Bioassay Procedure for the Diagnosis of Aflatoxicosis in a Pig Farm in Nsukka, South East Nigeria

The owner of an intensively reared pig farm in Nsukka, South-East Nigeria reported the deaths (within one week) of 90 piglets (2-3 months of age) out of 150 piglets on the farm. The piglets were being fed home-compounded ration composed of spent grain (which appeared moldy) and other locally sourced materials. Clinical signs observed in affected piglets include sudden loss of appetite, diarrhea and distress grunting sound prior to death. Symptomatic treatment of the piglets which included the use of antibiotics (tetracycline, LA) did not appear to have ameliorated the condition. At necropsy carcasses were generally in fair to good body condition; with subcutaneous hemorrhages, mainly under the skin of head and neck regions. Lungs were congested and edematous, with froth along the tracheal and bronchial airways. The liver and spleen were moderately congested, while the mucosae of the gastrointestinal tract (which was free of ingesta) appeared mildly hyperaemic. No pathogenic bacterium was isolated from the heart blood and spleen. Histologic section of the liver showed centrilobular hepatocytes vacoulation and necrosis with hypertrophy of Kupffer cells that were in erythrophagocytosis. There was moderate fibrinous exudation into the interlobular septae. Spleen section showed severe erythrophagocytosis, but mild haemosiderosis. White pulp was either reactive or depopulated. Lungs were severely haemorrhagic with bronchitis and bronchiolitis. A tentative diagnosis of mycotoxicosis was made and the spent grain-compounded ration was fed to different groups of ducklings, with/without arginine and lysine supplementation. On the bases of clinical signs and mortality pattern; gross and histologic changes in the liver of the ducklings, a definitive diagnosis of aflatoxicosis was made. This paper emphasizes the experimental feeding of suspected feeds/feed ingredient to ducklings as a reliable diagnostic model for aflatoxicosis.