Diosmectite-zinc oxide composite improves intestinal barrier function, modulates expression of pro-inflammatory cytokines and tight junction protein in early weaned pigs

The study evaluated whether feeding diosmectite-ZnO composite (DS-ZnO) at 500 mg Zn/kg to early weaned pigs would alleviate the weaning-related intestinal disorders as a substitute for high concentration of ZnO (2250 mg Zn/kg). The pigs weaned at an age of 21 +/- 1 d were allotted to four treatments groups as follows: (1) control; (2) DS-ZnO, 500 mg Zn/kg diet; (3) ZnO, 2250 mg Zn/kg diet; and (4) mixture of 2.0 g DS/kg and 500 mg Zn/kg from ZnO (equal amount of DS and ZnO in the DS-ZnO treatment group). The results showed that, compared with the control on days 7 and 14 post-weaning, addition of DS-ZnO at 500 mg Zn/kg improved (P<0.05) daily gain and feed intake, decreased (P<0.05) post-weaning scour scores, increased (P, 0 . 05) jejunal villus height and the ratio of villus height and crypt depth, decreased (P<0.05) jejunal paracellular permeability of fluorescein isothiocyanate dextran 4 kDa and up-regulated (P<0.05) tight junction protein expression of occludin, claudin-1 and zonula occludens-1 in jejunal mucosa. The mRNA levels of TNF-alpha, IL-6 and interferon-gamma (IFN-gamma) on day 7 post-weaning were also decreased (P<0.05). The piglets fed DS-ZnO at 500 mg Zn/kg did not differ in the above parameters from those fed ZnO at 2250 mg Zn/kg, while they had better performance than those fed the mixture of DS and ZnO. Supplementation with DS-ZnO at 500 mg Zn/kg was effective in alleviating diarrhoea, barrier dysfunction and inflammatory cytokine expression and up-regulating tight junction protein expression.