Rearing zebrafish (Danio rerio) larvae without live food: evaluation of a commercial, a practical and a purified starter diet on larval performance

Owing to the increasing importance of zebrafish as a vertebrate model in many fields of research, efforts must be made to breed and maintain this species in laboratory. Zebrafish larvae are traditionally reared on cultured live paramecia during the first 9 days of exogenous feeding, followed by a combination of paramecia and artemia nauplii until day 21, making larval rearing expensive, labour intensive and unpredictable. Thus, a trial was conducted with zebrafish larvae in order to evaluate the suitability of artificial diets as an alternative to live food during the first 21 days of exogenous feeding. Five dietary treatments were tested: (1) artemia nauplii; (2) a commercial; (3) a purified; (4) a practical diet, all delivered continuously; (5) the same practical diet delivered manually. The best overall larval performance was achieved in the group fed artemia nauplii (86% survival, 14.3 mm standard length, 46.1 mg wet weight). Compared with existing results obtained with the traditional live food schedule, our results suggest that paramecia might not be the most suitable first food for zebrafish, and that artemia nauplii could be used as the only live food. The present work demonstrates that zebrafish larvae can be reared without live food with a significant growth and a high survival, provided that an appropriate artificial diet is presented in a continuous way. Among the diets tested, the practical diet, if continuously delivered, led to the best performance assuring a mean standard length of 72% of that obtained with artemia and a similar survival rate. Moreover, the purified diet, supporting over 50% survival and an appreciable growth, could be useful in some toxicological studies in which a well‐defined diet is needed.