Trout Replace Mice in Cancer Studies : Rainbows Cheaper to Raise, Provide Diversity to Confirm Results

Rainbow trout, long sought by sportsmen for their fighting qualities, have been enlisted by scientists in the battle against cancer.

Researchers at Oregon State University who are studying links between food and cancer have turned to trout as an alternative to rats and mice for laboratory experiments.

“Rainbow trout have advantages over rats and mice,” said Dr. George Bailey, a biochemist in Oregon State’s food science department. “One is a very simple budget matter. They are more cheaply raised.”

Check Results

Trout also provide an alternative model for experiments, he said.

“If we work only with rats, how do we relate it to the human situation? But if we reach out to other vertebrate species, if we find processes that affect both rodents and fish, then we can be pretty sure the same thing will apply to man,” Bailey said.

A team of scientists led by Bailey recently won a $1.8-million grant from the National Institute of Environmental Health Sciences to expand cancer studies using trout.

Bailey and five other scientists are conducting a three-pronged investigation of the relationship of diet to cancer, studying food compounds that might be cancer-causing, food elements that might promote the growth of cancer cells, and foods that may block or slow cancer.

Lower Costs

It costs about $6 to $8 a year to raise a trout for research, compared to between $100 and $150 for a white rat in a laboratory, Bailey said.

Trout can be raised by the thousands in tanks while rats require a building and a lab technician to feed them and clean their cages.

“Research that might cost $10,000 to $15,000 in trout might cost $900,000 to $1 million with rats,” Bailey said.

The lower cost of trout allows researchers to use much larger numbers of test animals, increasing the accuracy and sensitivity of tests.

Bailey said trout react the same way as rats to many carcinogens. The fish are also physiologically better in one way. Like humans, they have a gall bladder, while rats do not.

“Bile excretions from the gall bladder are a major way cancer (-causing) materials are excreted from the body,” Bailey said.

Oregon State has pioneered the use of trout for research over the last 20 years. The program grew out of animal husbandry research to find better food for fish hatcheries.

Hatchery Food Developed

Liver cancer plagued many trout hatcheries in the Northwest, and the program determined that an agent in meal used in hatchery feed was responsible for the disease.

The research led to development of the Oregon Trout Pellet, which is now the standard hatchery trout food used across the nation.

The research left the school with its own hatchery and a vast amount of data about trout diet that gave the cancer researchers a head start.