Efficacy of a herbal product against Histomonas meleagridis after experimental infection of turkey poults.

Histomoniasis (infectious enterohepatitis, blackhead) is caused by the protozoan parasite Histomonas meleagridis (H. meleagridis). After the ban of all prophylactic and therapeutic drugs in the European Union, histomoniasis is increasingly responsible for considerable economic problems to the poultry industry. The aim of this study was to investigate the effect of a herbal product with extracts from cinnamon, garlic, lemon, and rosemary on H. meleagridis in turkey poults in vivo. For this purpose, 60 two-week-old poults were divided into three groups. Group 1 received the herbal product in the feed six days before infection and in water three days before infection, then in feed and drinking water until the end of the experiment. Groups 2 and 3 were left untreated. At week 3 of age, Groups 1 and 2 were infected intracloacally with H. meleagridis. Three weeks after infection the surviving birds were euthanized and examined for pathological lesions. Mortality was 20% in Group 1 and 50% in Group 2. There were no deaths in Group 3. DNA of histomonads was detected in all examined caeca and livers of the dead birds, but was not detected in any examined organ of the surviving birds of all groups. There was no noticeable difference in the lesion scores of the dead birds between the groups. The surviving birds of all groups did not show lesions post mortem. Since all effective prophylactic and therapeutic drugs against histomoniasis were banned in the EU, under given conditions the investigated herbal product seems to be an effective alternative for the reduction of mortality in turkeys caused by histomoniasis.