Evaluation of Lethal Effect of Aqueous and Alcoholic Extracts of Glycyrrhiza glabra on the Emeria tenella Oocysts In Vitro

Coccidiosis is one of the most common infectious diseases in poultry that causes huge economic losses. Glycyrrhiza glabra is a medicinal plant that used traditionally. The aim of the present study was to evaluate the effect of aqueous and alcoholic extracts of this plant on the Emeria tenella oocysts in vitro.

The unsporulated oocysts were obtained by inoculation of 14th day-old broiler chicks with 75,000 oocysts. To obtain sporulated oocysts, 9g of feces samples was soaked in 2% potassium bichromate and incubated at 27°C for 72h. Aqueous and alcoholic extracts of Glycyrrhiza glabra in concentrations of 1, 2, and 5% were prepared and oocysts were exposed to these extracts for 48 hours. Thereafter, the number of sporulated and unsporulated oocysts were counted at 1, 12, 24, and 48 hours. In order to prevent any error, the experiments were repeated three times.

Both extracts of Glycyrrhiza glabra in all tested concentrations cause a significant reduction in the number of sporulated and unsporulated Eimeria tenella oocysts compared with control (p<0.05). The rate of inhibitory effect of extracts had a direct relationship with exposure time, and inhibition was continuously increased over time.

Alcoholic extracts of Glycyrrhiza glabra had a better effect than aqueous extracts. 5% alcoholic extract had the best effect. However, further studies are needed to find the best dose for the most anticoccidial effects and also to show its effects on other species of Eimeria and in animal models.