August 17, 2015

Project could give boost to marine aquaculture

by Tim Crosby

CARBONDALE, Ill. – When you pick up those swordfish or tuna steaks at the grocery store, chances are they were imported from another country, where the fish were caught or grown in a marine aquaculture operation. 

So where is all the American-grown marine aquaculture – that is, food that comes from the ocean? It’s a tiny industry at the moment, hung up by logistical challenges to some extent, but also hamstrung by regulatory roadblocks that make the risky business that much riskier. 

A researcher at Southern Illinois University Carbondale, however, is working on a project that she and her colleagues around the country hope will satisfy the strict regulations and lead to the first-ever approval of a pharmaceutical “tool” for marine aquaculture operators in the United States. 

Jesse Trushenski, associate professor of zoology at SIU, is working with fellow researchers at Virginia Tech University and government officials at the National Oceanic and Atmospheric Administration and the U.S. Fish and Wildlife Service Aquatic Animal Drug Approval Partnership Program to test a common fresh-water aquaculture antibiotic – Aquaflor – on two marine species. The work began this summer with “in life” testing at Virginia Tech, with analysis to follow next year. Trushenski and SIU are acting as clearinghouse of information and coordinator of the efforts, which are aimed at winning government approval. 

As in any livestock operations, be it cattle or catfish, animals sometimes get sick. The problem with marine aquaculture in particular, however, is that there currently are zero drugs of any kind approved for use in the U.S. by the Food and Drug Administration. 

“Stuff happens in any operation. The animals get sick,” Trushenski said. “When that happens, you need effective tools to treat it. But there are no tools in the tool chest right now for this sector. That really makes it difficult for the industry to thrive and we want to help change that.” 

In fresh water aquaculture operations, such as the common catfish, hybrid striped bass and shrimp farms around the area, the FDA has approved about nine different products for farmers to treat their animals when needed. They have access to sedatives, spawning aids and a couple different antibiotics, including Aquaflor that can prevent a catastrophic die-off event. 

One of the reasons marine aquaculture has no approved tools is the complexity of the approval process, Trushenski said. For instance, a drug approved for use in dogs can be tested in one breed of dog and found to be acceptable for use in all breeds. But fish require much more complex testing, she said. 

“With dogs, a dog is a dog is a dog,” Trushenski said. “But a fish is not a fish. If you want a drug approved for fish you have test it on a minimum of two cold-water species, two cool-water and two warm-water species, for starters. And for each one, you have to gather data that show the drug’s effectiveness, the animal safety, the human food consumption safety and other factors. So it’s huge amounts of data, and it’s very costly and specialized.” 

Another reason for the absence of such tools is, at least for now, the low economic incentive for large pharma companies to pursue the marine aquaculture market. Such companies sell far more of their products, for example, for cattle farming than for aquaculture, Trushenski explained, which makes it difficult for the companies to justify spending many millions of dollars on development and testing of aquaculture products. 

“For fish, it costs the companies a lot of money to get anything approved and they won’t sell near as much, so they don’t get their money back quickly,” she said. 

It’s a bit of a Catch-22 situation: lack of tools makes marine aquaculture riskier, which in turn keeps the number of such operations low, while the low number of farms keeps the economic incentive to develop tools low, as well.   

It’s a bad situation, given that United States currently imports about 90 percent of its seafood; the second-most imported item behind oil. Aside from regulatory issues, other factors keeping marine aquaculture from flourishing in the United States include lack of feed supply and ready access to fingerlings to restock, Trushenski said. 

“But a non-existent medicine chest is a big factor,’ she said. “Right now, if the animals in your marine aquaculture operation get sick you kind of just have to take your lumps. There’s always something waiting for fish to become vulnerable. Stress, moving them, an abrasion on the skin or in the gills…” 

To receive FDA approval, researchers must present data from five major areas, including the effectiveness of the drug and environmental impact, for example. In the case of Aquaflor, its manufacturer already has much of this data available because of its approved use in freshwater aquaculture here and its use in both freshwater and marine aquaculture in other countries. 

A key, missing piece of the puzzle for its approval for marine aquaculture here in the United States, however, is the animal health portion. The team’s goal, therefore is to complete the research in this narrow portion of the required data set needed for approval. Basically, the experiments they will run are designed to prove the drug can be administered to the two species they are working with – cobia and pompano – without harming them. 

To accomplish this, the group will perform a series of fairly straight-forward studies, giving one group of fish no drug, another group the recommended dosage, and two other groups three times and five times the recommended dosage, respectively. The researchers will then watch the fish for health issues. 

After this “in life” phase of the study, conducted at Virginia Tech’s marine aquaculture facilities, a government-contract histologist will examine fish tissue from the various groups, looking for abnormalities or pathological changes in their brain, eye, liver, skin, intestine, muscle, stomach and other tissues. 

“We’re hoping our work will satisfy that requirement, and that in turn will get the approval process moving forward,” Trushenski said. “It’s the FDA’s charge to take a precautionary approach and protect the lives of the American people. But we’re eating this food, treated with this drug, anyway. It’s just coming from other countries. 

“This would be the very first drug approval of any kind for marine aquaculture in this country. It would be huge,” Trushenski said. “It will finally put a tool in the tool box.”