(See pictures of the world's largest trout in the wild.)

Developed with fish farming in mind, the genetically modified trout is the result of ten years of experimentation by a team led by Terry Bradley of the University of Rhode Island's Department of Fisheries, Animal, and Veterinary Sciences.

The team injected 20,000 rainbow trout eggs with different types of DNA from other species, making them transgenic. The added DNA was intended to suppress a protein called myostatin, and it apparently worked in about 300 of the eggs, turning them into the muscle-bound superfish.

The transgenic trout incorporate genes modeled on myostatin-inhibiting proteins found in powerfully built Belgian blue cattle, a beef breed noted for its "double muscled" appearance.

In mammals, including humans,