomasum (P>0.05). In conclusion, results of standard curve and absolute quantification method were more believable,and jejunum, ileum, omasum and rumen may be the major absorption parts of small peptides along bovine GI tract, in which there were high mRNA expression of bPepTI.