Pulmonary ventilation–perfusion mismatch : a novel hypothesis for how diving vertebrates may avoid the bends

© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Proceedings of the Royal Society B: Biological Sciences 285 (2018): 20180482, doi:10.1098/rspb.2018.0482.Hydrostatic lung compression in diving marine mammals, with collapsing alveoli blocking gas exchange at depth, has been the main theoretical basis for limiting N2 uptake and avoiding gas emboli (GE) as they ascend. However, studies of beached and bycaught cetaceans and sea turtles imply that air-breathing marine vertebrates may, under unusual circumstances, develop GE that result in decompression sickness (DCS) symptoms. Theoretical modelling of tissue and blood gas dynamics of breath-hold divers suggests that changes in perfusion and blood flow distribution may also play a significant role. The results from the modelling work suggest that our current understanding of diving physiology in many species is poor, as the models predict blood and tissue N2 levels that would result in severe DCS symptoms (chokes, paralysis and death) in a large fraction of natural dive profiles. In this review, we combine published results from marine mammals and turtles to propose alternative mechanisms for how marine vertebrates control gas exchange in the lung, through management of the pulmonary distribution of alveolar ventilation (Embedded Image) and cardiac output/lung perfusion (Embedded Image), varying the level of Embedded Image in different regions of the lung. Man-made disturbances, causing stress, could alter the Embedded Image mismatch level in the lung, resulting in an abnormally elevated uptake of N2, increasing the risk for GE. Our hypothesis provides avenues for new areas of research, offers an explanation for how sonar exposure may alter physiology causing GE and provides a new mechanism for how air-breathing marine vertebrates usually avoid the diving-related problems observed in human divers.Funding to support a portion of this work was obtained by the Fundación Oceanogràfic and by the Office of Naval Research (ONR YIP Award no. N000141410563 and Award no. N000140811220)

Comparative Study of Semen Parameters and Hormone Profile in Small-Spotted Catshark (Scyliorhinus canicula): Aquarium-Housed vs. Wild-Captured

[EN] Comprehensive knowledge of chondrichthyan reproductive biology is crucial for the development of reproductive technologies. For that reason, a male reproductive evaluation was performed on the basis of a comparison of samples collected from wild-captured and aquarium-housed small-spotted catshark (Scyliorhinus canicula). Semen quality, sperm morphometry, and reproductive hormones were assessed. The results demonstrate good in vitro semen quality in aquarium-housed sharks, although there was lower plasma testosterone. Several chondrichthyan species are threatened, and we must increase our knowledge of their reproductive biology in order to establish assisted reproductive protocols for ex situ or in situ endangered species. The small-spotted catshark (Scyliorhinus canicula) is one of the most abundant shark species of the Mediterranean coast and is easy to maintain in aquaria; therefore, it is considered an ideal reproductive model. This study aimed to compare S. canicula male reproductive function in aquarium-housed (n = 7) and wild-captured animals, recently dead (n = 17). Aquarium-housed animals had lower semen volume (p = 0.005) and total sperm number (p = 0.006) than wild-captured animals, but similar sperm concentrations. In terms of sperm parameters, aquarium-housed sharks showed higher total sperm motility (p = 0.004), but no differences were observed regarding sperm viability, mitochondrial membrane potential, or membrane integrity. A morphometric study pointed to a significantly longer head (p = 0.005) and acrosome (p = 0.001) in wild-captured animals. The results of the spermatozoa morphological study of S. canicula were consistent with previous results obtained in other chondrichthyan species. With regard to sex hormones, testosterone levels were significantly lower in aquarium-housed animals (p & LE; 0.001), while similar levels of 17 beta-estradiol and progesterone were found. In short, the present study provides evidence of good in vitro semen quality in S. canicula housed in an aquarium, underlining their excellent potential for application in reproductive technologies for this and other chondrichthyan species.Muñoz-Baquero, M.; Marco-Jiménez, F.; Garcia-Domínguez, X.; Ros-Santaella, JL.; Pintus, E.; Jiménez-Movilla, M.; García-Párraga, D.... (2021). Comparative Study of Semen Parameters and Hormone Profile in Small-Spotted Catshark (Scyliorhinus canicula): Aquarium-Housed vs. Wild-Captured. Animals. 11(10):1-14. https://doi.org/10.3390/ani11102884114111

Dolphin-WET—Development of a Welfare Evaluation Tool for Bottlenose Dolphins (Tursiops truncatus) under Human Care

Ensuring high standards of animal welfare is not only an ethical duty for zoos and aquariums, but it is also essential to achieve their conservation, education, and research goals. While for some species, animal welfare assessment frameworks are already in place, little has been done for marine animals under human care. Responding to this demand, the welfare committee of the European Association for Aquatic Mammals (EAAM) set up a group of experts on welfare science, cetacean biology, and zoo animal medicine across Europe. Their objective was to develop a comprehensive tool to evaluate the welfare of bottlenose dolphins (Tursiops truncatus), named Dolphin-WET. The tool encompasses 49 indicators that were either validated through peer review or management-based expertise. The first of its kind, the Dolphin-WET is a species-specific welfare assessment tool that provides a holistic approach to evaluating dolphin welfare. Inspired by Mellor’s Five Domains Model and the Welfare Quality®, its hierarchical structure allows for detailed assessments from overall welfare down to specific indicators. Through combining 37 animal-based and 12 resource-based indicators that are evaluated based on a two- or three-level scoring, the protocol offers a detailed evaluation of individual dolphins. This approach allows for regular internal monitoring and targeted welfare management, enabling caretakers to address specific welfare concerns effectively

S1-tortuga parenquima carbacol 10 μM 1 from Pulmonary ventilation–perfusion mismatch: a novel hypothesis for how diving vertebrates may avoid the bends

Video showing contraction of loggerhead sea turtle lung parenchyma when exposed to carbachol (parasympathetic) at a concentration of 10μ

Efectos de la vibración sobre la actividad del rectus abdominis y sobre la transmisión de aceleraciones durante la realización de un puente frontal

Whole-body vibration exercise have been widely used during the last two decades, with most scientific publications reporting various positive effects. Most commonly, squat exercises have been studied. Instead, this study explored the rectus abdominis activity and the transmission of sinusoidal vibration to the human body during the performance of front bridges on a oscillating vibration platform at different frequencies (5, 16, 20 Hz) with constant amplitude (3 mm). Maximal vibration-induced accelerations at the head (axis X, Y, Z) and mean electromyographic activity were assessed in thirty-one healthy subjects using a skin-mounted triaxial accelerometer and surface electromyography. A damping coefficient was calculated for each axis as the difference between platform and head maximal accelerations. Rectus abdominis activity and the damping coefficients in the axis X and Z significantly increased with each increment in the platform vibration frequency (p < 0.001). It is concluded that a front bridge on an oscillating vibration platform vibrating at 16-20 Hz is effective to activate significantly the rectus abdominis muscles in the studied population.Durante las dos últimas décadas se ha incrementado notablemente la utilización de la vibración como medio complementario de ejercicio físico. La literatura científica muestra distintos efectos positivos, aunque la mayor parte de ensayos se han centrado en el análisis del ejercicio de squat. El objetivo del presente estudio fue analizar la actividad muscular del rectus abdominis y la transmisión de la vibración en el cuerpo humano durante la realización de un puente frontal sobre una plataforma vibratoria oscilante vibrando a diferentes frecuencias (5, 16, 20 Hz) y a una amplitud constante (3 mm). Las aceleraciones máximas en la cabeza (ejes X, Y, Z) y la actividad electromiográfica media del rectus abdominis fueron determinadas en 31 sujetos sanos por medio de un acelerómetro triaxial y electromiografía de superficie. Para cada eje se calculó un coeficiente de amortiguación restando la aceleración máxima registrada en la cabeza a la aceleración máxima registrada sobre la plataforma. La actividad electromiográfica del rectus abdominis y los coeficientes de amortiguación en los ejes X y Z aumentaron significativamente con cada incremento en la frecuencia de vibración de la plataforma (p < 0.001). Se concluye que el puente frontal sobre plataforma vibratoria a las frecuencias de 16-20 Hz constituye un ejercicio eficaz para reclutar las fibras musculares del rectus abdominis en la población de estudio

Dolphin-WET—Development of a Welfare Evaluation Tool for Bottlenose Dolphins (<i>Tursiops truncatus</i>) under Human Care

Ensuring high standards of animal welfare is not only an ethical duty for zoos and aquariums, but it is also essential to achieve their conservation, education, and research goals. While for some species, animal welfare assessment frameworks are already in place, little has been done for marine animals under human care. Responding to this demand, the welfare committee of the European Association for Aquatic Mammals (EAAM) set up a group of experts on welfare science, cetacean biology, and zoo animal medicine across Europe. Their objective was to develop a comprehensive tool to evaluate the welfare of bottlenose dolphins (Tursiops truncatus), named Dolphin-WET. The tool encompasses 49 indicators that were either validated through peer review or management-based expertise. The first of its kind, the Dolphin-WET is a species-specific welfare assessment tool that provides a holistic approach to evaluating dolphin welfare. Inspired by Mellor’s Five Domains Model and the Welfare Quality®, its hierarchical structure allows for detailed assessments from overall welfare down to specific indicators. Through combining 37 animal-based and 12 resource-based indicators that are evaluated based on a two- or three-level scoring, the protocol offers a detailed evaluation of individual dolphins. This approach allows for regular internal monitoring and targeted welfare management, enabling caretakers to address specific welfare concerns effectively

Dolphin-WET-Development of a Welfare Evaluation Tool for Bottlenose Dolphins (Tursiops truncatus) under Human Care

The welfare committee of the European Association for Aquatic Mammals (EAAM) set up a group of experts on welfare science, cetacean biology, and zoo animal medicine across Europe to develop a comprehensive tool to evaluate the welfare of bottlenose dolphins (Tursiops truncatus) under human care named Dolphin-WET. The tool encompasses 49 indicators (i.e., 37 animal-based and 12 resource-based indicators) inspired by Mellor's Five Domains Model and the Welfare Quality ®. The Dolphin-WET is a species-specific and individual-based welfare assessment tool that provides a holistic approach to evaluating bottlenose dolphins' welfare. Ensuring high standards of animal welfare is not only an ethical duty for zoos and aquariums, but it is also essential to achieve their conservation, education, and research goals. While for some species, animal welfare assessment frameworks are already in place, little has been done for marine animals under human care. Responding to this demand, the welfare committee of the European Association for Aquatic Mammals (EAAM) set up a group of experts on welfare science, cetacean biology, and zoo animal medicine across Europe. Their objective was to develop a comprehensive tool to evaluate the welfare of bottlenose dolphins (Tursiops truncatus), named Dolphin-WET. The tool encompasses 49 indicators that were either validated through peer review or management-based expertise. The first of its kind, the Dolphin-WET is a species-specific welfare assessment tool that provides a holistic approach to evaluating dolphin welfare. Inspired by Mellor's Five Domains Model and the Welfare Quality ®, its hierarchical structure allows for detailed assessments from overall welfare down to specific indicators. Through combining 37 animal-based and 12 resource-based indicators that are evaluated based on a two- or three-level scoring, the protocol offers a detailed evaluation of individual dolphins. This approach allows for regular internal monitoring and targeted welfare management, enabling caretakers to address specific welfare concerns effectively