Improved protocol for rapid zebrafish growth without reducing reproductive performance

Abstract

Despite widespread use of zebrafish Danio rerio (Hamilton) as a model organism for finfish aquaculture, genetics and molecular biology, husbandry methods and nutrition have not been standardised. We characterise a protocol for rearing zebrafish using a recently developed combination of environmental parameters that yield rapid growth rates: high densities of live food organisms (marine rotifers and brine shrimp nauplii), low salinity, continuous light and algal turbidity during larval and early juvenile stages (5–21 days post fertilisation, dpf) followed by a transition to conventional rearing methods (dark/light photoperiod, freshwater). We assessed a range of larval fish densities in a stagnant water system with continuous ad libitum feeding until 21 dpf and periodic water changes. Fish stocking densities of 12–22 fish/L gave maximum growth rate and growth rate declined as stocking density increased past this threshold. Survival rates during 5–21 and 21–42 dpf were 87 ± 9 and 98 ± 3% respectively. Mean ± SD weight and length were 64 ± 9 mg and 19.4 ± 1.0 mm at 21 dpf and 245 ± 28 mg and 30.4 ± 1.5 mm at 42 dpf. Fertility was assessed at 66 ± 3 dpf. Mean clutch size was 232 ± 124 oocytes/female and fertilisation rate was 72 ± 16%. This protocol will significantly increase productivity in zebrafish facilities.