Abalone feed development in South Africa

Lourens de Wet and Krishen Rana wrote the original article for International Aquafeed.

Over the past decade South African aquaculture has improved significantly, since the 1990s there has been a rapid growth in the development of commercial aquaculture. A recent benchmark survey by the Aquaculture Institute of South Africa (AISA) showed that aquaculture was growing by the rate of eight percent in production and 32 percent in value respectively, between 2005 and 2008.

The development of aquaculture in South Africa was originally targeted at the high value imports. This was achieved with commercially relevant freshwater species like Rainbow trout, Carp and with marine species such as mussels, oysters and abalone. Abalone production dominated aquaculture in South Africa, representing 24 percent of total tonnage and 82 percent of the total value of aquaculture.

One of the aquafeed manufactures supporting this sector in the Western Cape is NutroScience, which dominate supply in the aquafeed market in South Africa and also contribute to aquafeed exports. Also supporting the Western cape aquafeed industry technically is the University of Stellenbosch and Rhodes (Grahamstown), which has good facilities and product development and evaluation, they also provide research and training.

The University of Stellenbosch feed technology group focus on reducing the environmental impact of aquaculture by developing low polluting feeds and environmentally sustainable feeding practices. The utilisation of food processing and industrial by-products streams as alternative feed ingredients for fishmeal and fish oil in marine finfish feeds. Enriching aquafeed towards long shelf life and performance.

In the case of feed for Abalone 50 percent is fed on wild collected macro algae every 48 hours, and the other 50 percent is grown with artificial dry feeds fed every 24 to 48 hours. The use of macro algae is nearing its limits on availability so using artificial dry feeds to feed abalone is the way forward.  Also moisture loss can be controlled via the diet.

Abalone are slow feeders, so their feed needs to be stable in water for up to 24 or even 48 hours to allow good feeding response by all animals in a system. The cost spent on binding the feed for abalone is more than R7million annually, contributing to 25 - 45 percent of the cost of various feeds. So the effort is on reducing the cost of binding the feed or improving the water stability of the feed and this will have a direct effect on the cost of abalone production.

Over the past three years such a strategy has been used and the abalone feed cost has been reduced to below R14 per kg, without compromising production performance. The work continues to reduce costs and make the abalone aquaculture industry still more cost effective and competitive.

NutroScience supported this article and it can be found at International aquafeed online magazine, issuu and docstoc