Feeding increases MyoD and PCNA expression in myogenic progenitor cells of Notothenia coviiceps

Oxygen consumption and ammonia excretion of the Antarctic fish Notothenia coriiceps (18.4 cm LF) increased respectively two and fourfold above fasting levels 24 h after feeding with a single meal of shrimps (5.5 to 7.5% of body mass), and remained elevated for 120 h. In fasted fish, c‐met positive cells in the fast muscle represented 5.5% of the total number of myonuclei. The number of c‐met positive cells staining for the proliferating cell nuclear antigen was increased by 60% both 24 and 96 h after the meal, while the number of cells expressing the myogenic transcription factor, MyoD, was increased by 20% after 24 h, and by 44% after 96 h. The total numbers of c‐met positive cells and cells expressing myogenic were not significantly altered 96 h following feeding. The results are consistent with an activation of myogenic progenitor cells proliferation by feeding but suggest a relatively long cell cycle time.