Diel and circadian analysis of clock gene transcripts in central and peripheral tissues in the Atlantic salmon (Salmo salar)

Atlantic salmon (Salmo salar) pre-smolt optic tectum, saccus vasculosus and gill tissues were collected over a light:dark (LD, 8:16) cycle, constant light (LL) and constant dark (DD) time series at a four hour resolution Total RNA was extracted, RNA quality was assessed using BIORAD Experion, then submitted to a bespoke clock gene NanoString CodeSet Atlantic salmon (Salmo salar) were raised under LL, then placed under a light dark cycle (LD, 8:16) for 8 weeks before being transferred to constant light or constant darkness. Serial tissue samples were collected (optic tectum, saccus vasculosus and gill; snap frozen) to assess the expression of clock genes in response to fluctuating and constant lighting conditions. Food was removed 48h before the first sampling point, tank water temperature was maintained at 14oC. Dark samples were collected under red light.