ACUTE SELENIUM POISONING IN BROILERS

Clinical symptoms, as well as gross- and histopathological alterations have been reported that were observed in a broiler flock during an outbreak of acute selenium poisoning and in chicken experimentally overdosed with selenium. Due to a 10 to 13 times overdosage of the planned sodium-selenite supplementation (1 mg/body-mass kg) in the drinking water, 15 to 70% of the animals died in the affected groups within 48 hours. Degeneration of the liver, kidneys and myocardium, as well as cerebellar oedema were observed in the dead chickens during the pathological examinations. Selenium content of the liver of dead chickens, calculated for fresh tissues, varied between 3.85 and 4.16 mg/kg. Dyspnoe, watery diarrhoea, weakness and somnolence were observed within a short time when the selenium poisoning was experimentally induced. In the chickens died at different points of time after the selenium overdosage (Table), the following alterations were observed: hepatic degeneration with an increasing severity (vacuolic degeneration, pycnosis of MPS cells, then haemorrhagic hepatic dystrophy, parenchymal atrophy), diffuse tubulo-nephrosis, followed by the necrosis of tubular epithelium, myocardial and skeletal myodegeneration, as well as the damage of the bursa of Fabricius (Figs 1 and 2). Oral LD50 of selenium (in form of sodium-selenite) proved to be 9,7 mg/body-mass kg.