BREEDING IN BOXES, IS IT ETHICAL?

Pair breeding of zebrafish  Danio rerio enables the generation of progeny with known genetic parentage and is essential for in vivo research. This  practice is routinely carried out in small transparent breeding boxes with no water flow or filtration.

These breeding boxes typi cally contain less than one liter of water and this small volume increases the potential for fluctuations in water quality and the  absence of filtration allows accumulation of toxic waste products from fish metabolism. This unstable environment  compared to normal filtered systems has the potential to impact breeding performance, cause harm to the fish  and also affect the quality of the science.

Factors such as timing of feeding before breeding and degradation of the water quality are poorly investigated, r ecommendations for best practice are highly variable and reliant on anecdotal information.

In this trial fish were split into 3 groups. Group A were fasted for 30 hours before being placed in to boxes. Group B were given their normal morning feed and then placed into boxes after 6 hours. Group C were fed to satiation 10 minutes prior to being placed into the boxes. The fish were subdivided into  transparent or black breeding boxes, both static and on a water flow through system. The fish were left overnight and water quality tested at 18 hours, 22 hours and 26 hours post transfer.  In addition to water quality,  adult behavior and embryo quality and quantity were also assessed.