Selenium toxicosis in three California sea lions (Zalophus californianus)
Edwards, W.C.; Whitenack, D.L.; Alexander, J.W.; Solangi, M.A.
Veterinary and Human Toxicology 31(6): 568-570
1989
ISSN/ISBN: 0145-6296 PMID: 2617840 Document Number: 331594
In PM examination of two male California sea lions, one of which was found dead and the other had convulsive seizures the day it died, lesions were found in the stomach, spleen and brain. The gastric mucosa was reddened and contained adherent mucus. The stomach of the larger animal contained a small piece of balloon-like material in the pyloric end; the mucosa were red and there was brown necrosis of the tips of the leaves of the stomach. The spleen had a mottled (red and grey) appearance and was contracted. The lesions in the brain of the larger sea lion were perivascular infiltrate of lymphocytes, foci of glial cells, neuronophagia, mild infiltrates of lymphocytes in the meninges, and neuronal degeneration. The brain of the smaller had similar but milder lesions. Both had a mild nonsuppurative encephalitis. Ulcers in the stomach of the smaller animal were chronic, mucosal necrosis and fibroplasia. The lungs of both were hyperaemic, with no lesions of pneumonia. Virology studies were negative. A male California sea lion with a 9-month history of weight loss despite normal appetite, suddenly refused food and the following day went into a grand mal seizure for 5 minutes and died. Moderate multifocal pulmonary emphysema and atelectasis, moderate adrenal exhaustion and mild focal myopathy were found. The skeletal muscle had occasional degenerate myofibres with nuclear proliferation and regeneration. The skeletal muscle findings suggested a nutritional or stress myopathy; the cause of the pulmonary haemorrhage could not be determined. No pesticide residues considered significant were found. There were no detectable residues of neutral, acidic or basic drugs, but the blood, liver and kidney Se contents in these three were significantly elevated. The Se concentrations in the fish fed to these sea lions greatly exceeded the dietary requirements of Se for domestic livestock.