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Top Story: Feds take a hard look at veterinary drugs

FDA’s efforts to restrict antibiotics in food animals don’t stop at the shoreline

By James Wright
March 01, 2014

Food-animal producers have a formidable foe, one that’s everywhere they look yet too small to see. Bacteria, the most abundant biomass on Earth, serve many essential functions for the existence of life. But staying ahead of harmful, illness-causing microorganisms has long been a challenge for farmers both on land and sea, and it may get tougher now that the U.S. Food and Drug Administration (FDA) wants fewer antibiotics to enter the food supply. 

Acknowledging that humans may build resistance to medically important drugs that are also being administered to animals, the food-safety agency in December launched an initiative to curtail veterinary drug use, starting with the manufacturers. While the FDA asked for their voluntary participation, and is thus far getting it, the usage of veterinary drugs on farms — both terrestrial and aquatic — is anything but voluntary. Producers must administer antibiotics, most commonly through feed, strictly according to the directions on the label. Domestically, it must be done under the supervision of a veterinarian. 

“Drug-resistance concerns are driven by drug-use practices upstream,” says William Flynn, deputy director for science policy at the FDA’s Center for Veterinary Medicine, adding that full implementation is expected by 2017. “We consider aquaculture as producing food animals, just like cattle, pigs and poultry. There are differences and commonalities.” 

While fish has barely been mentioned in the growing global discussion about antibiotic use, it’s important to remember that aquaculture produces roughly half of the world’s seafood supply, and antibiotics play a key role in protecting crops and producers’ economic viability. Commercial-scale finfish aquaculture would struggle without veterinary drugs, although there are exceptions where little to no antibiotics or other chemicals are employed (see chart).

The good news is that consumption of farmed seafood poses little risk regarding exposure to veterinary drug residues. That’s due to constantly improving practices on the water, according to one of seafood’s toughest critics, the Monterey Bay Aquarium in Monterey, Calif. Strict limits on antibiotics, or even bans on certain types — both of which could happen in the future — aren’t likely to bring seafood supplies to a screeching halt. 

“Aquaculture has better [drug] management characteristics than traditional livestock,” says Peter Bridson, the aquarium’s aquaculture research manager, who’s focused his attention on salmon farming over the past few years. He also notes that drug use may have different impacts in aquatic environments. 

Aquaculture is a “challenging sector” to get good data for veterinary drug use, but Bridson has found salmon farming to be fairly transparent. Seafood Watch, the aquarium’s sustainable seafood buying-recommendation program for consumers that evaluates such data, has simple goals for veterinary drug use in aquaculture. 

“We’d like to see, ideally, a ban on ‘critically important’ antibiotics and strong limits on the ‘highly important’ ones,” he says, referring to the two categories FDA separates antibiotics into. “One answer is, ‘Let’s ban antibiotics completely and not take that risk,’ or to simply not waste them on food animals. But you have to be pragmatic about farming. Those animals are going to get sick from time to time. Some proper [antibiotic] use has to be OK along the line. One of the problems is prophylactic use, and antibiotics used as a growth promoter. That’s a big problem. Aquaculture has not done that so much.” 

No easy solutions  

Clear pathways for drug-resistance transferral from terrestrial livestock to humans are well documented, Bridson says, adding that antibiotics have been overprescribed for humans as well. The FDA considers all antibiotics important, says Flynn. 

“We’ve known about overuse for some time now. From a scientific point of view, there isn’t a debate,” adds Urvashi Rangan, Ph.D., director of the consumer safety and sustainability group for Consumer Reports. “There aren’t any antibiotics being developed anymore. We don’t have a lot of options after this; it’s a bit of a catch-22. We can’t use these things indiscriminately. It’s about preserving what we’ve got.” 

The salient question, on the farm level, is what separates responsible use from abuse, says marine microbiologist Stephen Newman, president and CEO of Aquaintech in Lynnwood, Wash. 

“To me, what constitutes responsible use is identifying the cause of a specific disease, determining whether it’s amenable to treatment with approved antibiotics or antivirals, and treating the population with the appropriate [drug] for the appropriate amount of time, with the legal withdrawal time,” he says. “When in fact, that’s unfortunately rarely the case. We’re more regulated in the United States, and it’s harder to get antibiotics to use inappropriately. I have a good idea of what is going on globally and yes, in some parts of the world, the vast majority is irresponsible use.” 

Aquaintech provides a range of aquaculture consulting services and water-quality enhancement products that reduce the amount of accumulated organic material in aquatic environments like fish and shrimp ponds as well as products that enhance feed digestibility for animals with short intestinal tracts, like shrimp. Antibiotics, Newman says, cut costs and can be the difference between staying in business or not. His example: Think of telling a rural shrimp farmer in Asia not to use a drug that will save an entire crop needed to support his family. 

“It’s a complicated situation with no easy solutions,” he says. “The approach of bans is fine. However it doesn’t distinguish between legitimate use and abuse. Too many people are forced to use antibiotics simply because they have no choice. It’s harder to enforce that in countries where corruption is the norm.” 

But not impossible: In many cases, small-scale producers do get their advice from salesmen instead of scientists, says Tim Fitzgerald, senior policy specialist for Environmental Defense Fund in Washington, D.C. During the World Wildlife Fund’s Pangasius Dialogues, a gathering of industry, environmental groups and academia to create sustainable aquaculture practices, he heard that rampant antibiotic use was one of the industry’s biggest problems in Vietnam. 

“The overwhelming majority of use was not for properly diagnosed conditions, or even applied by anyone with training in aquatic animal health,” he says. “Given how many Vietnamese pangasius farms have now committed to the [Aquaculture Stewardship Council] standard, I think there is real potential for change in the industry.” 

What most critics of veterinary drugs would like to see, at the very least, is use on an as-needed basis, or only when the animals get sick. Veterinary oversight is required for administering drugs, but Rangan and other critics of overseas operations want more data and transparency. The FDA’s initiative, which she says should be mandatory, is a “stop-gap” measure. 

“And that’s fine. But how will we know what the vet is doing? That’s the challenge in this, knowing exactly what they’re going to be doing, how much they’re prescribing. I don’t know how they’ll do that abroad; there are inherent challenges built into [the FDA] plan. We want to see more information out there and we’ve been asking for this for a long time,” says Rangan. “Policy takes a long time to put in place. If [the FDA] doesn’t get any traction, they’ll move to rulemaking.” 

According to Flynn, the FDA is working with international organizations like Codex, the World Health Organization and OIE (The World Organisation for Animal Health, based in Paris) to harmonize veterinary drug administration standards. 

Whether the FDA has the ability and agility to enforce its mandates has already come under question. The Natural Resources Defense Council in late January released a study that contends the agency failed to remove 30 antibiotic-based livestock feed products from the market after federal investigators found they did not meet regulatory standards for protecting human health. 

Tricky questions  

Newman, however, applauds the FDA for banning chloramphenicol, an antibiotic that’s reportedly cheap and easy to manufacture. According to a report by the University of California-Davis, the rise of “misuse” of antibiotics in food can be traced back to 2001, when the EU found the substance in farmed seafood from Asia. Canada and the United States also found traces of chloramphenicol and subsequently prohibited its use. 

Other banned substances include nitrofurans, an antimicrobial that leaves lingering residues in animal tissues and is considered carcinogenic. “There’s zero tolerance for these things now,” Newman says. 

Retailers like Whole Foods Market have implemented policies regarding substances like antibiotics and growth hormones. The company does not buy any fish or shrimp that are fed antibiotics intended for growth enhancement. “If fish require treatment with medications prohibited by Whole Foods Market (e.g., antibiotics), the pen/tank/pond/raceway must be marked for identification and fish from that system cannot be sold to Whole Foods Market,” the company’s policy states. 

There are ways to avoid antibiotics, says Dick Martin, president of Black Pearl Seafood in Boston, which imports “antibiotic-never” farmed salmon from Scotland. 

“The biggest principle is stocking density and proximity to other [farms],” says Martin, just days after returning from a visit to his source in the Shetland Islands. Too many fish in one area creates stress, he says, which leads to illness and antibiotic use as a “crutch.” The rush to increase volume and maximize profits led to massive disease problems in Chile, Canada and eastern Maine. “They stuffed more fish in the pens to create more biomass, more revenue and it blew up in their face.” 

Martin also worries about antibiotics leaching into the environment through uneaten feed that falls to the ocean floor. “That antibiotic residue is going somewhere,” he says, echoing the concerns of multiple environmental groups. 

Many salmon farming sites in Scotland, Maine and other locations are positioned where swift-moving tidal currents can more effectively disperse effluent. Fallowing, or allowing sites to remain empty for periods of time, is another technique aquaculture operations have employed to strengthen biosecurity. 

How deep will the FDA’s antibiotic initiative go? Can the seafood industry, and consumers for that matter, rely on the agency to ensure that the fish on their plates meet federal safety standards? Rangan of Consumer Reports has her doubts. 

“How the FDA guidance will impact imported seafood without a lot being inspected is a tricky question,” she says. “I don’t think we have an answer about how it is or isn’t going to be affected.” 

Bacteria, fungi and other microorganisms common in marine environments are “very clever” and pose challenges for aquaculture operators to contain. There’s a reason for that, says Newman. “They’ve been around for 3 billion-plus years,” he says. “It’s a pretty good indication of success.”  

Email Senior Editor James Wright at jwright@divcom.com 

Find other SeaFood Business articles discussing antibiotics here.

February 2014 - SeaFood Business  

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