Gestation increases the energetic cost of breathing in the lizard Tiliqua rugosa

Munns, Suzanne L. (2013) Gestation increases the energetic cost of breathing in the lizard Tiliqua rugosa. Journal of Experimental Biology, 216 (2). pp. 171-180.

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View at Publisher Website: http://dx.doi.org/10.1242/jeb.067827
 
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Abstract

High gestational loads result in fetuses that occupy a large proportion of the body cavity and may compress maternal organs. Compression of the lungs results in alterations in breathing patterns during gestation, which may affect the energetic cost of breathing. In this study, the energetic cost of breathing during gestation was determined in the viviparous skink Tiliqua rugosa. Radiographic imaging showed progressive lung compression during gestation and a 30% reduction in the lung inflation index (rib number at which the caudal margin of the lung was imaged divided by total rib number). Pneumotachography and open flow respirometry were used to measure breathing patterns and metabolic rates. Gestation induced a twofold increase in minute ventilation via increases in breathing frequency, but no change in inspired tidal volume. The rates of O2 consumption and CO2 production did not change significantly during gestation. Together, these results suggest that a relative hyperventilation occurs during gestation in T. rugosa, which in turn suggests that diffusion and/or perfusion limitations may exist at the lung during gestation. The energetic cost of breathing was estimated as a percentage of resting metabolic rate using hypercapnia to stimulate ventilation at different stages of pregnancy. The energetic cost of breathing in non-pregnant lizards was 19.96±3.85% of resting metabolic rate and increased threefold to 62.80±10.11% during late gestation. This significant increase in the energetic cost of breathing may have significant consequences for energy budgets during gestation.

Item ID: 27371
Item Type: Article (Research - C1)
ISSN: 1477-9145
Keywords: ventilation, breathing pattern, oxygen consumption, hypercapnia, reptile, lung
Projects and Grants: The Physiological Effects of High Gestational Loads
Date Deposited: 31 May 2013 01:01
FoR Codes: 06 BIOLOGICAL SCIENCES > 0606 Physiology > 060604 Comparative Physiology @ 80%
11 MEDICAL AND HEALTH SCIENCES > 1116 Medical Physiology > 111603 Systems Physiology @ 20%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 80%
97 EXPANDING KNOWLEDGE > 970111 Expanding Knowledge in the Medical and Health Sciences @ 20%
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