1 National Institute of Aquatic Resources, Technical University of Denmark2 Section for Ecosystem based Marine Management, National Institute of Aquatic Resources, Technical University of Denmark3 National Food Institute, Technical University of Denmark4 Division of Industrial Food Research, National Food Institute, Technical University of Denmark5 Section for Marine Ecology and Oceanography, National Institute of Aquatic Resources, Technical University of Denmark6 Wageningen IMARES7 National Institute for Agronomic Research8 National Institute of Sciences and Technologies of the Sea9 BioMar A/S
To sustain eel aquaculture, development of reproduction in captivity is vital. The aim of this review is to assess our current knowledge on the nutrition of broodstock eels in order to improve the quality of broodstock under farming conditions, drawing information from wild adult eels and other marine pelagic spawners. Freshwater eels spawn marine pelagic eggs with an oil droplet (type II), and with a large perivitelline space. Compared with other marine fish eggs, eel eggs are at the extreme end of the spectrum in terms of egg composition, even within this type II group. Eel eggs contain a large amount of total lipids, and a shortage of neutral lipids has been implied a cause for reduced survival of larvae. Eel eggs have higher ARA but lower EPA and DHA levels than in other fish. Too high levels of ARA negatively affected reproduction in the Japanese eel, although high levels of 18:2n‐6 in the eggs of farmed eels were not detrimental. The total free amino acid amount and profile of eel eggs appears much different from other marine pelagic spawners. Nutritional intervention to influence egg composition seems feasible, but responsiveness of farmed eels to induced maturation might also require environmental manipulation. The challenge remains to succeed in raising European eel broodstock with formulated feeds and to enable the procurement of viable eggs and larvae, once adequate protocols for induced maturation have been developed.
Aquaculture Nutrition, 2013, Vol 19, Issue supplement s1, p. 1-24