title: Pregnancy limits lung function during exercise and depresses metabolic rate in the skink Tiliqua nigrolutea.
abstract: High gestational loads have been associated with a range of ecological costs, such as decreased locomotor ability; however, the physiological mechanisms that underpin these changes are poorly understood. In this study, breathing patterns, metabolic rates, lung volume and lung diffusing capacity were measured at rest and during exercise in the pregnant skink Tiliqua nigrolutea. Breathing patterns were largely unaffected by gestation; however, decreases in metabolic rate (rate of oxygen consumption) in the late stages of pregnancy induced a relative hyperventilation. The reductions in metabolic rate during late pregnancy prevent the calculation of the maintenance cost of pregnancy based on post-partum and neonatal metabolic rates. Despite the high relative litter mass of 38.9±5.3%, lung diffusing capacity was maintained during all stages of pregnancy, suggesting that alterations in diffusion at the alveolar capillary membrane were not responsible for the relative hyperventilation. Lung volume was increased during pregnancy compared with non-pregnant females, but lung volume was significantly lower during pregnancy compared with post-partum lung volume. Pregnant females were unable to produce the same metabolic and ventilatory changes induced by exercise in non-pregnant females. This lack of ability to respond to increased respiratory drive during exercise may underpin the locomotor impairment measured during gestation in previous studies.
authors: Biomedical Sciences, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia suzy.munns@jcu.edu.au.
authors: Suzanne L
authors: SL
authors: Munns
authors: School of Biological Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia.
authors: Ashley
authors: A
authors: Edwards
authors: School of Biological Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia.
authors: Stewart
authors: S
authors: Nicol
authors: School of Biological Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia.
authors: Peter B
authors: PB
authors: Frappell
mesh_terms: D000818:Animals; D001481:Basal Metabolism; D005260:Female; D008116:Lizards / Q000502:physiology*; D008168:Lung / Q000502:physiology; D010805:Physical Conditioning, Animal; D012098:Reproduction; D012119:Respiration; D012129:Respiratory Function Tests
keywords: Breathing pattern; Cost of pregnancy; Gestation; Lizard; Lung diffusion capacity; Lung volume; Oxygen consumption; Pulmonary gas exchange; Reptile; Ventilation