Br J Nutr. 2009 Mar 9:1-7. [Epub ahead of print]
Supplemental zinc reduced intestinal permeability by enhancing occludin and zonula occludens protein-1 (ZO-1) expression in weaning piglets.
Zhang B, Guo Y. State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, People's Republic of China.
The present study was carried out to evaluate the pharmacological effect of Zn in diarrhoea in relation to intestinal permeability. Seventy-two weaning piglets, aged 24 d, were allocated to three dietary treatments: (1) control diet without supplemental Zn; (2) control diet supplemented with 2000 mg Zn/kg from ZnO; (3) control diet supplemented with 2000 mg Zn/kg from tetrabasic zinc chloride (TBZC). At the end of a 14 d experiment period, piglets were weighed, feed consumption was measured, and mucosal barrier function was determined using the lactulose/mannitol test. Expression of mucosal tight junction protein was measured at RNA and protein level. Inclusion of TBZC or ZnO in the diet significantly increased average daily gain (P < 0.01) and average daily feed intake (P < 0.05), while leading to reduced feed conversion ratio (P < 0.05) and faecal scores (P < 0.01). TBZC reduced urinary lactulose:mannitol ratios of weaning piglets (P < 0.05), while dietary supplementation with ZnO tended to reduce urinary lactulose:mannitol ratios (P = 0.061). ZnO or TBZC significantly enhanced the mRNA and protein expression of occludin (P < 0.05) and zonula occludens protein-1 (ZO-1) (P < 0.05) in the ileal mucosa. Piglets fed the TBZC-supplemented diet had a higher level of occludin than pigs fed the ZnO-supplemented diet (P < 0.05). The results indicate that Zn supplementation decreased faecal scores and the reduction was accompanied by reduced intestinal permeability, which was evident from the reduced urinary lactulose:mannitol ratios and increased expression of occludin and ZO-1. Therefore, the protective effect of pharmacological levels of dietary Zn in reducing diarrhoea might, at least partly, be associated with reduced intestinal permeability.
PMID: 19267955 [PubMed - as supplied by publisher]