Clinical, clinicopathologic, pathologic, and toxicologic alterations associated with gossypol toxicosis in feeder lambs
Morgan, S.; Stair, E.L.; Martin, T.; Edwards, W.C.; Morgan, G.L.
American Journal of Veterinary Research 49(4): 493-499
1988
ISSN/ISBN: 0002-9645 PMID: 3377308 Document Number: 310358
The toxicity of gossypol was studied in 20, 8-week-old feeder lambs that weighed approximately 16 kg. The lambs were allotted to 4 groups (A, B, C, D) and given (orally for 30 days) a daily dosage of gossypol (0, 45, 136, or 409 mg, respectively). Lambs were observed twice daily until they died or were euthized on the day the last dose was given. Clinical, electrocardiographic, clinicopathologic, pathologic, and toxicologic findings were recorded. All lambs given 409 mg of gossypol (group D) died before the end of the 30-day study. In this group, clinical signs included sudden death and/or chronic dyspnea syndromes. One group-B lamb had chronic dyspnea, but did not die. Electrocardiographic abnormalities observed in gossypol-treated lambs included increased amplitude of the T wave and decreased duration of the ST segment. Clinicopathologic alterations in group-D lambs included high serum total lactate dehydrogenase and lactate dehydrogenase liver-specific isoenzyme activities. Serum total creatine kinase activity decreased markedly in lambs of all groups treated with gossypol. Hemoglobinuria was detected in 2 group-D lambs. The average daily weight gain was remarkably consistent in lambs of all groups, except in 1 lamb each of groups D and B. Lambs were necropsied when they died or on day 30 of the study. The heart of gossypol-treated lambs weighed more than did that of untreated (control group A) lambs. In many of the treated lambs, macroscopic lesions included excessive, often red-tinged, pericardial and thoracic fluid volumes, white streaks on the epicardium extending into the myocardium, pale mottled cardiac musculature, generalized icterus, and edematous lungs with wide interlobular septa. Sections of heart, kidneys, liver, spleen, lungs, brain, skeletal muscle (diaphragm and serratus ventralis muscle), bladder, rumen, abomasum, small intestine, and large intestine were stained with hematoxylin and eosin and were examined microscopically. All gossypol-treated lambs had various degrees of cardiomyopathy, characterized by vacuolation and degeneration of myocardial fibers, separation of fibers by edema, influx of lymphoreticular cells, and necrosis of myocardial fibers. Pulmonary and hepatic lesions reflected progressive cardiomyopathy. Liver, kidney, and semimembranosus muscle specimens were obtained immediately after death or euthanasia, and free and bound gossypol concentrations in such tissues were determined. The liver and kidneys of treated lambs had consistently higher free gossypol concentration than did those of control lambs.