Of the essential vitamins, Vitamin D is the one that has been most frequently involved in pet food recalls. Vitamin D serves many physiological roles, including calcium and phosphorus metabolism, immune system regulation and reproduction in animals.
There are two main active forms of Vitamin D in mammals: ergocalciferol (Vitamin D2) and Cholecalciferol (Vitamin D3). There is also increasing use of 25-hydroxy Vitamin D3 in animal feed. Over supplementation and unintentional cross-contamination have all caused Vitamin D3 excess in pet food.3
Vitamin D is one of the main regulators of calcium balance. Although intake of sufficient Vitamin D is crucial to many normal processes within the body, toxicity through excess intake can result in loss of appetite with subsequent hepatic lipidosis (fatty liver), dehydration, an elevated level of blood calcium, metastatic calcification, kidney failure, and stones in the urinary tract. Humans can develop Hypervitaminosis D (Vitamin D toxicity) by chronic use of excessive Vitamin D supplements.
Most reported cases of Hypervitaminosis D in animals occur after ingestion of commercial pelleted diet with excessive Vitamin D, toxic plants (oat grasses, jessamine, nightshade) or a non-food substance, such as Cholecalciferol rodent bait (Quintox, True Grit Rampage and Ortho Mouse & Rat-B-Gone) or antipsoriasis ointment (Davionex, Dovenex, and Psorcutan).
Diagnosis may be complicated in guinea pigs. Clinical signs are often vague. Although animals can be alert and active, with normal rectal temperature, they all have excessively thin body condition. Some may have excessive thirst and increased urination.1
- Jensen et al. – Hypervitaminosis D in Guinea Pigs with α-Mannosidosis
- David J. Argyle, Malcolm J. Brearley, Michelle M. Turek – Decision Making in Small Animal Oncology
- Safdar N. Khan, Stephen B. Hooser – Common Toxicologic Issues in Small Animals, An Issue of Veterinary Clinics: Small Animal Practice