Garlic wards off vampire-like parasites

By Wes Judd 11 September 2013
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Garlic can help fish avoid fanged, vampire-like parasites, a new study has found.

IT MIGHT SOUND LIKE a myth, but new research has revealed garlic has the ability to ward off fanged, vampire-like parasites in fish.

A PhD candidate from James Cook University in Queensland has discovered farmed fish fed a garlic-enriched diet were less susceptible to the monogean flat-worm parasite Noebenedenia than fish that didn’t consume garlic. The parasite has recently plagued fish farmers.

But Thane Militz, the lead researcher, didn’t realise the mythical implications of his work until he presented it to a room of undergraduates.

At the end, one brought up the vampire link.

“That was really the first time I noticed the irony, to be honest; it hadn’t really crossed my mind before then,” says Thane.

Truth behind the vampire/garlic myth

Although satirical, his recent discovery, published in Aquaculture, carries a lot more significance than a simple cultural coincidence.

Over the course of a year, Thane was able to show that after consuming a garlic enriched diet, farm produced barramundi were 50% less susceptible to the harmful Neobenedenia. “This parasite is very unique. It’s one of the few types that infect a vast diversity of hosts —pretty much all bony fish,” says Thane.

His work was inspired by the fact that garlic has previously shown to greatly improve the immune system of various fish. Thane thought the appropriate next step was to see if it had any positive medical affects against worm parasites.
For a month, he fed the fish a garlic enhanced diet of varying amounts, with a control group of normally fed barramundi.

Relief for fish farmers

“Amazingly, after 30 days, half the barramundi given the garlic feed were completely free of infection whilst 100% of barramundi fed an un-enriched diet became infected and with substantially more parasites,” he says. He also noted that the month long duration was particularly important, as there was no sign of decreased parasitic activity until after 30 days.

After struggling with fish that seemed to lack an appetite in his own parasitic experiments, Dominique Roche of the Australian National University thinks this discovery is one of particular note. “It’s extremely good for aquaculture. It’s always more preferable to use a natural treatment [against parasites], but it also stimulates their appetite. It’s a double whammy!”

Natural way to ward off parasites

Although he doesn’t know exactly why garlic has this effect—“it’s possible the parasites simply don’t like the taste of garlic fed fish, or the fish’s enhanced immune system drives them away”—no one is complaining.

The alternative anti-parasitic agent consists of harsh chemicals that are neither great for the fish nor its environment. Not to mention the fish don’t enjoy the taste.
“Garlic offers an entirely natural, low cost solution to managing parasites, [and] poses no danger to work operatives, the fish, or the environment. Additionally, the fish seemed to love it! It’s a win-win situation for everyone,” he says.

Thane insists that this is hopefully just the first step in a long line of natural methods for disease control.


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