Hypervitaminosis D and Metastatic Calcification in a Colony of Inbred Strain 13 Guinea Pigs, Cavia porcellus

Abstract

A commercial diet fed to a colony of inbred strain 13 guinea pigs for approximately 6 weeks was subsequently recalled for excessive levels of vitamin D. Twenty-one of 62 animals exhibited clinical signs, including anorexia, lethargy, and poor body condition. Nine affected and 4 clinically normal animals were euthanized for further evaluation, including serum chemistry, urinalysis, and gross and/or histopathology. Macroscopic findings included white discoloration in multiple organs in 8 animals, and microscopic evaluation confirmed multiorgan mineralization in tissues from 7 animals. Serum 25-hydroxyvitamin D levels were elevated in 10 animals. Serum inorganic phosphorus and alkaline phosphatase levels were increased in all exposed animals; however, total calcium and ionized calcium levels were not significantly higher in exposed animals than in control strain 13 guinea pigs from a different institution. The data support a diagnosis of hypervitaminosis D with metastatic calcification. Following the diet recall, the remaining guinea pigs increased their food intake and regained body condition. Diagnostic testing of 8 animals euthanized approximately 3 months after returning to a normal diet demonstrated that serum parathyroid hormone remained significantly lower, and ionized calcium and ionized magnesium were significantly higher, in recovered animals compared to controls and exposed animals. These results indicate that diagnostic tests other than serum calcium are necessary for a diagnosis of hypervitaminosis D in guinea pigs.

Hematology and Clinical Chemistry Reference Intervals for Inbred Strain 13/n Guinea Pigs (Cavia Porcellus )

“…8,14,20 Strain 13/N control animals in a dietary hypervitaminosis D study had similar ALP and creatinine values to those in our study, but lower overall total calcium levels. 9 Calcium in our current study increased over time (Figure 4) and may correspond with the development of renal disease in this strain, but we are unable to draw definitive conclusions without measuring other electrolyte levels, including magnesium and phosphorus. 1 Total protein rose rapidly through 150 d without a concurrent increase in albumin, indicating increasing immunoglobulin production in the developing immune system.…”

Dystrophic mineralization of the arterial fibrovascular tissue associated with a vitamin D hypervitaminosis in an 8-year-old female Alpaca (Vicugna pacos)

“…However, increased phosphate levels lead to extra osseous calcium phosphate deposits in various soft tissues, including arteries, in the joints and connective tissues. The result is a progressive and increasing stenosis of the blood vessels that can lead to cardiac and peripheral circulatory disorders [20, 21, 14, 22]. Proper knowledge of the metabolism and the nutritional needs of these animals are therefore necessary in order to prevent deficiency disorders and nutritional problems.…”

“…Overzealous cholecalciferol (Vitamin D) supplementation is known to lead to Vitamin D toxicity, including tissue mineralization and renal failure, not only in animals but also in humans [20, 21]. A correct process of dosing should always be based on history and on actual body weight of the animal and the patient when administered.…”

Biology and Diseases of Guinea Pigs

“…Diets low in Mg, with incorrect Ca:P ratios, or with inadvertent feeding of diets containing extremely high levels of vitamin D have been associated with increased incidence of metastatic calcification (Maynard, et al, 1958, Galloway et al, 1964, Jensen et al, 2013Holcombe et al, 2014). In some situations, additional feedstuff high in vitamin C (e.g., properly cleaned and fresh orange wedges, kale, cabbage) is fed.…”

“…Probable causes of metastatic mineralization include feeding diets with calcium, phosphate, magnesium, and vitamin D imbalances (Sparschu andChristie, 1968 andHolcombe et al, 2014). Mineral deposits are usually calcium phosphates or carbonates combined with other minerals (Jones et al, 1996).…”