Abstract: With the advent of the era of feed without antibiotics, the research and development of feed without antibiotics or alternative antibiotics has become a hot spot of current research. Earthworms are high–quality protein feed, and Chinese medicine believes that earthworms have a number of therapeutic effects. The aim of this study was to determine the antibacterial activity of earthworm homogenate on Escherichia coli, Staphylococcus aureus, Streptococcus and Haemophilus parasuis from pig farm, with the antibacterial activity of earthworm homogenate treatment solution studied by Kirby-Bauer test（K-B）and ultraviolet spectrophotometry. The study showed that the supernatant of the earthworm homogenate had antibacterial effects on Escherichia coli, Staphylococcus aureus, Streptococcus and Haemophilus parasuis. The highest concentration of earthworm homogenate supernatant with a ratio of earthworm to water of 2:1 has antibacterial activity on Escherichia coli. The supernatant of earthworm homogenate had obvious and broad–spectrum antibacterial activity effect on Staphylococcus aureus. The ratio of earthworm to water 4:5 had obvious antibacterial activity on Streptococcus and Haemophilus parasuis. The spectrophotometric test showed that two different concentrations of supernatant of earthworm homogenate had different degrees of bacteriostatic effect on Escherichia coli, Staphylococcus aureus and Streptococcus. Earthworm homogenate 2 was more effective. 24 hours later, the antibacterial advantage of earthworm homogenate supernatant disappeared completely. This study showed that the supernatant of earthworm homogenate has certain bacteriostasis to common harmful bacteria in pig farm, which can provide theoretical basis for the development of new feedstuffs related to earthworms.

Key words: Earthworm, homogenate supernatant, Kirby–Bauer test（K-B）, ultraviolet spectrophotometry, antibacterial