Diet and temperature modify the relationship between energy use and ATP production to influence behaviour in zebrafish (Danio rerio)

Food availability and temperature influence energetics of animals, and can alter behavioural responses such as foraging and spontaneous activity. Food availability, however, is not necessarily a good indictator of energy (ATP) available for cellular processes. The efficiency of energy transduction from food-derived substrate to ATP in mitochondria can change with environmental context. Our aim was to determine whether the interaction between food availability and temperature affects mitochondrial efficiency and behaviour in zebrafish (Danio rerio). We conducted a fully factorial experiment to test the effects of feeding frequency, acclimation temperature (three weeks to 18 or 28°C), and acute test temperature (18 and 28°C) on whole-animal oxygen consumption, mitochondrial bioenergetics and efficiency (ADP consumed per oxygen atom; P:O ratio), and behaviour (boldness and exploration). We show that infrequently fed (once per day on four days per week) zebrafish have greater mitochondrial ...