A gut feeling about abalone

South African marine biotechnologists have found a way to harness mother nature to improve the artificial existence of farmed abalone, the shellfish delicacy in huge demand in Japanese and Chinese restaurants. Laboratory research at the University of Cape Town is on the brink of providing abalone farmers with a major economic edge in the competitive global industry. Probiotics to the rescue.

Good bacteria

"It all developed from an academic point of view," explained Dr Vernon Coyne of the Molecular and Cell Biology Department at UCT. "We asked the question - because abalone are grazers, feeding on plants - do they require bacteria in their digestive tracts which would enable them to break down kelp and other seaweeds, similar to cows requiring bacteria in their rumen to break down grass?"

The answer was yes: "we were able to show that in fact abalone do have bacteria associated with their digestive tract and these bacteria are active in their gut and produce enzymes which enable them to digest the seaweed."

Then it was a case of how to apply this new knowledge. Soon Dr Coyne and his team of post-graduate students were extracting those useful intestinal bacteria, working out which ones most benefited the tasty mollusk's digestion and experimenting with various cocktails of intestinal bacteria known as probiotics. Think of probiotics as a sort of immune booster for the shellfish, which enables them to cope with the stresses and infections of a crowded life in a factory farm.

Probiotics

Mark Miles is an entrepreneur with many careers tucked under his belt. Among other things, he started a small aquaculture enterprise, where seawater is recycled six times among huge blue plastic tanks containing abalone at various stages of their life cycle, from nearly invisible larvae to hand-sized shelled creatures. Miles stood in the grading room of Global Ocean, where workers assess the size of the animals, and praised the science of probiotics.

"We are just moving into the probiotic era," said Miles. "It is a world wide solution to improving the growth rates of a variety of creatures. It is a very natural process, very organic and it is ensuring that the right bacteria enters the food chain. The early tests are showing that it makes a significant difference. We can increase growth rates by some 30 to 40 percent."

Probiotics have a significant advantage over antibiotics. Both are meant to kill off infection - a particular fear in the unusual environment of factory farming. But antibiotics wipe out all bacteria, good and bad, and can be transferred to the animal at the top of the food chain, namely, humans.

Most probiotics are simply versions of useful bugs we already have in our stomachs, and picky consumers are far happier about purchasing meat or fish treated with probiotics. In contrast, the European Union has virtually outlawed the use of antibiotics in imported food.

"In [the field of] probiotics generally the world is possibly more advanced than we are," said Miles. "But in aquaculture and particularly in abalone, UCT lead the world in this research. They have spent the time analyzing the naturally occurring bacteria in abalone guts. They have isolated those and they have selected those most beneficial to growth and they are continually finding new ones and improving all the time."

Andre Bok, an abalone farm manager in the small seaside town of Kleinmond, displays what looks like thin, stiff, light brown rectangles of dried meat in his hands.

Good food for the "cow of the sea"

"This is artificial abalone food, it is made out of mainly kelp and it is a big advantage for abalone farmers to have an artificial food. First of all when the weather is rough and you can't get the natural food from the wild you can still feed the abalone even though the sea conditions don't allow you to go out and get it."

The kelp strips are impregnated with probiotics. The cautious abalone have to be taught to eat it but soon catch on. Bok slips the strip under the bubbling surface of the water in a nearby plastic tank. Two eye stalks immediately come out from a shell and a two and a half year old abalone smaller than a saucer seizes the dried kelp. "Also, artificial food is an advantage because we can add all sorts of things to it, like probiotics, which make it more nutritious for the abalone and so allow the abalone to grow faster and be healthier and just be a stronger animal," said Bok. "That enables every abalone farm a lot more productivity."

Bok also used the dairy analogy: "an abalone is like a cow of the sea. Like a cow, it eats the grass and allows it almost to ferment in the stomach." Kelp on its own is not particularly nutritious. A large abalone farm can require 25 tons of it a week. So anything which makes best use of this resource gives abalone farmers another advantage.

Industrial-level production.

"The research has gone from laboratory scale through to small farm trials," says Dr Coyne. "We are now at the stage where we are looking at putting together a pilot plant."

He has been approached by abalone farmers in Chile and Mexico, other countries where poaching and pollution has severely damaged the shellfish in its natural habitat. In South Africa, some estimates are that abalone, which can require over a decade to reach sexual maturity, will not exist in the wild within three to four years. This research will at least keep abalone alive in a more domesticated setting, while decreasing the industry's production costs and providing employment.

"I see this research as keeping abalone alive within a specific environment in the industry," says Dr Coyne. "Probiotics would be something that South Africa could export, it would make good economic sense. The secret would be to remain ahead of other food producers, to generate second and third generation probiotics for abalone and other seafood."

Coyne thinks marine biotechnology is set to soar, especially given the long South African coastline, the biodiversity, and the potential talent in the country, which includes Phd student Brett Macey, whose studies concentrated on the correct combination of probiotics for artificial - as opposed to kelp-fed - abalone.

"There's a shortage of seaweed these days and the advantage of an artificial diet is that you know exactly what is in it and how much the animals are getting," said Macey, perched on the edge of an abalone creche - seawater tanks filled with rows of corrugated plastic sheets, dotted with minute abalone, the size of a baby's thumbnail. 

"It is fantastic to see that your work actually has value and that people are actually using it."

Both men enjoy the scope of the field. "Basically it is a discipline which addresses the entire spectrum of issues, from food shortages, in terms of protein for developing countries, right through to new biotech compounds from marine animals,' said Coyne. "It's everything from medicine to nutrition."

More information:

Dr Vernon Coyne: vernon@science.uct.ac.za

www.globalocean.co.za

March 2004