Stress-related changes in adrenal glands of stranded Harbour Porpoises (Phocoena phocoena) on the Dutch coast.

Abstract

Stranded harbour porpoises (Phocoena phocoena) are submitted for post-mortem investigation to the Veterinary Pathological Diagnostic Centrum (VPDC) of the Department Pathobiology at the Utrecht University (UU). The main purpose of this investigation is to determine the cause of death and is commissioned by the Ministry of Economic Affairs, Agriculture and Innovation (EL&I). In this study the adrenal glands of these harbour porpoises were examined using routine histopathology and linked to the health problems they probably had before they died. Adrenal glands are releasing stress hormones in stressful situations. When animals suffer from chronic stress, adrenal glands are changing morphologically, histologically and in the way of releasing the stress hormones. In this study the adrenal glands are examined morphological and histological. The hypothesis was that the histological changes correlate with presence and duration of stress as judged by post-mortem investigation. Adrenalitis, congestion, haemorrhage, necrosis, apoptosis, hypertrophy, edema, cysts, extracellular eosinophilic material and vacuolar degeneration were found. All the adrenal glands had one or more of these abnormalities. Several examined examples are probably stress-related. The weights of the adrenal glands of the group with chronic stress were significant heavier than with acute stress. An adrenalitis in the transitional area of adrenal cortex and medulla has never been described in harbour porpoises and is recommended to be further investigated using IHC.