Effects of age and zinc supplementation on transport properties in the jejunum of piglets

Abstract

Zinc is effective in the prevention and treatment of post-weaning diarrhoea and in promoting piglet growth. Its effects on the absorption of nutrients and the secretory capacity of the intestinal epithelium are controversial. We investigated the effects of age, dietary pharmacological zinc supplementation and acute zinc exposure in vitro on small-intestinal transport properties of weaned piglets. We further examined whether the effect of zinc on secretory responses depended on the pathway by which chloride secretion is activated. A total of 96 piglets were weaned at 26 days of age and allocated to diets containing three different levels of zinc oxide (50, 150 and 2500 ppm). At the age of 32, 39, 46 and 53 days, piglets were killed, and isolated epithelia from the mid-jejunum were used for intestinal transport studies in conventional Ussing chambers, with 23 μm ZnSO4 being added to the serosal side for testing acute effects. Absorptive transport was stimulated by mucosal addition of d-glucose or l-glutamine. Secretion was activated by serosal addition of prostaglandin E2 , carbachol or by mucosal application of Escherichia coli heat-stable enterotoxin (Stp ). Jejunal transport properties showed significant age-dependent alterations (p < 0.03). Both absorptive and secretory responses were highest in the youngest piglets (32 d). The dietary zinc supplementation had no significant influence on jejunal absorptive and secretory responses. However, the pre-treatment of epithelia with ZnSO4 in vitro led to a small but significant decrease in both absorptive and secretory capacities (p < 0.05), with an exception for carbachol (p = 0.07). The results showed that, in piglets, chronic supplementation with zinc did not sustainably influence the jejunal transport properties in the post-weaning phase. Because transport properties are influenced by the addition of zinc in vitro, we suggest that possible epithelial effects of zinc depend on the acute presence of this ion.

Effect of Long-Term and Short-Term Imbalanced Zn Manipulation on Gut Microbiota and Screening for Microbial Markers Sensitive to Zinc Status

“…Nevertheless, the amounts of Zn consumed often exceed well-established nutritional requirements ( 7 – 9 ). Recent studies reported that Zn overdose exposure can have deleterious consequences, such as decreasing immune function, altering intestinal absorptive and secretory capacity, or increasing visceral adiposity ( 10 – 12 ).…”

Paracellular Filtration Secretion Driven by Mechanical Force Contributes to Small Intestinal Fluid Dynamics

“…Regulation of fluid movement through the small intestine epithelium is of physiological interest and clinical relevance. We selected zinc as a candidate inhibitor of fluid flow because of its purported antidiarrheal properties [ 22 , 23 , 24 , 25 , 26 ] and influence on epithelial tight junction integrity and ion secretion [ 27 , 28 , 29 , 30 , 31 ]. Fluid flow by cultured enterocytes exposed to vigorous aeration was first measured for 5 min without zinc to obtain a baseline rate of flow.…”

Effects of Zinc Sources and Levels on Growth Performance, Zinc Status, Expressions of Zinc Transporters, and Zinc Bioavailability in Weaned Piglets

“…In the present study, the results showed that CS–Zn or ZnSO 4 both increased the expression of zinc transporter protein, and the expression of zinc transporter protein increased linearly with supplemental zinc. ZnT1 is distributed on the basolateral membrane of enterocytes; the function of ZnT1 is to transport excess intestinal zinc into extracellular matrix or organelles for the sake of reducing the zinc level of cytoplasm [ 25 ]. Increased zinc concentrations significantly elevated intestinal ZnT1 mRNA and protein expression [ 26 ].…”