Journal Articles

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    Magnetic resonance imaging shows spinal curvature in Chinook salmon (Oncorhynchus tshawytscha) is associated with chronic inflammation of peri-vertebral soft tissues.
    (John Wiley and Sons, Inc., 2024-03-01) Lovett BA; Firth EC; Perrott MR; Munday JS; Pontre BP; Lydon A-MP; Symonds JE; Preece MA; Herbert NA
    Chinook salmon (Oncorhynchus tshawytscha) farmed in New Zealand are known to develop abnormal spinal curvature late in seawater production. Its cause is presently unknown, but there is evidence to suggest a neuromuscular pathology. Using magnetic resonance imaging (MRI), we evaluated the relationship between soft tissue pathology and spinal curvature in farmed Chinook salmon. Regions of interest (ROIs) presenting as pathologic MRI signal hyper-intensity were identified from scans of 24 harvest-sized individuals: 13 with radiographically-detectable spinal curvature and 11 without. ROIs were excised from individuals using anatomical landmarks as reference points and histologically analysed. Pathologic MRI signal was observed more frequently in individuals with radiographic curvature (92%, n = 12) than those without (18%, n = 2), was localized to the peri-vertebral connective tissues and musculature, and presented as three forms: inflammation, fibrosis, or both. These pathologies are consistent with a chronic inflammatory process, such as that observed during recovery from a soft tissue injury, and suggest spinal curvature in farmed Chinook salmon may be associated with damage to and/or compromised integrity of the peri-vertebral soft tissues. Future research to ascertain the contributing factors is required.
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    A lower motor neuron disease in takahē (Porphyrio hochstetteri) is an endoplasmic reticulum storage disease.
    (Taylor and Francis Group, 2023-03-30) Jolly RD; Perrott MR; Alley MR; Hunter SA; Pas A; Beard H; Hemsley KM; Greaves G
    AIMS: To investigate the pathogenesis of a disease in takahē (Porphyrio hochstetteri) with intracytoplasmic inclusion bodies in lower motor neurons. METHODS: Four birds aged between 5 and 12 years, from three different wildlife sanctuaries in New Zealand were examined. Of these, only one had signs of spinal dysfunction in the form of paresis. Stained paraffin sections of tissues were examined by light microscopy and immunostained sections of the ventral horn of the spinal cord by confocal microscopy. Epoxy resin sections of the spinal cord from the bird with spinal dysfunction were examined by electron microscopy. RESULTS: Two types of inclusion bodies were noted, but only in motor neurons of the ventral spinal cord and brain stem. These were large globoid eosinophilic bodies up to 5 µm in diameter, and yellow/brown granular inclusions mostly at the pole of the cell. The globoid bodies stained with Luxol fast blue but not with periodic acid Schiff (PAS), or Sudan black. The granular inclusions stained with Luxol fast blue, PAS and Sudan black. Both bodies were slightly autofluorescent. On electron microscopy the globoid bodies had an even electron-dense texture and were bound by a membrane. Beneath the membrane were large numbers of small intraluminal vesicles. The smaller granular bodies were more heterogeneous, irregularly rounded and membrane-bound accumulations of granular electron-dense material, often with electron-lucent vacuoles. Others were more vesicular but contained varying amounts of electron-dense material. The large globoid bodies did not immunostain for lysosomal markers lysosomal associated protein 1 (LAMP1) or cathepsin D, so were not lysosomal. The small granular bodies stained for cathepsin D by a chromogenic method.A kindred matrix analysis showed two cases to be as closely related as first cousins, and another case was almost as closely related to one of them, but the fourth bird was unrelated to any other. CONCLUSIONS: It was concluded that this was an endoplasmic reticulum storage disease due to a specific protein misfolding within endoplasmic reticulum. It was rationalised that the two types of inclusions reflected the same aetiology, but that misfolded protein in the smaller granular bodies had entered the lysosomal system via endoplasmic reticulum autophagy. Although the cause was unclear, it most likely had a genetic aetiology or predisposition and, as such, has clinical relevance.
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    Per- and polyfluoroalkyl substances (PFAS), trace elements and life history parameters of mass-stranded common dolphins (Delphinus delphis) in New Zealand
    (Elsevier Ltd, 2021-12) Stockin KA; Yi S; Northcott GL; Betty EL; Machovsky-Capuska GE; Jones B; Perrott MR; Law RJ; Rumsby A; Thelen MA; Graham L; Palmer EI; Tremblay LA
    Profiles of 33 PFAS analytes and 12 essential and non-essential trace elements were measured in livers of stranded common dolphins (Delphinus delphis) from New Zealand. PFAS concentrations reported were largely comparable to those measured in other marine mammal species globally and composed mostly of long-chain compounds including perfluorooctanesulfonic acid (PFOS), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA) and perfluorooctanesulfonamide (FOSA). PFAS profiles did not vary significantly by location, body condition, or life history. Notably, significant positive correlations were observed within respective PFAS and trace elements. However, only negative correlations were evident between these two contaminant types, suggesting different exposure and metabolic pathways. Age-associated concentrations were found for PFTrDA and four trace elements, i.e. silver, mercury, cadmium, selenium, indicating differences in the bioaccumulation biomagnification mechanisms. Overall, our results contribute to global understanding of accumulation of PFAS by offering first insights of PFAS exposure in cetaceans living within South Pacific Australasian waters.
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    Fourier transform infrared (FTIR) analysis identifies microplastics in stranded common dolphins (Delphinus delphis) from New Zealand waters
    (Elsevier Ltd, 2021-12) Stockin KA; Pantos O; Betty EL; Pawley MDM; Doake F; Masterton H; Palmer EI; Perrott MR; Nelms SE; Machovsky-Capuska GE
    Here we provide a first assessment of microplastics (MPs) in stomach contents of 15 common dolphins (Delphinus delphis) from both single and mass stranding events along the New Zealand coast between 2019 and 2020. MPs were observed in all examined individuals, with an average of 7.8 pieces per stomach. Most MPs were fragments (77%, n = 90) as opposed to fibres (23%, n = 27), with translucent/clear (46%) the most prevalent colour. Fourier transform infrared (FTIR) spectroscopy revealed polyethylene terephthalate (65%) as the most predominant polymer in fibres, whereas polypropylene (31%) and acrylonitrile butadiene styrene (20%) were more frequently recorded as fragments. Mean fragment and fibre size was 584 μm and 1567 μm, respectively. No correlation between total number of MPs and biological parameters (total body length, age, sexual maturity, axillary girth, or blubber thickness) was observed, with similar levels of MPs observed between each of the mass stranding events. Considering MPs are being increasingly linked to a wide range of deleterious effects across taxa, these findings in a typically pelagic marine sentinel species warrants further investigation.