Advancement of rotifer culture and manipulation techniques in Europe

Abstract

Since no artificial feed formulation for first feeding of marine larval fish has been developed yet, live prey feeding remains essential in commercial marine hatchery operations. Because Ž . cultured rotifers are relatively poor in eicosapentaenoic acid EPA: 20:5n-3 and docosahexaenoic Ž . acid DHA: 22:6n-3 , it is essential and therefore common practice to enrich these live prey with emulsions of marine oils. The short-term exposure to oil emulsions results in lipid-encapsulated rotifers with high EPA and DHA levels. However, these rotifers are prone to fast losses of their gut content and show a distortion in their proteinrlipid balance. Rather than submerging rotifers in oil emulsions, it is often preferred to use formulated culture diets when medium to low enrichment values are needed in live prey. The use of these diets contributes not only to the filling of the gut of the rotifers with nutrients, it generally creates a more stable entire body composition which is important especially when rotifers are not consumed immediately by the larvae.New culture techniques for rotifers, such as closed recirculation systems, are offering new possibilities for continuous supplies of high quality rotifers at 10 times higher densities than in batch cultures. The production increase in these systems is explained by the better water quality obtained by the introduction of protein skimmers, ozone treatment, and biological filtration. Although disinfection of rotifers remains a bottleneck, it has been observed that rotifer populations cultured at high densities are not prone to higher bacterial infestation. Also, the problem of unexplained mortalities in batch cultures seems to be partly solved by the introduction of Ž . recirculation systems or by bacterial management introduction of probionts , which allow more reliable rotifer production. q

Total lipids content and fatty acids composition of the rotifer Brachionus plicatilis using artificial enrichments

“…There are several advantages to rotifers such as they are easy and cheap to cultivate in mass quantities on baker's yeast (Hirata and Mori, 1967;Kitajima et al, 1979;Hirata, 1980), they are of adequate size for the first stage of rearing of small fish larvae (Watanabe et al,1983) and their high nutritional value and digestibility (Lubzens et al, 1985;Kestemont and Awaiss, 1989). In the following decades of the global aquaculture explosion, rotifers were used extensively as an early-starter live food (Hirata, 1980;Watanabe et al,1983;Lubzens, 1987;Lubzens et al,1989;Dhert et al, 2001) for a wide variety of very promising (at the time) potential marine finfish candidates for aquaculture, such as turbot (Scophthalmus maximus) (Bromley and Howel,1983); gobies (Gobio gobio) (Kestemont and Awais;1989); seabass (Dicentrarchus labrax) (Gatepouse and Luquet,1981); gillhead seabream (Spaurus aurata) (Chatain and Ounais-Guschemann, 1990;Divanach and Kentouri, 2000;Pousao-Ferreira et al, 2003); plaice (Pleuronectes platessa) (Howel, 1973;Bromley and Howell, 1983); and Ayu (Plecoglossus altivelis) (Oka et al,1980;Teshima et al, 1987); Atlantic cod (Rosenlund and Halldorsson, 2007;Maehre et al, 2013) .…”

Effects of dietary microalgae on growth, survival and fatty acid composition of sea urchin Paracentrotus lividus throughout larval development

“…High mortalities during larviculture of marine fish and shellfish remain a major bottleneck in aquaculture that limits production (Dhert et al, 2001). Larval nutrition and the provision of optimal feeds are known to be a key factor in overcoming these problems .…”

Artemia replacement in co-feeding regimes for mysis and postlarval stages of Litopenaeus vannamei: Nutritional contribution of inert diets to tissue growth as indicated by natural carbon stable isotopes

“…The nonfeeding naupliar stages are followed by the phytoplankton-feeding zoea and the carnivorous mysis stages, the latter being highly dependant on a constant supply of live feed, which is generally provided as rotifers and Artemia nauplii. Although live diets represent advantages such as high digestibility and stability in the water, rotifers and Artemia may lack essential nutrients for marine organisms (Léger et al 1986;Webster and Lovell, 1990;Dhert et al, 2001). In this context, the development of nutritionallycomplete microdiets that can partially substitute live feed in co-feeding regimes presents economic and environmental advantages.…”