Artificial hatching substrate, effect on RNA / DNA ratio and protein retention during the yolk-sac period of Atlantic salmon (Salmo salar)

Abstract

Genetical groups of Atlantic salmon (Salmo salar) were hatched in a Caiifonian hatching system with and without an astro-turf artificial hatching substrate, and were later transfered to separate feeding units. The substrate reared (ATR) alevins grew faster, absorbed the yolk faster and more efficient, and absorbed protein from the yolk faster and more efficient, than flat screen reared (FSR) alevins. Protein synthesis, RNA content, DNA content, and the RNA-DNA ratio were higher in favour of the substrate reared alevins. The differeces in disfavour of the FSR alevins are probably due to high activity stress. After commencement of first feeding the ATR fry grew faster, and RNA content and DNA content were higher than in the FSR fry. However a difference in specific growth rate in favour of the FSR fry was observed at the end of the experiment. The RNA-DNA ratio was in favour of the ATR fry immediatly after commencement of first feeding, but in favour of the FSR fry at the end of the experiment.