Effect of colostrum and milk on small intestine expression of AQP4 and AQP5 in newborn buffalo calves

• AQP4 immunoreactivity was differently distributed in the buffalo calf small intestine.
• AQP4 and AQP5 Western blot analysis showed different bands (28–60 kDa).
• PCR revealed the presence of AQP4 and AQP5 mRNAs in the buffalo calf small intestine.

Functional studies indicate differences in newborn gastrointestinal morphology and physiology after a meal. Both water and solutes transfer across the intestinal epithelial membrane appear to occur via aquaporins (AQPs). Given that the physiological roles of AQP4 and AQP5 in the developing intestine have not been fully established, the objective of this investigation was to determine their distribution, expression and respective mRNA in the small intestine of colostrums-suckling buffalo calves by using immunohistochemistry, Western blot, and reverse transcriptase-PCR analysis. Results showed different tissue distribution between AQP4 and AQP5 with the presence of the former along the enteric neurons and the latter in the endocrine cells. Moreover, their expression levels were high in the ileum of colostrum-suckling buffalo calves. The data present a link between feeding, intestinal development and water homeostasis, suggesting the involvement of these channel proteins in intestinal permeability and fluid secretion/absorption during this stage of development after birth.