Comparative Effect of Allicin and Alcoholic Garlic Extract on the Morphology and Infectivity of Eimeria tenella Oocysts in Chickens

SIMPLE SUMMARY: Avian coccidiosis is one of the major diseases threatening the poultry industry in Egypt and worldwide. As such, developing a new oocysticidal to control this disease seems crucial. The present study examined the in vitro effects of allicin and alcoholic garlic extract at different concentrations as natural disinfectant candidates compared with KOH 5% as a chemical disinfectant against Eimeria tenella oocysts and the in vivo infectivity of these treated oocysts in chickens. The morphological changes in the treated oocysts were examined using light microscopy and scanning electron microscopy. The in vivo infectivity was evaluated using a gross and histopathological examination of the cecal tissues to determine the most significant changes. The study showed promising results for using Allicin at a concentration of 180 mg/mL and garlic at a concentration of 360 mg/mL in reducing the number of oocysts, the sporulation percentage, and the number of oocysts with marked deformities. The sporulated oocysts exposed to Allicin and alcoholic garlic extract revealed the lowest infectivity and pathogenicity, resulting in a minor gross lesions score. In addition, restoration of the major reported histopathological changes compared to oocysts sporulated in media containing the KOH 5%. Collectively, this study provides novel information regarding the potential use of natural extracts of allicin and alcoholic garlic as environmentally eco-friendly disinfectants in poultry farms to reduce the spread of coccidiosis. ABSTRACT: Avian coccidiosis remains one of the major parasitic diseases that threaten the global poultry industry. Since prevention is superior to treatment, this study focuses on eliminating the infection outside the host. To determine their effect on the viability of Eimeria tenella oocysts in vitro, allicin and alcoholic garlic extract, which are natural, less toxic, and inexpensive products, were compared to KOH 5% (chemical disinfectant) using an in vitro culture system. Three concentrations of allicin (45, 90, and 180 mg/mL) and alcoholic garlic extract (90, 180, and 360 mg/mL, were used. Subsequently, destructive and sporulation-inhibiting effects on Eimeria oocysts were detected using light and electron microscopy. Young chickens were infected with treated sporulated oocysts to determine their effect on infectivity. After 7 days pi, the percentage of excreted oocysts (oocyst shedding) was determined, and the chickens were slaughtered for histopathological examination of the cecal tissues. Under an electron microscope, allicin at a concentration of 180 mg/mL and alcoholic garlic extract at a concentration of 360 mg/mL demonstrate a high oocysticidal activity with severe destruction of the oocyst wall and the appearance of pores. In addition, both concentrations directly affected the infectivity of sporulated oocysts by reducing the shedding of oocysts and the pathological lesions of infected young chickens. We concluded that the ability of Allicin and alcoholic garlic extract to eliminate Eimeria oocysts makes them superior to chemical disinfectants as a disinfectant.