Vitamin A Deficiency (Hypovitaminosis A in Turtles)

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Hypovitaminosis A is a common problem in pet turtles caused by inadequate Vitamin A intake in the diet. The body requires Vitamin A to form healthy skin, mucous membranes and ducts (small tubes that conduct fluids such as urine, saliva, or bile) within organs such as the kidneys and salivary glands. When Vitamin A is insufficient in the body, squamous metaplasia (an abnormal growth and thickening of cells) occurs, which disrupts the normal function of the skin or organs, most frequently by blocking fluid flow through ducts.

Hypovitaminosis A is most commonly seen in juvenile semi-aquatic turtles, like painted turtles or red eared sliders, or box turtles greater than six months of age. It is seen very rarely in tortoises because they are normally fed a diet that is rich in dark green and yellow vegetables.

Hypovitaminosis A is rarely seen in turtles less than six months of age as the yolk normally contains enough vitamin A to nourish the turtle for several months. As this supply of Vitamin A is depleted, the turtle must eat foods with adequate amounts of vitamin A. Good sources of Vitamin A include dark, leafy greens such as dandelion greens (not treated with lawn chemicals), yellow or orange vegetables such as carrots and other foods containing carotenes. The carotenes are converted in the body to Vitamin A and cannot be overdosed.

Adequate Vitamin A is usually provided in name brand commercial turtle pellets and live whole fish. Deficiencies are most commonly seen when turtles are fed bargain brands or diets high in hamburger/insects. Excessive supplementation with vitamin powders or liver can result in hypervitaminosis A (excess Vitamin A).

What to Watch For

See your veterinarian if you observe any of the following signs:

  • Swollen eye lids
  • Anorexia and weight loss
  • Necrotic stomatitis (mouth infection)
  • Respiratory infections.

    Occasionally turtles may present with hepatic (liver) or renal (kidney) failure, especially if they have been fed high protein diets.

  • Diagnosis

    Diagnosis is based upon husbandry history, clinical signs, physical exam and response to treatment. The symptoms of Vitamin A deficiency are very similar to the symptoms for other diseases so it is important to rule out other causes of the symptoms. It is common for a turtle to have bacterial infections secondary to the Vitamin A deficiency that may require treatment as well. Your veterinarian will probably recommend the following:

  • A thorough history including a precise diet history. Make sure you include all of the foods and the amount actually eaten by the turtle in your diet history. It may be helpful to bring any supplements, such as vitamin or mineral powders, fed to your turtle when you visit your veterinarian.
  • A complete physical exam. This should include an ocular exam, examination of the oral cavity, body mass (weight) determination and abdominal (coelomic) palpation. The ocular exam may require the application of a stain or dye to the surface of the eye to detect corneal ulceration, which is a scratch or wound on the outer surface of the eye.
  • A blood tests. A complete blood cell count (CBC) and serum or plasma chemistry panel may be needed to evaluate the presence of secondary infections or the involvement of body organs other than the eyes (liver or kidney involvement).
  • Biopsy of the abnormal skin. A pathologist studies the sample under a microscope to determine the cause of the abnormal skin. Hypovitaminosis A causes a hyperkeratosis (excess keratin) and squamous metaplasia (abnormal cells) which can frequently be seen on a biopsy. Other causes may include skin cancers, bacterial or fungal infections.
  • Treatment

    The most important treatment for Vitamin A deficiency is changing the turtle’s diet to include adequate amounts of Vitamin A. While this conversion is taking place, your veterinarian is likely to prescribe an oral vitamin supplement. It is important to check the vitamin dose with your veterinarian periodically, because as your turtle begins to eat a more healthy diet, the dose of vitamin powder needs to be decreased to avoid health problems associated with over-supplementation.

    Your veterinarian may want to administer an injection of Vitamin A, but this is usually reserved for severe cases. Vitamin A injections are concentrated, and if excess Vitamin A is given, toxicity occurs. Pancake tortoises seem to be especially sensitive to over supplementation with Vitamin A. Hypervitaminosis A (Vitamin A toxicity) presents similar to Vitamin A deficiency with red, inflamed skin which frequently sloughs.

    Secondary bacterial or fungal infections of the skin, eyelids, mouth or organs may need to be treated. Treatment generally consists of topical (applied to the skin) and or systemic (oral or injected) antibiotics or antifungal preparations. Especially in aquatic turtles, topical preparations may need to be applied frequently as they wash off in the water.

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