Further investigation of blow or exhaled breath condensate as a non-invasive tool to monitor the physiological response to stressors in cetaceans
Abstract
Anthropogenic and environmental stressors continue to increase and pose significant threats to marine mammals. Noise is a stressor of particular concern especially for the total aquatic cetaceans, since it can affect hearing, navigational abilities, foraging and reproduction. However, noise can also bring about a physiological response that may ultimately impact immune function, metabolism and growth, reproduction and health. Through prior ONR funded efforts, our laboratory has conducted studies on the physiological response to stress in a representative cetacean, the beluga (Delphinapterus leucas). We not only have access to aquarium belugas that allow for "controlled studies" and ease of sampling, but also through collaborations have access to samples from wild belugas. While blood is the "gold standard" for measuring the physiological response to stressors, it requires capture and restraint to obtain samples from free-ranging cetaceans, which in itself can result in a physiologic response. However, prior to ONR funded studies have shown promise in utilizing other less invasive tissue matrices for measurement of hormones and immune components that can be collected from free-ranging cetaceans for example, exhaled breath condensate or blow. We have shown that stress hormones such as cortisol and immune components can be measured in blow form aquarium and live capture-release belugas with changes to controlled stressor scenarios. While our laboratory has made substantial progress in investigating the physiological response to stressors in beluga blow and have shown it holds promise, it became apparent that additional validation steps are needed for complete and accurate interpretation, such as a method to correct for dilution due to water contamination or force of blow form individual whales. Preliminary data from our laboratory shows urea as a promising candidate as a dilution factor for blow; however, further biological validation is necessary. Moreove, additional markers of health and fitness in addition to cortisol are highly likely in blow such as thyroid hormones, which are important for regulating metabolism. Finally, molecular markers of stress and immune system function have yet to be explored in cetacean blow and may prove ideal given the hgih sensitivity and ability to use relatively small quantitites of starting material. The objectives of this proposed project will utilize blow samples from aquarium belugas under controlled scenarios and wild belugas for continued validation of utilizing cetacean blow to investigate the physiological response to stressors in cetaceans. Overall objectives include 1) investigating urea and/or total protein as a suitable marker of dilution in order to standardize samples; 2) investigation of other important markers of fitness in blow such as thyroid hormones; 3) investigation of molecular markers of stress and immune system function in blow; and 4) carrying out initial steps for transition of blow collection to small free-ranging toothed whales. Blow collection is feasible form free-ranging cetaceans and offers promise for monitoring and detecting physiologic responses to stressors, such as sound, in order to inform the Navy and its operations. Moreover, blow collection is a useful tool that is also valuable in Navy relevant controlled acoustic and hearing research studies on managed care cetaceans, offering the ability for immediate physiological assessment after sound exposure.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 04, 2018
- Source ID
- N000141812779
Entities
People
- Tracy Romano
Organizations
- Board of Regents of the University of Michigan
- Office of Naval Research
- United States Navy