The study was conducted in eight bottlenose dolphins housed in managed care at Kolmården Zoo, Sweden and Oceanogràfic Aquarium, Spain, from June to December 2023.
Experimental procedure
Following an overnight fast, the dolphin was positioned at the side of the pool and was allowed to spontaneously breathe through a custom-made pneumotachometer for a period between 5-7 minutes, during which the respiratory flows and expired gas composition were measured. Then it was given a predetermined quantity of food and metabolic measurements were repeated after 30, 60, 90 and 120 minutes.
Data analysis and statistics
From the measurement of the oxygen consumption, the basal metabolic rate and peak metabolic rate after feeding were calculated and compared to estimate the heat increment of feeding.
A generalized additive model was used to investigate the relationship between oxygen consumption and various predictor variables such as sex, energy intake, age, body mass and pool temperature.