Effects Of Nano Zinc Oxide On Growth Performance,Serum Biochemical Indices And Microbial Number In Colon Of Weaned Piglets

The experiment was conducted to investigate the effects of zinc oxide and nano zinc oxide on growth performance,serum biochemical indices,intestinal permeability and microbial number in colon of weaned pigs.A total of 280(Duroc×Landrace×Yorkshire)piglets,weaned at 24 d,were randomly assigned to 5 treatments,with 4 replicates per treatment and 14 pigs per replicate.Five dietary treatments were arranged in a single factorial arrangement randomLy.Groups consisted of a control group fed basal diets without zinc oxide,a high ZnO group fed diet with 3000mg/kg ZnO,and three treatments in which nano zinc oxide was added by 500mg/kg,1000mg/kg and 1500mg/kg,respectively.The experiment lasted for 14 days.At the end of experiment,one pig per replicate was selected to collect serum used to indicators of biochemical andintestinal permeability,and killed to collect colonic content used to determined number of E.coli.and Lactobacillus.The results were listed as follow:1.Growth performance: the ADFI,ADG,F/G and diarrhea index of the group with zinc oxide and groups with different levels nano zinc oxide were better than the control group(P<0.05).The ADFI of the group with 1500mg/kg nano zinc oxide was higher than that of the zinc oxide group(P<0.05),the group with 1500mg/kg nano zinc oxide was higher than that of the zinc oxide group(P>0.05),but there was no difference between them(P>0.05);and the ADFI of the zinc oxide group was higher than that of the group with 500mg/kg nano zinc oxide,but there were no difference between them(P>0.05).The ADG and F/G of the zinc oxide group and the groups with1000mg/kg and 1500mg/kg nano zinc oxide were significent better than that of the group with 500mg/kg nano zinc oxide(P<0.05),but there were no difference among them(P>0.05).On the diarrhea index,the group with zinc oxide and the groups with 1000mg/kg and 1500mg/kg nano zinc oxide were lower than that of the group with 500mg/kg nano zinc oxide(P<0.05),but there were no difference among them(P>0.05).2.Serum biochemical indices: the concentration of ALT and SUN in the zinc oxide group and different levels nano zinc oxide groups were lower than that of the control group(P<0.05),but there were no difference among them(P>0.05).The concentration of GLU in the groups with 1000mg/kg and 1500mg/kg nano zinc oxide were higher than that of the zinc oxide group and control group(P<0.05),and there was no difference between the zinc oxide group and the control group(P>0.05).The nano zinc oxide and the zinc oxide had no effect on the concentration of TP(P>0.05).As the level of nano zinc oxide increased,the concentration of the serum zinc and the activity of the ALP were increased significantly(P<0.05),and lower than that of the zinc oxide group significantly(P<0.05).The concentration of the serum zinc and the activity of the ALP of all treatment groups were higher than the control group significantly(P<0.05).3.Intestinal permeability: compared with the control group,the concentration of the D-lactate and diamine oxidase of the zinc oxide group and the nano zinc oxide groups were lower than the control group significantly(P<0.05).And the concentration of diamine oxidase of the zinc oxide group was lower than the nano zinc oxide groups(P>0.05).As the level of nano zinc oxide increased,the concentration of the D-lactate and diamine oxidase reduced.4.Microbial number in colon: compared with the zinc oxide group and the nano zinc oxide groups by 500 mg/kg,1000 mg/kg,and 1500 mg/kg,the number of E.coli of the control group increased significantly(P<0.05),but there were no significant difference among the four treatment groups(P>0.05);the number of Lactobacilli in the colon of the weaned piglets of the control group was significantly higher than that of the zinc oxide group,500 mg/kg,1000 mg/kg,and 1500 mg/kg nano zinc oxide group(P<0.05).These results indicated that: 3000 mg/kg zinc oxide and 1000 mg/kg or 1500 mg/kg nano zinc oxide used in diets improved the the growth performance,serum biochemical indices,intestinal permeability,reduced the number of E.coli and Lactobacilli in colon of weaned piglets.The effects of 1000 mg/kg or 1500 mg/kg nano zinc oxide reached that of 3000 mg/kg zinc oxide.These suggests that low-dose nano zinc oxide(1000 mg/kg and 1500 mg/kg)had the potential to replace high-dose common zinc oxide(3000 mg/kg);in view of the added cost and output benefits,the recommended amount of nano zinc oxide in weaned piglet diets was 1000 mg/kg.