Fuel use and metabolic response to endurance exercise: a wind tunnel study of a long-distance migrant shorebird

• DOI: 10.1242/jeb.205.16.2453
• Publication Date: 2021-04-25T05:04:56Z
• Authors: Susanne Jenni-Eie...; Lukas Jenni; Anders Kvist; Åke Lindström; Theunis Piersma; G. Henk Visser
• Keywords: Glycerol; 0106 biological sciences; bird; BLOOD PARAMETERS; PROTEIN; Fatty Acids, Nonesterified; Lipoproteins, VLDL; migration; 01 natural sciences; Birds; Physical Conditioning, Animal; energy expenditure; THYROID-HORMONES; Animals; Triglycerides; protein catabolism; PLASMA-GLUCOSE; Calidris canutus; 3-Hydroxybutyric Acid; red knot; plasma metabolite; lipid catabolism; BIRD FLIGHT; MUSCLE; RECOVERY; MIGRATORY FLIGHT; Uric Acid; flight; HOMING PIGEONS; Animal Migration; Energy Metabolism; GAS-EXCHANGE

SUMMARY This study examines fuel use and metabolism in a group of long-distance migrating birds, red knots Calidris canutus (Scolopacidae), flying under controlled conditions wind tunnel for up to 10 h. Data are compared with values resting birds fasting the same time. Plasma levels free fatty acids, glycerol uric acid were elevated during flight, irrespective flight duration (1-10 h). Triglyceride levels, estimated concentration very-low-density lipoproteins (VLDLs) β-hydroxybutyrate lower while glucose did not change. In plasma lipid catabolites positively correlated residual variation body mass loss, energy expenditure (as measured using doubly labelled water method), after removing effect initial mass. The metabolite indicate: (i) that rates catabolism lipids from adipose tissue protein higher flight; (ii) low ketone concentrations probably facilitate release tissue; (iii) triglyceride VLDL do indicate an additional pathway delivery, as found small birds; and(iv) relationships between expenditure, loss metabolic pattern suggest individual entails rate both shift substrate.