Abstract:

This experiment was conducted to evaluate the effects of various concentrations of coated ZnO on diarrhea index and intestinal morphology of weaned piglets. A total of 72 crossbred (Duroc×Landrace×Yorkshire) weaned piglets were allotted randomly, on initial BW((7.72±0.65)kg), to six groups with 4 replicates per group and 3 pigs per replicate in a completely randomized design for 28 days. Groups consisted of a low-zinc control group (LZ) fed 250 mg·kg^-1 Zn of diet as ZnO, a high-zinc control group (HZ) fed 2 250 mg·kg^-1 Zn of diet as ZnO (during 15-28 d, Zn concentration of HZ reduced to 250 mg·kg^-1) and 4 experimental groups in which coated ZnO was added at 250, 380, 570 and 760 mg·kg^-1 Zn of basal diet, respectively. The results showed as follows: 1) In 1-14 days, adding 380 and 570 mg·kg^-1 coated ZnO significantly decreased diarrhea index (P<0.05), and which had no significant differences with that of HZ；the diarrhea index, adding 510 mg·kg^-1 Zn of basal diet, was the lowest. 2) No significant increase in liver and kidney Zn concentrations were observed between groups adding 250, 380, 570 and 760 mg·kg^-1 coated ZnO (P>0.05); adding 380, 570 and 760 mg·kg^-1 coated ZnO significantly increased fecal Zn concentrations (P<0.05). 3) Adding 250, 380 and 570 mg·kg^-1 coated ZnO significantly increased duodenum villi height (P<0.05), and which had no significant differences with that of HZ (P>0.05); V/C values of duodenum, jejunum and ileum, compared with that of LZ, were greater (P<0.05)when feeding the diets adding 570 or 760 mg·kg^-1 coated ZnO. It is concluded that adding 380-570 mg·kg^-1 coated ZnO, as pharmacological concentrations of ZnO does, can protect intestinal morphology and decrease diarrhea effectively, moreover,can save Zn source and reduce environmental pollution.