Abstract: This study explored the effect of different proportions of zinc amino acid chelates(Zn-AAC) and zinc sulphate(ZnSO4) on the growth performance of weaning pigs. Forty five hybrid pigs of 28 days old were selected and randomly allotted to one of five dietary treatments. There were three replicates per treatment and three pigs in each replicate. All animals were fed with the same basic diet supplied 100 mg/kg of zinc but with different proportions of organic zinc (Zn-AAC) and inorganic zinc (ZnSO4). Pigs in the control group were complemented with 100% ZnSO4， and the amount of zinc in diets of group 2， 3， 4 and 5 were substituted with 40%，60%，80% and 100% Zn-AAC，respectively.The 28-day trial included two phases of 1 to 14 d and 15 to 28 d.Data obtained in this study showed: from day 1 to day 14， the ADG of piglets in group 2，3，4 and 5 was increased by 22.0% (P>0.05)， 38.5% (P<0.01)， 32.6% (P<0.05) and 26.2% (P<0.05)， respectively， and ADFI， by 24.6% (P<0.05)， 25.3% (P<0.05)， 23.5% (P<0.05) and 23.8% (P<0.05)， respectively， when compared with the control piglets. From 15 to 28 d， all animals fed with organic zinc displayed higher ADFI than the control group (P>0.05). From 1 to 28 d， piglets fed diets with 60% of organic zinc had statistical improvement in ADG(P<0.01)， with no significant change in FCR. In conclusion， the supplementation of organic zinc with normal dosage could increase the ADG， ADFI. The combination of organic and inorganic zinc is superior to either one. The optimal proportion of organic zinc to inorganic zinc is 60∶40.

Key words: zinc; growth performance; weaning pigs