Vitamin A physiology in the precocious harbour seal (Phoca vitulina): a tissue-based biomarker approach

2002 ◽  
Vol 80 (9) ◽  
pp. 1511-1519 ◽  
Author(s):  
Lizzy Mos ◽  
Peter S Ross
Keyword(s):  
Vitamin A ◽  
Marine Mammals ◽  
Relevant Information ◽  
Phoca Vitulina ◽  
Retinyl Palmitate ◽  
Harbour Seal ◽  
Natural Processes ◽  
Reproductive Endocrine ◽  
Positive Correlations ◽  
Free Ranging

Vitamin A is a nutrient essential to all mammals for growth and development, as well as for the maintenance of reproductive, endocrine, and immune systems. Environmental contaminant-related disruption of vitamin A has been observed in many wildlife species and can therefore be used as a biomarker of toxic effects. However, the natural processes regulating vitamin A uptake, storage, and distribution among compartments are poorly understood in marine mammals. In this study, 20 young healthy harbour seals (Phoca vitulina) were captured to establish a compartment-based model providing a foundation for a mechanistic understanding of vitamin A physiology and disruption. Vitamin A (retinol, retinyl palmitate, and (or) retinoic acid) was quantified in blood plasma and in biopsy samples of liver, blubber, and skin. Although the highest concentrations of vitamin A were found in liver, blubber represents a more important storage depot, with an estimated 66% of the total retinoid content of the compartments measured. We suggest that vitamin A physiology in the precocious harbour seal has evolved to deal with high vitamin A availability during a short nursing period and to sustain growth during the postweaning fast. Positive correlations in vitamin A concentrations among liver, blubber, and skin support the use of less invasive biopsy sampling of just blubber or skin, which can provide physiologically relevant information in biomarker studies of free-ranging marine mammals.

Developmental changes in circulatory vitamin A (retinol) and its transport proteins in free-ranging harbour seal (Phoca vitulina) pups

2000 ◽  
Vol 78 (10) ◽  
pp. 1862-1868 ◽  
Author(s):  
Wendy Simms ◽  
Peter S Ross
Keyword(s):  
Vitamin A ◽  
Marine Mammals ◽  
Environmental Contaminants ◽  
Phoca Vitulina ◽  
Transport Proteins ◽  
Developmental Changes ◽  
Harbour Seal ◽  
Retinol Binding Protein ◽  
Free Ranging ◽  
The Impact

Although vitamin A (retinol) levels are highly regulated within individual organisms, natural (e.g., age, sex, disease) and anthropogenic (e.g., environmental contaminants) factors can affect the dynamics of this essential nutrient. In this study, we examined developmental changes in the circulatory vitamin A system of free-ranging harbour seal (Phoca vitulina) pups by collecting serial blood samples from healthy known-age animals throughout their nursing period. While harbour seal pups were born with relatively low levels of circulatory retinol (144.4 ± 13.9 µg/L), nursing animals more than doubled these levels within 2 days (385.0 ± 46.9 µg/L), and levels continued to rise more gradually until weaning (431.0 ± 35.8 µg/L). Animals that were not nursing, such as orphaned (184.4 ± 34.2 µg/L), fasted (347.0 ± 14.4 µg/L), and weaned (204.5 ± 38.5 µg/L) pups, had significantly lower circulatory retinol levels. Despite the developmental changes observed in total retinol, the concentration of retinol bound by its transport proteins, retinol binding protein and transthyretin, remained relatively constant throughout the nursing period. This suggests that, like most mammals, the delivery of retinol to target tissues is highly regulated in harbour seal pups. Furthermore, the high concentrations of circulatory retinol observed in harbour seal pups may serve to saturate transport proteins, ensuring a steady delivery of vitamin A to target tissues during a period of potentially variable supply. Understanding how natural factors affect circulatory retinol and its transport proteins is an important facet of assessing the impact of environmental contaminants on vitamin A dynamics in marine mammals.

scholarly journals Livestock-associated meticillin-resistant Staphylococcus aureus in a young harbour seal (Phoca vitulina) with endocarditis

2019 ◽  
Vol 7 (3) ◽  
pp. e000886 ◽  
Author(s):  
Ana Rubio-Garcia ◽  
John W A Rossen ◽  
Jaap A Wagenaar ◽  
Alex W Friedrich ◽  
Jan H van Zeijl
Keyword(s):  
Staphylococcus Aureus ◽  
Marine Mammals ◽  
Aortic Wall ◽  
Bacterial Culture ◽  
Histopathological Examination ◽  
Phoca Vitulina ◽  
Antimicrobial Treatment ◽  
Harbour Seal ◽  
First Time ◽  
Secondary Bacterial Pneumonia

A five-month-old male harbour seal was admitted for rehabilitation to the Sealcentre Pieterburen on November 16, 2015. During initial veterinary examination parasitic pneumonia and secondary bacterial pneumonia were suspected. Therefore, the seal received antiparasitic and antimicrobial treatment and appeared to recover but died unexpectedly after several weeks. Postmortem examination revealed a perforation in the aortic wall and histopathological examination of the aorta revealed mural necrosis with haemorrhage and suppurative to mixed inflammation. Bacterial culture resulted in isolation of a meticillin-resistant Staphylococcus aureus (MRSA) from the pericardial effusion. Subsequent culture of rectal swabs collected at arrival and during rehabilitation showed that the animal was already colonised with MRSA when admitted to the Sealcentre. MRSA has been isolated from marine mammals before, however, to our knowledge this is the first report of MRSA-associated endocarditis in seals and the first time that livestock-associated MRSA is reported in seals.

Dandy–Walker-Like Malformation in a Free-Ranging Atlantic Harbour Seal Pup (Phoca vitulina concolor)

2020 ◽  
Vol 178 ◽  
pp. 41-45
Author(s):  
M.R. Rivard ◽  
J. Díaz-Delgado ◽  
J. Hammond ◽  
J.E. Flower
Keyword(s):  
Phoca Vitulina ◽  
Harbour Seal ◽  
Free Ranging

The retina of the harbour seal, Phoca vitulina

1971 ◽  
Vol 49 (1) ◽  
pp. 19-23 ◽  
Author(s):  
G. S. Jamieson ◽  
H. D. Fisher
Keyword(s):  
Marine Mammals ◽  
Photoreceptor Cell ◽  
Outer Nuclear Layer ◽  
Cell Types ◽  
Phoca Vitulina ◽  
Inner Nuclear Layer ◽  
Horizontal Cells ◽  
Harp Seal ◽  
Harbour Seal ◽  
Retinal Layers

The structure of the retina of the harbour seal, Phoca vitulina richardii, is described. It is shown that the retina of the harbour seal is similar to that of the harp seal, in that it shows little zonation of the inner nuclear layer, possesses large horizontal cells, and has similar nuclear densities within the different retinal layers throughout the retina. The outer nuclear layer is also the thickest of all the retinal layers. Two types of photoreceptor cell, types B and C, were observed with a ratio of roughly 1:23 respectively. This ratio, along with a well-developed and extensive tapetum, indicates a highly light-sensitive retina. The existence of retinal folding in marine mammals is also questioned and discussed.

scholarly journals Laryngeal and soft palate valving in the harbour seal (Phoca vitulina)

2020 ◽  
Vol 223 (20) ◽  
pp. jeb230201
Author(s):  
Arlo Adams ◽  
Wayne Vogl ◽  
Camilla Dawson ◽  
Stephen Raverty ◽  
Martin Haulena ◽  
...  
Keyword(s):  
Soft Palate ◽  
Marine Mammals ◽  
Vocal Folds ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Upper Aerodigestive Tract ◽  
Laryngeal Inlet ◽  
Harbour Seals ◽  
Lateral Margins ◽  
And Function

ABSTRACTEffective ‘valving’ in the upper aerodigestive tract (UAT) is essential to temporarily separate the digestive and respiratory pathways. Marine mammals are largely dedicated to feeding underwater, and in many cases swallowing prey whole. In seals, little work has been done to explore the anatomy and function of the UAT in the context of valving mechanisms that function to separate food and air pathways. Here we use videofluoroscopy, gross dissection, histology and computed tomography (CT) renderings to explore the anatomy of the larynx and soft palate in the harbour seal (Phoca vitulina), and generate models for how valving mechanisms in the head and neck may function during breathing, phonating, diving and swallowing. Harbour seals have an elevated larynx and the epiglottis may rise above the level of the soft palate, particularly in pups when sucking. In addition, the corniculate and arytenoid cartilages with associated muscles form most of the lateral margins of the laryngeal inlet and vestibule, and move independently to facilitate airway closure. The corniculate cartilages flex over the laryngeal inlet beneath the epiglottis to completely close the laryngeal vestibule and inlet. The vocal folds are thick and muscular and the medial margin of the folds contains a small vocal ligament. The soft palate has well-defined levator veli palatini muscles that probably function to elevate the palate and close the pharyngeal isthmus during feeding. Our results support the conclusion that harbour seals have evolved UAT valving mechanisms as adaptations to a marine environment that are not seen in terrestrial carnivores.

scholarly journals PCB-Related Alteration of Thyroid Hormones and Thyroid Hormone ReceptorGene Expression in Free-Ranging Harbor Seals (Phoca vitulina)

2006 ◽  
Vol 114 (7) ◽  
pp. 1024-1031 ◽  
Author(s):  
Maki Tabuchi ◽  
Nik Veldhoen ◽  
Neil Dangerfield ◽  
Steven Jeffries ◽  
Caren C. Helbing ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Free Ranging
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