Wine waste as fish fodder

In an industry first, the South Australian Research and Development Institute (SARDI) has partnered with Barossa Valley company Tarac Technologies to develop wine waste into aquaculture feed for abalone.

The pioneering project is off to a good start and according to researchers, lab trials in South Australia have shown that the winemaking by-product known as ‘grape marc’ (registered as Acti-Meal) outperformed commercial aquaculture feeds for abalone growth – at almost half the price.

Who would have thought that heat-treated grape skins, pulp, seeds and stems would be a better and cheaper form of fish fodder?

During a three-month trial, greenlip abalone fed on an experimental formulated diet containing 5-20 per cent Acti-Meal at a water temperature of 22°C. This improved the growth performance and feed utilisation of juvenile greenlip abalone compared to a commercial diet.

“As we added the grape marc we saw a significant improvement in growth and feed utilisation,” says SARDI Nutrition and Feed Technology expert, Associate Professor David Stone (pictured).

“They all grew well – there was no impact on the health of the animals and survival was 100 per cent. The other bonus was we removed something that cost $500-$800 a tonne and replaced it with what was effectively a waste product that costs $250-$400 a tonne – it’s a price reduction with a growth benefit.”

He added that cereals such as wheat, lupins and soy were traditionally used as a carbohydrate and energy source in commercial abalone feed. And Acti-Meal had the potential to replace some of those ingredients.

Tarac produces about 130,000 tonnes of steam-distilled grape marc a year and already use their waste for products such as feed for cattle, sheep and pigs.

A six-month trial of a test feed produced by Aquafeeds Australia containing 20 per cent Acti-Meal is set to begin at an abalone farm in November.

The farm trial is being funded by a $100,000 grant through the South Australian River Murray Sustainability Program and the laboratory study was funded through the South Australian Government Functional Food Focus Program.