Abstract: Trichomonas gallinae is one kinds of highly transmissible parasitic disease, which seriously affects the production performance of pigeons, even leading to the death of pigeons. These bring huge economic losses to the pigeon industry. However, in clinical practice, the therapeutic drugs that used to prevent and control of Trichomonas gallinae are mostly chemical drugs, the use cycle of these chemical drug is short and the side effects are large. In order to develop the natural anti-parasitic drugs in clinic, this paper studied the clinical efficacy of Gentiana scabra against Trichomonas gallinae, providing the new medication strategy for the treatment of Trichomonas gallinae in the pigeon industry. By isolating, identifying, and purifying of Trichomonas gallinae, the stable strains were obtained for subsequent experiments. The relative growth inhibition rate and minimum effective concentration of Gentian water extract against Trichomonas pigeon were determined in vitro. In order to further observe the efficacy, different doses and concentrations of Gentian water extract were added to the basic diet, and the effects of Gentian water extract on body weight, survival rate, activity of Trichomonas pigeon, blood biochemical indexes and contents of inflammatory factors were measured in vivo, so as to evaluate the clinical efficacy of Chinese herbal medicine Gentian against Trichomonas pigeon in vivo and in vitro. The results of in vitro test showed that the minimum effective concentration (MEC) of Gentian water extract was 50 mg·mL^-1, which showed strong anti-Trichomonas pigeon activity in vitro. The results of in vivo experiments showed that the water extract of Gentian herb had the effect of restoring the body weight and improving the survival rate of the sick pigeons. The insecticidal effect of Gentian water extract was significant compared with control group (P<0.05), but had no significant difference compared with metronidazole group (P>0.05), and the duration of efficacy of Gentian 500 mg·mL^-1 per group was longer than that of metronidazole group; The contents of alanine aminotransferase (ALT), AST and ALT/AST in serum were lower than those in control group. Serum levels of three inflammatory factors, interleukin-6 (IL-6), interleukin-1β (IL-1β) and transforming growth factor-β (TGF-β), were higher than those in the control group, similar to metronidazole group. Gentian water extract has significant clinical efficacy in the treatment of Trichomoniasis of pigeon, and its efficacy reaches the therapeutic effect of metronidazole, and has no significant toxic side effects. Therefore, Gentian can be used as a potential natural drug development against trichomoniasis of pigeon.

Key words: Chinese medicine Gentian, Trichomonas pigeon, metronidazole, clinical efficacy research