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

摘要

The development of the small intestine (SI) is importantfor the health and growth of neonatal calves.This study evaluated the effect of arginine (Arg) andglutamine (Gln) supplementation and 2 levels of milkallowance on the histomorphological development ofthe SI in preweaning calves. Sixty mixed-sex Friesian× Jersey calves (3–5 d of age) were offered reconstitutedwhole milk (125 g/L, 26% fat, 26% protein) ateither high (20% of arrival body weight/d; HM) or low(10% of arrival body weight/d; LM) milk allowancewithout (Ctrl) or with supplementary Arg or Gln (at1% of milk dry matter) in a 2 × 3 factorial design (n= 10/treatment). After 35 d on the diets, all calveswere slaughtered to collect tissues for examination ofSI development. Calves in the HM group had highermilk intake, total weight gain, and average daily gaincompared with LM calves, but no effect of AA supplementationnor an interaction between milk allowanceand AA supplementation was observed. For the duodenum,we observed an AA by milk allowance interactionfor villus height and width, and goblet cell numberper villus (HM-Arg > HM-Gln > HM-Ctrl), and villusheight to crypt depth ratio (HM-Arg > HM-Gln= HM-Ctrl), but no effect of AA supplementation inthe LM group. Goblet cell numbers per 100 μm of SIwere greater in Arg-supplemented calves than in unsupplementedcontrols, with Gln-supplemented calvesintermediate to but not different from the other groups.Epithelium thickness was greater in LM than in HMcalves. Villus density, crypt depth, and muscle thicknessdid not differ between groups. For the jejunum,there was an AA by milk allowance interaction for villusheight, villus surface area, and villus height to cryptdepth ratio (HM-Arg = HM-Gln > HM-Ctrl), with noeffect of AA supplementation in the LM groups. Aminoacid supplementation affected goblet cell number pervillus (HM-Gln > HM-Ctrl calves, HM-Arg intermediate),and both LM-Arg and LM-Gln calves had greaternumbers than LM-Ctrl calves. Villus width, cryptdepth, and muscle thickness were greater in HM thanLM calves but there was no effect of AA supplementation.Villus density, goblet cell number per 100 μm ofSI, and epithelium thickness were unaffected by AAsupplementation and milk allowance. Milk allowanceand AA supplementation had no effect on SI morphologyin the ileum. Increasing milk allowance improvedvillus height, width, and surface area but only in ArgorGln-supplemented calves, not in control calves. Theobserved changes in development may be important forintestinal functionality, integrity, and barrier functionin preweaning calves, potentially through increased cellgrowth and proliferation or reduced levels of cellularatrophy.