Effects Of Isobutyrate On Rumen, Small Intestine Mucosal Morphology And Expression Of Function Gene In Calves

Forty-eight Chinese Hostein bull Calves about45day after birth with similar birth weight were chosen and divide into four groups and supplemented with four concentrations (0,3,6and9g/d) of isobutyrate to evaluate the effccts of different level isobutyrate on rumen mucosal morphology, small intestine mucosal morphology and expression of function gene of Calves. The calves were slaughtered on45d,60d,90d and120d after birth. Histomorphology of five parts of rumen (including dorsal sac, anterior dorsal blind sac, posterior dorsal blind sac, anterior ventral blind sac and posterior ventral blind sac) and four parts of small intestine (including duodenal mucosal, proximal jejunal mucosal, distal jejunal mucosal and ileal mucosal) were observed by means of paraffin method. The results showed that the rumen wall thickness, papillae length, papillae width, keratinized layer thickness, wall thickness, mucosal thickness, villus length and crypt depth were increased companied with the growth of calves (P<0.05). All items of rumen and small intestine in groups supplemented isobutyrate at6g/d and9g/d were higher than that of in group supplemented isobutyrate at3g/d and control group significantly(P<0.05), while no significant differences were found between groups supplemented isobutyrate at6g/d and9g/d (P>0.05). The scanning electron microscopy results showed the growth of rumen and small intestine were increased with the growth of calves. The development of papillae of rumen and villus of small intestine in group supplemented isobutyrate at6g/d group were superior to control group. The expression of function gene were compared by determining the mRNA abundances of GHR, INSR, HMGCL1, SGLT1in different parts of rumen and small intestine with quantitative real-time PCR. The expression of GHR, INSR, HMGCS1and SGLT1were increased with the growth of calves in digestive system. The expression of GHR in groups supplemented isobutyrate at6g/d and9g/d were higher than that of in group supplemented isobutyrate at3g/d group and control group significantly (P<0.05), while no significant differences were found between groups supplemented isobutyrate at6g/d and9g/d (P>0.05). The expression of INSR of rumen and small intestine in group supplemented isobutyrate at6g/d was superior to control group and groups supplemented isobutyrate at3g/d and9g/d. The expression of HMGCS1of different parts of rumen in group supplemented isobutyrate at6g/d was superior to control group. The expression of SGLT1in groups supplemented isobutyrate at6g/d and9g/d were higher than that of in group supplemented isobutyrate at3g/d significantly (P<0.05). These results indicated that the optimum dose of isobutyrate was6g/d.