Effect of arginine or glutamine supplementation and milk feeding allowance on small intestine development in calves

The development of the gastrointestinal tract plays a key role in the health and growth of neonatal calves. The present experiment was designed to evaluate the effects of arginine (Arg) and glutamine (Gln) supplementation and two levels of milk allowance on the organ and histomorphological development of the small intestine in pre-weaning calves. Sixty mixed-sex Friesian × Jersey calves (3-5 days of age) were offered whole milk powder (125 g/L, 26% fat, 26% protein) at either high (20% of arrival BW) or low (10% of arrival BW) milk allowance without or with Arg or Gln (at 1% of milk DM) in a 2 × 3 factorial design. After 35 days on the diets, all calves were slaughtered to collect tissues for examination of small intestine development. Villus height, width, and surface area was enhanced in calves offered high milk volumes supplemented with either Arg or Gln in the duodenum and jejunum (P<0.001), with a similar trend (P=0.08) in the ileum, but was unaffected by milk allowance. The resulting increase in surface area of the intestine may be important to enhance intestinal feed digestion and nutrient absorption. The number of goblet cells in the duodenum and jejunum was increased by both Arg- and Gln-supplementation, positively influencing intestinal integrity which is important for gut barrier function and calf health. In summary, these results indicate that dietary supplementation of the milk with Arg or Gln enhanced intestinal functionality, integrity, and barrier function in the small intestine of pre-weaning calves either through increased cell growth/proliferation or reduced levels of cellular atrophy.