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ARS Home » Research » Publications at this Location » Publication #83199


item Danforth, Harry
item JAYNES, J

Submitted to: Parasitology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Avian coccidiosis, an intestinal disease of poultry caused by an intracellular protozoan parasite, costs the poultry industry over $350 million annually. This disease has been partially controlled by use of anticoccidial compounds fed to chickens and turkeys in the feed. However, use of this control method has diminished in efficacy over the last 10 years because of increased drug resistance by the parasite to anticoccidials. Thus, there is a continuing search for new anticoccidial compounds to control this disease. In this study, the effect of a synthetic derivative of a natural compound that originally was produced by insects for protection against bacteria was evaluated against the coccidial parasites. Seven different types of these compounds, known as lytic peptides (trade name Peptidyl-MIMs) were found to destroy the coccidial parasites within minutes of peptide exposure. Electron microscopy showed that the peptides produced openings in the parasite membrane that caused their lysis. Treatment of chickens with these peptides during the coccidial infection showed a reduction in intestinal lesions caused by the parasites. The results showed that these compounds could be quite effective in controlling avian coccidiosis.

Technical Abstract: A study of the lytic effect of 7 different Peptidyl-MIMs (pMIMs) on sporozoites of 5 different species of Eimeria infecting chickens and merozoites of 2 different species that infect chickens showed that all of the pMIMs were effective at concentrations of 1 to 50 uM against the parasites for incubation periods varying from 1 to 20 minutes. In addition, electron microscopy showed that ultrastructural degeneration of the pellicle of sporozoite stages of the parasites occurred within 5 to 10 minutes after exposure to 5 uM concentration of 3 different pMIMs. Pore- like openings were seen in the pellicle of the sporozoites at the ultrastructural level which indicated that the pMIMs had the same mechanism of action on the parasites as that reported for studies done on bacteria. A reduction in lesion scores was seen in chickens treated with 10, 50 or 75 uM concentrations of 2 different proteolytic stabilized pMIMs after challenge with 3 different species of avian coccidia in battery cage trials. Collectively these data indicated that pMIMs may be useful in the control of coccidiosis in poultry.