Experiment tests effects of creatine on fish

Anglers like fish that fight. Aquaculture businesses want fish that are stronger.

Researchers at MU are trying to determine whether creatine supplements can enhance stamina and growth in fish, possibly improving sport fishing and open-ocean aquaculture.

MU fisheries professor Rob Hayward said feeding creatine to fish could benefit those who operate fee-fishing businesses by making their fish better fighters. “If I can get one on the line and it fights for 10 to 15 minutes, that is a memorable fishing experience,” Hayward said.

Aquaculture also stands to benefit. Those operations are now primarily found inland or near the shore, Hayward said, but they will soon be moved as far as 200 miles offshore. Fish with more stamina would better handle ocean currents.

“There haven’t been too many opportunities to grow fish in open ocean water,” said Kyle Winders, an MU fisheries and wildlife student involved in the research. “It would be a great chance to raise more fish.”

The researchers are also interested in whether creatine can speed up muscle growth.

“Fisheries industries would definitely benefit because it would produce leaner, stronger fish,” said Amber Wiewel, another fisheries and wildlife student involved with the project.

Marvin Emerson, president of Crystal Lake Fisheries in Ava, produces rainbow trout as recreational fish. He sees both sides of using creatine supplements — a stronger fish could enhance his business, but public perception and acceptance of using creatine supplements could be a barrier.

“I think we would be foolish not to consider it,” Emerson said. “You have to weigh the variables, though.”

Curtis Harrison, who raises game fish at Harrison Fish Farm in Hurdland, believes the creatine supplement could affect producers’ bottom lines.

“They’re going to get a bigger fish, faster and for less money,” he said.

Creatine that is ingested binds to high-energy phosphate in the muscle. Creatine phosphate, found naturally in living things, is an amino acid chain that provides energy for muscle contraction. When a person exercises, creatine phosphate levels decrease, leading to fatigue. Creatine supplements can provide an additional source of energy. Earlier research at MU focused on using creatine to make pork juicier.

To test the stamina and muscle growth in bluegill, brown trout and rainbow trout, researchers used a 5-foot, double-wall Plexiglas tube. The tested fish were placed in the inner tube. Water in the apparatus was pushed through the inner tube, creating a current. The fish are oriented nose-first into the current. Current can be increased or decreased to test whether or not the creatine consumed by fish allows them to swim longer with stronger current. Think of it as a treadmill for fish.

“It’s like they had a real heavy workout,” Hayward said.

In the experiment, 20 fish were used. Ten in the control group had an unaltered diet. The 10 in the treatment group were fed a 5 percent creatine diet.

Hayward described the results as “not conclusive but interesting.” Only the rainbow trout showed a favorable response to the supplement. Fish that didn’t consume creatine had an average swim time of 9.7 minutes. In the group that had the 5 percent creatine diet, two fish showed remarkable endurance: one swam for 120 minutes, and another swam for 127 minutes. The other eight didn’t show much response.

Hayward said the difference in response is similar to what humans who use creatine see.

“In the gym, you will see people using creatine, and you will see differences in how people respond,” Hayward said. “Some fish may be predisposed to respond to the creatine.”

Hayward thinks the results have meaning because if the two fish that swam significantly longer had been random, he would have expected similar results in the control group.

The next step in the research will be a tissue analysis to see whether the fish that swam longer have more creatine in their muscle.

No federal agency has approved human consumption of fish that are fed creatine.

“We’re just doing the science,” Hayward said. “If it is really something, there will be a lot of inertia to get it approved.”