Abstract: This study was designed to assess the effect of yeast culture(YC)on productive performance of boar.A total of 90 boars weighing approximately 80 kg were randomly assigned to one of three groups(n=30)such that control group was fed with the basal diet,experimentalⅠgroup(n=30)and experimentalⅡgroup(n=30)were fed with the basal diet supplemented with 5 kg/t and 7 kg/t of yeast culture,respectively.The period of the pre-experiment and formal-experiment lasted for 5 d and 45 d,respectively.During the whole experiment process,the boars of the three groups were reared under the same feeding and management condition.At the end of the experiment,the semen color and flavor of the boars from different groups were evaluated;the semen volume and pH value as well as the sperm motility,density,abnormal rate and resistance index of the boars from different groups were also determined and statistically compared.The results showed that no obvious differences in semen color and flavor between the boars from experimentalⅠgroup and experimentalⅡgroup were observed;the three groups had the same sperm resistance index;the experimentalⅠgroup and experimentalⅡgroup had significantly higher semen volume,sperm motility and sperm density as well as significantly lower sperm abnormal rate compared to the control group(P<0.05),but no significant differences in the above four indexes between experimentalⅠgroup and experimentalⅡgroup were found(P>0.05);there was no statistical difference in semen pH value between the three groups(P>0.05).These results indicate that dietary supplementation of yeast culture can improve the productive performance of boar.