Experimental aflatoxin B1 toxicosis in young rabbits - a clinical and patho-anatomical study

A feeding trial was conducted to assess the clinical, gross and histopathological alterations in various organs of New Zealand White rabbits fed an aflatoxin B1 (AFB1) contaminated diet. Aflatoxin extract was included in a toxin-free diet to provide the desired level of 0.5 ppm/kg of feed for ad libitum consumption by 16 young rabbits for a period of 50 days. Clinical signs of toxicosis were noticed from the 20th day onwards and were initially characterized by dullness, lethargy, reduced feed and water intake, hyperirritability, dyspnoea, oliguria and dehydration, which was followed by paralysis of the hind limbs, reduced heart rate and jaundice at the terminal stage of toxicosis. A decrease in body weight was observed in the treatment group. The carcasses of the rabbits in the toxin-fed group appeared emaciated and anaemic with subcutaneous oedema and gelatinization of fat. The liver and kidneys were the most affected organs followed by the stomach, intestines, lungs, heart, spleen, gonads and brain. Grossly, congestion and focal haemorrhages were observed in the affected organs in the initial stages. At the terminal stage of toxicosis, the liver was enlarged, icteric with greyish-white necrotic foci on all the lobes; nephrosis, catarrhal enteritis, pneumonia and mild testicular atrophy were also observed. Histopathology revealed vascular congestion, leucocytic infiltration and degenerative change in the affected organs during the initial stage of toxicosis. At its terminal stage, coagulative necrosis, perivascular and periductal fibrocellular reactions along with mononuclear-cellular infiltration and distortion of the hepatic chords were observed in the liver. Gastrointestinal ulcerations, hyalinization of the tubular epithelium and a widening of the glomerular capsules (Bowman’s capsules) were also observed in the kidneys. The seminiferous tubules showed degeneration/denudation of the epithelium and a reduction in the number of mature spermatids. The study highlighted the toxic effects of a subacute dietary exposure of rabbits to AFB1.