A Convenient Dry Feed for Raising Zebrafish Larvae

Five protocols for raising zebrafish larvae were tested and compared in this study. These include four variations of feeding Fry Feed Kyowa N-250 (Kyowa) obtained from Miyako Kagaku, as well as an established protocol using Paramecia and supplemented with Zeigler dry feeds. The performance of these feeding protocols was evaluated using larvae obtained from two wild-type strains AB and AB/TL and two mutant strains gassi and smarca4(a50). Several quality parameters including survival rate, rearing density, growth rate, sex ratio, fecundity, eggs spawned by the resulting fish, and the corresponding survival rate were compared by logistic regression analyses. The results showed that the quality of AB and AB/TL larvae raised using one of the Kyowa feeding protocols was equally good when compared with the standard Paramecium protocol for up to 20 larvae/L. The protocol also provided a comparable but slightly lower survival rate for smarca4(a50) and inbred gassi lines, respectively. Nonetheless, all other quality parameters in the case of gassi were comparable to the established Paramecium protocol, even though the line carried multiple pigmentation mutations. Therefore, the optimized Kyowa feeding protocol can substantially reduce routine workload in maintaining a zebrafish research facility by virtually eliminating the need to culture live Paramecia feed.