Effect Of Different Surface Area Micronized Zinc Oxide On Growth Performance,Tissue Zinc Content,and Intestinal Health Of Meat Ducks

This study was conducted to investigate the effect of different surface area micronized zinc oxide on growth performance,nutrient utilization,tissue zinc content,intestinal health,and antioxidant capacity of meat ducks.A total of 480 one-d-old cherry valley ducks were randomly divided into 4 dietary treatments with 12replicates and 10 ducks per replicate.The experiment lasted for 35 days.Dietary treatments included a basal corn-soybean meal diet supplemented with the ZnSO4(control group),common micronized ZnO(C-ZnO,surface area:11.30 m~2/g),active micronized ZnO(A-ZnO,surface area:20.90 m~2/g)and porous micronized ZnO(P-ZnO,surface area:34.02m~2/g).The amount of dietary zinc was 120mg/kg of diet for the whole experiment period.The results showed as follows.1)Body weight(BW,35 d),body weight gain(BWG,14-35 d and 1-35 d)of ducks in A-ZnO group significantly increased,while feed to gain ratio(F/G,14-35d and 1-35d)and the utilization of ether extract(EE)significantly decreased when compared to the other three groups.2)Compared with control group(ZnSO4),the hepatic Zn content in three micronized ZnO groups were significantly increased(P<0.05),the Zn content in pancreas of three ZnO groups tended to increase(P=0.051).Serum Zn content in P-ZnO group was significantly higher than that in A-ZnO group.The content of metallothionein(MT)in liver showed no difference(P>0.05)in each treatment groups,but the mRNA expression of MT in C-ZnO and P-ZnO groups were significantly increased when compared to the control group.3)At 14 d of age,the villus height of jejunum in C-ZnO group significantly increased as compared to control group and P-ZnO group(P<0.05).The crypt depth of jejunum in three micronized ZnO groups significantly decreased(P<0.05),while the ratio of villus height to crypt depth(V/C)in C-ZnO and A-ZnO groups significantly increased when compared to control group.At 35 d of age,the villus height and V/C of jejunum in C-ZnO group and P-ZnO groups significantly increased(P<0.05)compared to control group.However,the crypt depth of jejunum in A-ZnO group significantly increased when compared with other three groups(P<0.05).4)Compared with the control group,the content of hepatic MDA in C-ZnO and P-ZnO groups significantly decreased(P<0.05),and the activity of jejunal SOD in C-ZnO and A-ZnO groups significantly increased(P<0.05);the activities of serum T-AOC(P=0.088)and hepatic SOD(P=0.060)in three ZnO groups had a tendency to increase.5)When compared to the control group,the mRNA of OCLN,ZO-1 and ZO-3genes in P-ZnO group significantly decreased(P<0.05)31.44%,36.03%and 24.43%,respectively,while the mRNA of ZO-3 in A-ZnO and C-ZnO groups significantly increased(P<0.05)25.47%and 55.96%,respectively,and these genes expression in A-ZnO group were higher(P<0.05)than these in C-ZnO group;The mRNA of MUC2in C-ZnO,A-ZnO and P-ZnO groups significantly increased(P<0.05)137.93%,291.82%,109.99%,respectively,what’s more,A-ZnO group showed higher level;The mRNA of sIgA in A-ZnO and the mRNA of LYZ in P-ZnO group significantly increased(P<0.05)34.76%and 61.05%,respectively.These results suggested that the supplementation of A-ZnO in diet contributed to growth performance in ducks via increasing of antioxidant capacity and improving intestinal physical barrier and chemical barrier function.