Abstract: This study was conducted to assess the effects of dietary supplementation with 5 different rates of probiotic fermentation feed prepared with Kinggrass No.1 on production performance and feeding economic benefit of black pig. A total of 180 healthy binary hybrid black pigs with similar weight were selected and randomly divided into 6 groups with 3 replicates for each group and 10 individuals for each replicate. The control group was fed with the basal diet, and the experimental groups of Ⅰ, Ⅱ, Ⅲ, Ⅳ and Ⅴ were fed with the basal diet supplemented with 10%, 20%, 30%, 40% and 50% probiotic fermentation feed prepared with Kinggrass No.1, respectively. The feeding experiment was composed of a 7 days pre-test period and a 60 days formal test period. The average daily gain, average daily feed intake, diarrhea rate, dressing percentage and feeding gross profit of different groups were calculated and compared. The results showed that, except for experimental group Ⅲ （P>0.05）, statistically significant （P<0.05） differences in average daily gain between the other 4 experimental groups and the control group were found; the highest average daily gain was observed in experimental group Ⅱ （865.24 g per pig）, followed by experimental group Ⅰ （839.33 g per pig）, increased by 23.24% and 19.55% respectively compared with control group; the lowest average daily gain was observed in experimental group Ⅴ （552.51 g per pig）, which was decreased by 21.31% compared with control group. The highest and lowest average daily feed intakes were observed in experimental group Ⅴ （3.35 kg per pig） and control group （2.30 kg per pig）, and there were statistically significant （P<0.05) differences in average daily feed intake between the 5 experimental groups and control group. In terms of dressing percentage, statistically significant （P<0.05） inter-group differences were observed among experimental groups Ⅲ, Ⅳ and Ⅴ, while no statistically significant （P>0.05） difference between experimental group Ⅰ and experimental group Ⅱ was found; with the increase of supplementation rate of probiotic fermentation feed prepared with Kinggrass No.1, the dressing percentage of the black pigs exhibited a deceasing trend; the control group and experimental group Ⅴ had the highest and lowest dressing percentage, respectively. The highest feeding gross profit was obtained in experimental group Ⅱ （21 259.0 Yuan）, and the lowest feeding gross profit was obtained in experimental group Ⅴ （10 325.7 Yuan）. In summary, 20% dietary supplementation of probiotic fermentation feed prepared with Kinggrass No.1 has the best performance in improving production performance of fattening black pig and obtains the best feeding economic benefit.

Key words: Kinggrass No.1, black pig, fattening, economic benefit