Effects of montmorillonite–zinc oxide hybrid on performance, diarrhea, intestinal permeability and morphology of weanling pigs

Abstract

Effects of montmorillonite–zinc oxide hybrid (MMT–ZnO) on performance, diarrhea, intestinal permeability and morphology were investigated. A total of 180 piglets (Duroc×Landrace×Yorkshire, average initial weight of 7.2±0.3kg weaned at 27±1d age) were randomly allotted to five groups for two weeks, each of which has six pens with six pigs per pen. The dietary treatments were: (1) basal control diet, 100mg/kg of supplemental Zn as ZnSO4; (2) basal diet+2.0g/kg montmorillonite (MMT), equivalent to the MMT in the MMT–ZnO treatment; (3) basal diet+500mg/kg of Zn as ZnO; (4) basal diet+500mg/kg of Zn as MMT–ZnO; (5) basal diet+2000mg/kg of Zn as ZnO. The results showed that supplemental 500mg/kg of Zn from MMT–ZnO or 2000mg/kg of Zn from ZnO improved (P<0.05) average daily gain and daily feed intake, decreased (P<0.05) fecal scores at 7 and 14d postweaning, reduced (P<0.05) plasma d-lactate and diamine oxidase activity, improved (P<0.05) villus height and the villus height:crypt depth ratio at the jejunal mucosa as compared with the control, MMT or 500mg/kg of Zn from ZnO. Pigs fed with 500mg/kg of Zn as MMT–ZnO had lower (P<0.05) plasma levels of d-lactate than those fed with 2000mg/kg of Zn as ZnO. Pigs fed with 500mg/kg of Zn as MMT–ZnO had lower (P<0.05) number of intestinal Clostridium and Escherichia coli than those fed with the control, MMT or 500mg/kg of Zn as ZnO. Supplementation with 2000mg/kg of Zn as ZnO reduced (P<0.05) the number of Clostridium in proximal colon as compared with the control while had no (P>0.05) influence on intestinal E. coli. Supplemental MMT or 500mg/kg of Zn from ZnO had no (P>0.05) effect on growth performance, intestinal microflora, permeability and morphology as compared to the control group. The results indicated that dietary addition of 500mg/kg of Zn from MMT–ZnO was comparable to 2000mg/kg of Zn from ZnO while more effective than MMT or 500mg/kg of Zn from ZnO for enhancing growth performance, alleviating diarrhea, as well as improving intestinal microflora, mucosal barrier integrity and morphology of weaned pigs.