Comparative mechanisms for O storage and metabolism in two Florida diving birds: the anhinga (Anhinga anhinga) and the double-crested cormorant (Nannopterum auritum).

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Auteurs principaux: White, Jeff, Schell, Elizabeth R, Dawson, Neal J, McCracken, Kevin G
Format: Artículo científico
Langue:en
Publié: Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology 2025
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author White, Jeff
Schell, Elizabeth R
Dawson, Neal J
McCracken, Kevin G
author_facet White, Jeff
Schell, Elizabeth R
Dawson, Neal J
McCracken, Kevin G
White, Jeff
Schell, Elizabeth R
Dawson, Neal J
McCracken, Kevin G
collection PubMed - marine biology
contents Comparative mechanisms for O storage and metabolism in two Florida diving birds: the anhinga (Anhinga anhinga) and the double-crested cormorant (Nannopterum auritum). White, Jeff Schell, Elizabeth R Dawson, Neal J McCracken, Kevin G Animals Diving Oxygen Birds Muscle, Skeletal Oxygen Consumption Pectoralis Muscles Male Air-breathing vertebrates face many physiological challenges while breath-hold diving. In particular, they must endure intermittent periods of declining oxygen (O) stores, as well as the need to rapidly replenish depleted O at the surface prior to their next dive. While many species show adaptive increases in the O storage capacity of the blood or muscles, others increase the oxidative capacity of the muscles through changes in mitochondrial arrangement, abundance, or remodeling of key metabolic pathways. Here, we assess the diving phenotypes of two sympatric diving birds: the anhinga (Anhinga anhinga) and the double-crested cormorant (Nannopterum auritum). In each, we measured blood- and muscle-O storage capacity, as well as phenotypic characteristics such as muscle fiber composition, capillarity, and mitochondrial arrangement and abundance in the primary flight (pectoralis) and swimming (gastrocnemius) muscles. Finally, we compared the maximal activities of 10 key enzymes in the pectoralis, gastrocnemius, and left ventricle of the heart to assess tissue level oxidative capacity and fuel use. Our results indicate that both species utilize enhanced muscle-O stores over blood-O. This is most apparent in the large difference in available myoglobin in the gastrocnemius between the two species. Oxidative capacity varied significantly between the flight and swimming muscles and between the two species. However, both species showed lower oxidative capacity than expected compared to other diving birds. In particular, the anhinga exhibits a unique diving phenotype with a slightly higher reliance on glycolysis and lower aerobic ATP generation than double-crested cormorants.
format Artículo científico
id pubmed_39704814
institution PubMed
language en
publishDate 2025
publisher Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology
record_format pubmed
spellingShingle Comparative mechanisms for O storage and metabolism in two Florida diving birds: the anhinga (Anhinga anhinga) and the double-crested cormorant (Nannopterum auritum).
White, Jeff
Schell, Elizabeth R
Dawson, Neal J
McCracken, Kevin G
Animals
Diving
Oxygen
Birds
Muscle, Skeletal
Oxygen Consumption
Pectoralis Muscles
Male
Comparative mechanisms for O storage and metabolism in two Florida diving birds: the anhinga (Anhinga anhinga) and the double-crested cormorant (Nannopterum auritum). White, Jeff Schell, Elizabeth R Dawson, Neal J McCracken, Kevin G Animals Diving Oxygen Birds Muscle, Skeletal Oxygen Consumption Pectoralis Muscles Male Air-breathing vertebrates face many physiological challenges while breath-hold diving. In particular, they must endure intermittent periods of declining oxygen (O) stores, as well as the need to rapidly replenish depleted O at the surface prior to their next dive. While many species show adaptive increases in the O storage capacity of the blood or muscles, others increase the oxidative capacity of the muscles through changes in mitochondrial arrangement, abundance, or remodeling of key metabolic pathways. Here, we assess the diving phenotypes of two sympatric diving birds: the anhinga (Anhinga anhinga) and the double-crested cormorant (Nannopterum auritum). In each, we measured blood- and muscle-O storage capacity, as well as phenotypic characteristics such as muscle fiber composition, capillarity, and mitochondrial arrangement and abundance in the primary flight (pectoralis) and swimming (gastrocnemius) muscles. Finally, we compared the maximal activities of 10 key enzymes in the pectoralis, gastrocnemius, and left ventricle of the heart to assess tissue level oxidative capacity and fuel use. Our results indicate that both species utilize enhanced muscle-O stores over blood-O. This is most apparent in the large difference in available myoglobin in the gastrocnemius between the two species. Oxidative capacity varied significantly between the flight and swimming muscles and between the two species. However, both species showed lower oxidative capacity than expected compared to other diving birds. In particular, the anhinga exhibits a unique diving phenotype with a slightly higher reliance on glycolysis and lower aerobic ATP generation than double-crested cormorants.
title Comparative mechanisms for O storage and metabolism in two Florida diving birds: the anhinga (Anhinga anhinga) and the double-crested cormorant (Nannopterum auritum).
topic Animals
Diving
Oxygen
Birds
Muscle, Skeletal
Oxygen Consumption
Pectoralis Muscles
Male
url https://pubmed.ncbi.nlm.nih.gov/39704814/