New method improves vaccines for fish farms

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Capital News Service
LANSING — Forget about the debate over vaccinating kids. There’s no debate that vaccinating fish can allow the aquaculture industry to grow.
A recent study in the Journal of Vaccine shows that a new technique makes it possible to give fish two vaccines at a time. That’s important because it could save time and money for fish farmers trying to expand the industry.
A traditional method is to vaccinate fish by injection. But mixing more than one vaccine in the same injection can inhibit their effectiveness.

The new method delivers vaccine by dropping it into the nostrils of the fish. One vaccine is delivered into one nostril and a second vaccine into the other. The method delivers both vaccines in a single operation without limiting their effectiveness.
Use of vaccines in the aquaculture industry is analogous to what happens in the livestock industry.
On fish farms, fish are kept at high densities, allowing disease to spread extremely easily, said Carolyn Schulz, an assistant professor of fisheries and wildlife at Michigan State University and former research assistant in the fish health lab used by the Department of Natural Resources.
Fish farmers often use surface water from a lake or river in their tanks, and it’s not uncommon for that water to contain bacteria or parasites, Schulz said.
To kill bacteria, a fish farmer may use ultraviolet light – but that doesn’t always work.
Other methods for keeping out diseases include separating the tools used for different tanks, sterilization and antibiotics, said Ron Kinnunen, an Extension educator focusing on aquaculture for Michigan Sea Grant.
Vaccinations serve like an insurance policy, said Roy Yanong, a professor and researcher in the Tropical Aquaculture Laboratory at the University of Florida.
That’s important because the industry could be a hidden gem of Michigan’s economy, said Jerome Kahn, the owner and operator of Cedarbrook Trout Farm in Harrisville, Alcona County.
Aquaculture is a $4 million to $5 million industry in Michigan, but with proper management and regulation it could reach closer to $50 million, Kahn said.
Fish disease and parasites are major threats to the industry. Eliminating them is one of nine goals set by the National Strategic Plan for Federal Aquaculture Research to help the industry grow.
For fish farms, vaccines are a proven way to battle disease.
The vaccine study looked at rainbow trout, a species that Kahn recently added to his business. That addition created a 100 percent growth in sales with only a 25 percent increased production cost, he said, adding that it shows how aquaculture has great economic opportunity.
In the Great Lakes states, there aren’t nearly as many fish diseases as elsewhere in the United States, said Sea Grant’s Kinnunen. However, some of the diseases present are harmful ones.
The most recent example is a strain of Viral Hemorrhagic Septicemia – VHS – which causes fish to bleed and eventually leads to their death, according to the Minnesota Department of Natural Resources.
There is no vaccine for VHS, but the U.S. Department of Agriculture has been trying to develop one since 2010.
Without such a vaccine, all fish coming from Michigan fish farms must be certified free of VHS and other diseases, Kinnunen said.
Eamon Devlin writes for Great Lakes Echo
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