Authors

Discussion

Coccidiosis disease is recognised as one of the main causes of economical losses in the poultry industry. The treatment is mainly based on the use of anticoccidial drugs, however the presence of drug-resistant strains of Eimeria parasites and the growing public concerns about drug residues in food, have stimulated the interest in finding more natural alternative compounds as a source of treatment. Therefore, we explored in this study the anti-parasitic effect of Garlic, Oregano, Thyme and Sage essential oils on Eimeria tenella in vitro. The study evaluated the effects in the infection of E. tenella sporozoites in Madin-Darby bovine kidney (MDBK) cells. The intracellular invasion of pre-treated parasites was quantified by detection of E. tenella DNA using qPCR from cell monolayers collected at 2 and 24 hours post-infection. Essential oils were tested at different concentrations (100, 50, 20, 5 μg/ml), and compared either with the oil solvent (DMSO) or the anticoccidial drug Robenidine. Results show that parasite invasion and replication was not influenced when pre-treated with low doses of any essential oils. In opposition, a significant reduction of intracellular sporozoites was found using high doses of Oregano and Garlic essential oils. Parasite invasion was reduced by 93% after 24 hours of exposition to 100 ug/ml oregano oil, while Garlic essential oil reached a maximum inhibition of 70% using 50 μg/ml concentration. A profile of inhibition was also observed using Thyme and Sage oils, however the inhibition did not achieve statistic significant due to a higher variability. Garlic and Oregano oils have also been tested in vivo confirming their potential as biocomponents to prevent coccidiosis disease. These promising results will be further explored by evaluating combinations of the optimal inhibitory doses of the different essential oils.

Key words: Essential Oils, E. tenella, inhibition