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Fishing For Vaccines

by the Fish Site Editor
10 April 2006, at 1:00am

By Intervet - Most of us take going for a flu, chickenpox or tetanus shot for granted. Vaccines are for people,right? Wrong, vaccines are also of vital importance in the animal healthcare world, and no more so than in aquaculture. Brian Guest looks at how market leader Intervet is doing its bit to contribute to the blue revolution.

Fishing For Vaccines - By Intervet - Most of us take going for a flu, chickenpox or tetanus shot for granted. Vaccines are for people, right? Wrong, vaccines are also of vital importance in the animal healthcare world, and no more so than in aquaculture. Brian Guest looks at how market leader Intervet is doing its bit to contribute to the blue' revolution. Intervet

With hi-tech fleets emptying the world's oceans at an alarming rate, the old adage "there's plenty more fish in the sea" has a more than hollow ring to it these days. But while stocks of wild fish have continued to take a battering due to over-fishing, modern aquaculture - the farming of fish and shellfish - has successfully stepped into the breach to take up the slack.

In little more than three decades the fledgling industry has experienced explosive growth as it strives to meet the world's voracious appetite for cheap, high protein food. Today, one in four fish bought by the consumer in shops and markets has been reared on a fish farm, while forecasts indicate that two million tons of extra fish will be required each year for the next 30 years, all of which will have to come from aquaculture.

The world's fastest growing form of food production, fish farming is now clocking up annual growth rates of close on 10 percent, compared with growth rates of two percent per annum for farmed terrestrial meat production. Yet with the world's population growing, and rising incomes in the richer countries, sustaining the global demand for seafood puts a heavy burden on an industry which only really got out of the traps 30 years ago.

Modern fish farming brings with it a host of problems that threaten the health of the stocks and could also impact upon the environment. High densities of fish in small pens and cages translate into high incidences of disease. Sea lice, the aquaculture equivalent of ticks in cows, are one such problem. In fact, disease decimates more than a third of all farmed fish and shrimp before it reaches marketable size - a mind-boggling loss to the worldwide industry of upwards of USD 9 billion.

"Effective disease control is vital if this industry is to prosper," says Alistair Brown, Director of Intervet's Aquatic Animal Health (AAH) division, headquartered in Boxmeer, the Netherlands, which produces a range of aquatic animal health products, including vaccines, disinfectants, anti-infectives and reproduction aids aimed at controlling infectious diseases and improving the welfare of captive stocks.

Brown, a veteran in the fish farming business who was there in his wellies in Scotland in 1974 when the first 30 tons of pen-reared salmon were harvested, and who joined Intervet in 1995, says the business has changed beyond recognition since those heady days. "We literally started from scratch, we made our own cages, feeds, everything," he recalls. "We didn't even know if we could farm salmon, and most people believed it impossible.

Now we are talking about an industry producing 1.8 million tons a year (mostly Atlantic salmon but also including other salmonid species like rainbow trout). Although fish have been farmed for 4,000 years, we never had any idea about diseases.

"To begin with, farms mainly used antibiotics to combat disease. Now the approach is far more sophisticated with greater emphasis on achieving the right environmentally responsible balance between breeding conditions, improved nutrition, feed developments and the all-round health of the stocks. That's where Intervet's expertise comes in."

Better, cleaner, safer

Alistair Brown (top) and William Enright are pictured, along with a number of fish farming images which show a research farm used by Intervet near Bergen in Norway, tilapia being harvested in Asia, young salmon being vaccinated, a black tiger shrimp and hatching salmon.
Since the industry's pioneering beginnings in the early 1970s, the regulatory environment has become far more stringent, particularly in leading aquaculture countries such as Norway, Chile, Scotland, Canada, the Faroe Islands and Ireland. Antibiotic use - once a favorite target for critics of the industry - is one such example of an issue which is no longer on the agenda, because for a large part it has been replaced by effective disease control with vaccines. "In 1987, Norway produced 50 thousand tons of salmon using 50 tons of antibiotics in the process - that's around 0.6 grams per kilo of salmon," says Brown. "Today, its output of salmon has jumped to close on half a million tons, but with the industry only using 600 kilos of antibiotics."

Economically, aquaculture offers significant advantages over other forms of intensively farmed meat production. Besides a growing appeal to an increasingly health-conscious public because it is rich in fatty acids, minerals and vitamins, it is simply far more efficient to farm fish than to farm terrestrial-based meat animals.

In the USA, aquaculture production now exceeds the combined production of lamb, mutton and veal. Fifty percent of this production is catfish reared on 150 square miles of ponds. And it is less of a burden on perhaps the world's most precious commodity - clean water.

Says Brown: "It takes 1,000 tons of water to produce a ton of wheat. In feedlot beef production it takes seven kilos of grain to produce each additional kilo of live weight. In pork production the ratio is 4 to 1, poultry 2.2 to 1 and in catfish only 1.7 to 1. The food conversion of fish is very good. OK, fishmeal from wild fish accounts for about 30-40 percent of the feed, but that's only for carnivorous fish like salmon and it's decreasing all the time. And don't forget, close to 80 percent of all farmed fish worldwide are herbivores. Mostly carp farmed in Asia for local consumption."

Since acquiring Norwegian salmon vaccine company Norbio in 1993, Intervet AAH's expansion has kept stride with the rapid growth of the industry. The division now employs around 50 people, mostly at its two major research and development centers in Bergen, Norway, and the Singapore center which opened just over two years ago.

"Our largest center, Bergen, focuses on cold water species such as salmon, trout, halibut and cod," explains Marketing and Pharmaceutical Manager Dr William Enright, "while Singapore's main focus is on Asian species such as groupers, Asian sea bass, yellowtail, flatfish, tilapia and shrimp. "Besides vaccines for the Japanese market, Singapore is doing a great deal of epidemiology, identifying pathogens and trying to develop an effective response to them. The trouble is that most people rearing fish in the Asia Pacific region don't know what the specific problems are that affect their stock. With the exception of Japan, Asia doesn't really have a fish vaccine culture. That's a challenge. So we're not only developing vaccines, we're having to educate and train people about vaccinology."

Tip of an iceberg

According to Enright, the total global market for fish vaccines is currently only around EUR 60 million. Salmon-related products, particularly vaccines, account for the bulk of Intervet AAH's income to date and it is a clear market leader in salmonid products.

"In fact, we have almost 70 percent of the Norwegian market," adds Enright. "But you need to put that into perspective because salmon farming only represents two percent of all farmed fish. More than 80 percent of all aquaculture in the world - and I'm talking about several hundred fish and shrimp species - is in Asia. Much of the production in the world comes from carp, kept in a pond in the garden for local consumption, but vital to the rural communities of China and India."

Developing effective vaccines is a long and knowledge-intensive process - it can take anything from between four and eight years - but the result has been the controlling of diseases such as furunculosis and vibriosis that once threatened to stop the salmon aquaculture industry in its tracks. "The vaccine antigens we produce, such as against Vibrio, Aeromonas and Moritella bacterial species, are extremely effective, while the viral vaccines certainly reduce mortality substantially," says Brown.

"We've never had an outbreak of a major bacterial disease in salmon vaccinated with our oil-based vaccines. Furthermore, we are the only company to have a live attenuated bacterial vaccine, used in U.S. catfish, and we were first to launch a recombinant viral vaccine eight years ago." The major fish species vaccinated today are salmon and trout, sea bass and sea bream, Channel catfish and yellowtail. Although there are several ways to administer vaccines, most young fish continue to be vaccinated by hand. In Norway, for example, nearly 200 million fish are vaccinated each year. Each fish is removed from the water, anesthetized and vaccinated.

Explains Brown: "A team of four can vaccinate something like 50,000 fish a day. In Norway, one company employs about 60 people who travel the length and breadth of the country vaccinating fish. In the early days vets used to do the vaccinating, now that's no longer the case. Nearly all salmon are vaccinated like this before they are transferred from fresh water to seawater."

Lessons learned

Like all new and fast developing industries, Brown says, lessons have to be quickly learned from initial mistakes if the same level of effective disease control is to be put in place in those countries that are new to the fish farming business.

"What's happened historically in Scotland and Norway will probably be repeated in countries such as Canada and Chile. You can expect particular diseases to crop up when a certain intensity of farming has been reached, but you still have to be prepared for any kind of eventuality. It's a challenge to introduce the same range of vaccines in all salmon-producing countries.

"Chile, for example, which produces nearly 500,000 tons of farmed salmon and trout a year, only started using vaccines on a large scale relatively recently. If a new disease surfaces there, we have to move quickly to try and identify whether it's a recognizable strain. Often or not it's something we've seen before, say in Norway, and then it's just a regulatory problem. But we still may have to add new components to a recognized vaccine as farmers only want to vaccinate once."

Dogged by bad press in its early years, Brown says that while aquaculture still needs to put its house in order in a few contentious areas before it truly comes of age, it is moving quickly in the right direction, helped in no small part by the scientific expertise of companies like Intervet. "Vaccines have led to a significant reduction in the need for antibiotics and chemicals, and we're now starting to target dedicated species, including shrimp, which is highly susceptible to disease. We're seeing vast improvements in the governing of aquaculture and in the quality of the product. In Chile, for example, we sell vaccines in the fish. In other words, vaccination is carried out by an Intervet-contracted team and this is included in the price of the vaccine. By doing so, we're able to maintain control over the process."

As wild stocks continue to fall, aquaculture production looks set to quadruple in the coming 30 years. For Alistair Brown and William Enright, the only conclusions that can be drawn are positive. "This is a highly complex business," concludes Brown, "but it's one which is not going to go away. The number of species farmed will continue to grow. Companies are already diversifying away from salmon to fish such as cod, halibut, sturgeon, even tuna. The future looks very bright for the industry."

Source: Intervet - April 2006

the Fish Site Editor