1 NOVEMBER 1998
SPECIALTY FEEDS IN MARINE LARVICULTURE
P. Coutteau, M. Dehasque, T. De Wolf, C. Nys, J.V. Assche
The latest production data of salmon in Norway (>300,000 mt), seabass/seabream in the Mediterranean region (>60,000 mt) and penaeid shrimp in Asia and Latin America (>700,000 mt worldwide) are a few cases illustrating the potential of aquaculture as a successful bio-industry. In this regard, the dependable availability of fry to stock the grow-out ponds or cages is one of the most critical factors in the commercial success of marine fish and shrimp farming. Furthermore, the increasing threat by disease outbreaks has stressed the importance of good-quality fry, balanced nutrition and adequate husbandry. The nutrition of sensitive larval stages at an industrial scale is a major bottleneck, in particular for marine species. Intensive research over the past two decades has resulted in a range of specialty feeds which have improved the cost-efficiency and dependability of the production of fish and shrimp fry, including culture/enrichment diets for the currently used live feeds (the brine shrimp, Artemia, and the rotifer, Brachionus plicatilis) and artificial diets that supplement/ substitute the live feeds in early stages. The application of the brine shrimp, Artemia as live prey in hatcheries for shrimp and fish has benefited from the selection of appropriate strains and new techniques for disinfection, hatching, enrichment and harvesting. The need for micro-algae in the mass-production of rotifers has been eliminated by the development of appropriate culture diets and techniques. In shrimp hatcheries, the use of balanced micro-encapsulated diets and the control of the microbial environment has allowed to completely substitute live micro-algae and partially substitute Artemia. Current research efforts are directed towards replacing Artemia at an earlier age in marine fish larvae (early weaning). The risk for disease outbreaks has promoted the search for special compounds (so called immunostimulants) that improve directly or indirectly the resistance to infection by pathogenic bacteria and viruses. Despite the methodological difficulties encountered to evaluate the efficiency of these compounds, preliminary results indicate that the sensitivity to stress and/or disease of fish and shrimp fry can be improved under laboratory as well as field conditions. This paper presents some recent advances made in the development of specialty feeds for marine aquaculture.
(Inve Technologies N.V., Oeverstraat 7, B-9200 Baasrode, Belgium)