Diosmectite–zinc oxide promote intestinal health in early weaned pigs

The study evaluated whether feeding diosmectite–ZnO composite (DS-ZnO) at 500mg Zn/Kg to early weaned pigs would alleviate the weaning-related intestinal disorders as a substitute for high concentration of ZnO (2250mg Zn/Kg). Pigs weaned at an age of 21 ± 1 day were allotted to four treatments groups as follows: (1) control; (2) DS-ZnO, 500mg Zn/Kg diet; (3) ZnO, 2250mg Zn/Kg diet; and (4) mixture of 2,.0g DS/Kg and 500mg Zn/Kg from ZnO (equal amount of DS and ZnO in the DS-ZnO treatment group). The feeding experiment lasted for 14 days. Average daily gain, feed intake and gain:feed ratio were calculated from days 0 to 7 post-weaning and 7 to 14 post-weaning. The faecal score of each piglet in a pen was recorded individually every day and the average scores per pen were calculated daily.

The results showed that, compared with the control on days 7 and 14 post-weaning, addition of DS-ZnO at 500mg 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 4kDa 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- a, IL-6 and interferon-g (IFN-g) on day 7 post-weaning were also decreased (P<0.05). The piglets fed DS-ZnO at 500mg Zn/Kg did not differ in the above parameters from those fed ZnO at 2250mg Zn/Kg, while they had better performance than those fed the mixture of DS and ZnO. Supplementation with DS-ZnO at 500mg Zn/Kg was effective in alleviating diarrhoea, barrier dysfunction and inflammatory cytokine expression and up-regulating tight junction protein expression. Overall, the results demonstrated that the weaned piglets fed DS-ZnO at 500mg Zn/Kg did not differ in growth performance, post-weaning diarrhoea and intestinal barrier function from those fed ZnO at 2250mg Zn/Kg, while they had better performance than those fed the equivalent amount of mixture of DS and ZnO.

Dietary inclusion of DS-ZnO at 500mg Zn/Kg may alleviate diarrhoea and improve intestinal barrier function by down-regulation of pro-inflammatory cytokines and up-regulation of tight junction proteins.