Mitochondrial coupling efficiency is the first bioenergetic function to decline at Critical Thermal maximum (CTmax) in the skeletal muscle of a fish, the spirlin (Alburnoides bipunctatus)

Key Points

• This research aims to investigate mitochondrial function in spirlin muscle at varying temperatures, focusing on efficiency at critical thermal maximum (CTmax).
• Tested mitochondrial function at 20°C and CTmax (34°C) in spirlin muscle.
• Measured oxygen fluxes related to oxidative phosphorylation (OXPHOS) and leak.
• Analyzed the efficiency of ATP production during thermal stress.
• At CTmax, oxygen fluxes increased (OXPHOS and LEAK), but coupling efficiency (ATP/O) decreased significantly.
• Muscle mitochondrial dysfunction at high temperatures may hinder locomotion in spirlin.
• Study highlights critical role of mitochondrial efficiency in thermal tolerance.