AUTHOR=Fahlman Andreas , Borque-Espinosa Alicia , Facchin Federico , Fernandez Diana Ferrero , Caballero Paola Muñoz , Haulena Martin , Rocho-Levine Julie 

TITLE=Comparative Respiratory Physiology in Cetaceans

JOURNAL=Frontiers in Physiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.00142

DOI=10.3389/fphys.2020.00142

ISSN=1664-042X

ABSTRACT=<p>In the current study, we used breath-by-breath respirometry to evaluate respiratory physiology under voluntary control in a male beluga calf [<italic>Delphinapterus leucas</italic>, body mass range (<italic>M</italic><sub>b</sub>): 151–175 kg], an adult female (estimated <italic>M</italic><sub>b</sub> = 500–550 kg) and a juvenile male (<italic>M</italic><sub>b</sub> = 279 kg) false killer whale (<italic>Pseudorca crassidens</italic>) housed in managed care. Our results suggest that the measured breathing frequency (<italic>f</italic><sub>R</sub>) is lower, while tidal volume (<italic>V</italic><sub>T</sub>) is significantly greater as compared with allometric predictions from terrestrial mammals. Including previously published data from adult bottlenose dolphin (<italic>Tursiops truncatus</italic>) beluga, harbor porpoise (<italic>Phocoena phocoena</italic>), killer whale (<italic>Orcinus orca</italic>), pilot whale (<italic>Globicephala scammoni</italic>), and gray whale (<italic>Eschrichtius robustus</italic>) show that the allometric mass-exponents for <italic>V</italic><sub>T</sub> and <italic>f</italic><sub>R</sub> are similar to that for terrestrial mammals (<italic>V</italic><sub>T</sub>: 1.00, <italic>f</italic><sub>R</sub>: −0.20). In addition, our results suggest an allometric relationship for respiratory flow (<inline-formula><mml:math id="INEQ1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mi>V</mml:mi><mml:mo>.</mml:mo></mml:mover></mml:math></inline-formula>), with a mass-exponent between 0.63 and 0.70, and where the expiratory <inline-formula><mml:math id="INEQ2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mi>V</mml:mi><mml:mo>.</mml:mo></mml:mover></mml:math></inline-formula> was an average 30% higher as compared with inspiratory <inline-formula><mml:math id="INEQ3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mi>V</mml:mi><mml:mo>.</mml:mo></mml:mover></mml:math></inline-formula>. These data provide enhanced understanding of the respiratory physiology of cetaceans and are useful to provide proxies of lung function to better understand lung health or physiological limitations.</p>