Abstract: The study was conducted to investigate the effects of replacing antibiotics using different dosages of organics acidifier on growth performance of weaning piglets. A total of 144 Duroc×Landrace×Yorkshire crossbred weaning piglets with similar initial average body weight [（8.70±0.20）kg] and days of age were randomly divided into 4 groups, including control group and experimental groups of 1, 2 and 3. There were 4 repeats in each group and 9 piglets in each repeat. The control group was fed with basal diet,the experimental group 1 fed the basal diet supplemented with 25 mg/kg duomycin and 50 mg/kg quinocetone, and the experimental groups of 2 and 3 received dietary supplementation of 0.4% and 0.7% organic acidifier composed of formic acid, lactic acid, citric acid and fumaric acid, respectively. The experimental period lasted for 14 days. The results showed that compared to the control group, the daily gain of the experimental groups of 1, 2 and 3 were significantly （P<0.05） elevated by 20.60%, 7.90% and 15.30%, respectively; the feed to gain ratio of the experimental groups of 1, 2 and 3 were significantly （P<0.05） reduced by 13.20%, 7.60% and 13.35%, respectively;the diarrhea rate of the experimental groups of 1, 2 and 3 were 16.11%, 11.11% and 15.91% lower than that of the control group, and significant （P<0.05） differences were observed; there were no significant （P>0.05） difference in average daily feed intake between the control group and the three experimental groups; the experimental group 3 had the similar effect on improving daily gain and feed to gain ratio of the weaning piglets with experimental group 1. In conclusion, dietary supplementation of organic acidifier improved the growth performance of weaning piglets, and the higher dosage of organic acidifier had the similar effect with the combinative use of duomycin and quinocetone.

Key words: organic acidifier, growth performance, diarrhea rate, weaning piglet