Ochratoxin a mycotoxicosis in the guinea-pig

Abstract

Ochratoxin A dissolved in dimethylsulphoxide-50% ethanol (1:1, v/v) was administered to male and female guinea-pigs in doses of 5·6, 7·5, 10, 13·3 and 20mg/kg/day by gastric intubation for 14 days. Clinical, clinico-pathological, gross and histopathological observations were made. The 14-day LD 50 was 9·1 mg/kg for males and 8·1 mg/kg for females. The dose of 5·6 mg/kg was essentially a no-effect dose. Loss of body weight was the most consistent clinical change observed and was roughly proportional to the dose of the mycotoxin. Alterations in clinico-pathological values included increased total plasma protein, decreased serum potassium and chloride, proteinuria and increased serum and urinary lactic-dehydrogenase activities. Gross lesions were not striking, but included pale discoloration of the kidneys, fluid contents and petechiae in the caecum, gastric atony, and congested and enlarged lymph nodes. Major histological changes occurred in the kidneys, lymphoid tissues and gastro-intestinal tract. Renal alterations were degeneration and necrosis of the tubular epithelium, involving both straight and convoluted portions of the proximal tubules, together with tubular dilation and hyaline-cast formation. Congestion, necrosis and oedema involved lymphoid tissues such as lymph nodes, spleen, thymus and the submucosal lymphoid tissue of the gut. Gastro-intestinal lesions included mucosal hyperaemia, necrosis of mononuclear cells of the lamina propria, and caecal and gastric mucosal ulceration.