Effect of oral administration of excessive iron in adult ponies.
OBJECTIVE
To evaluate the potential of excess dietary iron to cause hepatic lesions similar to those described in horses with suspected iron toxicosis or hemochromatosis.


METHODS
Prospective study.


METHODS
6 adult male ponies.


METHODS
4 ponies received 50 mg of iron/kg (22.7 mg/lb) of body weight each day by oral administration of ferrous sulfate, which contained 20% elemental iron; 2 ponies received only the carrier (applesauce). Complete blood counts, serum biochemical analyses, and hepatic tissue biopsies were performed, and serum iron concentrations were measured. Blood and tissue samples were obtained at days 0 and 2, and at the end of weeks 1, 3, 6, and 8 after administration of iron was initiated. Treatment was discontinued after 8 weeks, and hepatic iron concentrations were measured at 28 weeks.


RESULTS
Hepatic iron concentrations, serum iron concentrations, percentage saturation of transferrin, and serum ferritin concentrations were increased, compared with baseline and control concentrations, by week 8. Adverse clinical signs or histologic lesions in the liver were not detected in any ponies. At 28 weeks, hepatic iron concentrations had decreased.


CONCLUSIONS
Histologic lesions were not seen in the hepatic biopsy specimens obtained from the ponies treated with ferrous sulfate. It was concluded that it would be unlikely for iron toxicosis to develop in adult ponies or horses during a period of < 8 weeks when food or water contained increased amounts of iron. It is suspected that previous reports of hepatopathies in animals with hemosiderin accumulation may represent a primary hepatopathy with secondary hemosiderin accumulation, especially if the only source of iron is via oral consumption.
Pearson
E G
EG
Department of Clinical Sciences, College of Veterinary Medicne, Oregon State University, Corvallis 97331, USA.
Andreasen
C B
CB
D000284:Administration, Oral; D000818:Animals; D001707:Biopsy, Needle / Q000662:veterinary; D001772:Blood Cell Count / Q000662:veterinary; D056486:Chemical and Drug Induced Liver Injury; D005243:Feces / Q000737:chemistry / Q000469:parasitology; D005296:Ferrous Compounds / Q000008:administration & dosage / Q000009:adverse effects / Q000378:metabolism; D006485:Hemosiderin / Q000378:metabolism; D006734:Horse Diseases / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D006736:Horses; D019266:Iron, Dietary / Q000008:administration & dosage / Q000009:adverse effects* / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008107:Liver Diseases / Q000473:pathology / Q000662:veterinary*; D008297:Male; D009780:Occult Blood; D011446:Prospective Studies
D005296:Ferrous Compounds; D019266:Iron, Dietary; C020748:ferrous sulfate; D006485:Hemosiderin