The effect of arginine supplementation and milk allowance on small intestinal development in pre-weaning 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) or 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). After 30 days on the diets, all calves were slaughtered to collect tissues for examination of small intestine development. Small intestine development was enhanced through increasing villus growth at a higher supplementation (5.0 g/d), but not at a lower level of supplementation (2.8 g/d) of both Arg and Gln in the duodenum and jejunum. The resulting increase in surface area may be important to enhance intestinal feed digestion and nutrient absorption and, therefore, growth performance. The number of goblet cells was increased by the amino acid supplementation, positively influencing intestinal integrity which is important for gut barrier function and calf health. In summary, these results indicate that dietary Arg and Gln supplementation of pre-weaning calves enhanced intestinal functionality, integrity and barrier function in the small intestine either through increased cell growth/proliferation or reduced levels of cellular atrophy.