Vitamin A for Turtles
Turtles are a popular pet, and they can be very rewarding to care for. You should know, however, that turtles require special care. They need a certain amount of vitamin A in their diet each day; otherwise they may develop health problems.
Vitamin A is an essential nutrient that helps your turtle’s eyesight and immune system function properly. It also helps them grow strong shells and bones. In fact, vitamin A is so important to your turtle’s health that if it doesn’t get enough vitamin A in its diet, it can become blind or die from severe infections!
To ensure your turtle has enough vitamin A in its diet you should feed it leafy greens such as dandelion greens or butter lettuce every day. You should also give it foods that are high in beta carotene (such as carrots) as often as possible—but remember not to feed these foods before bedtime because beta carotene makes turtles sleepy!
Vitamin A For Turtles
Vitamin A is one of the fat-soluble vitamins. It is an antioxidant, helps in the growth and repair of tissues, and is important for proper functioning of the eyes, skin, mucous membranes, and ducts (small tubes which carry fluid from one tissue to another).
A condition termed “squamous metaplasia” occurs in vitamin A deficiency, which results in a thickening of the lining of ducts, often blocking the flow of fluid through the ducts. This is most common in the tear ducts, and ducts in the pancreas and kidneys. A deficiency in vitamin A, called “hypovitaminosis A,” is common in aquatic and hatchling turtles fed inadequate diets.
What nutritional problems are associated with hypovitaminosis A in turtles?
Vitamin A is present in high quantities in green leafy vegetables (especially dandelion greens), yellow and orange vegetables such as carrots and yellow squash, whole fish, and liver. Turtles fed iceberg lettuce, an all meat diet, or a poor quality commercial diet are prone to develop a vitamin A deficiency, since these foods have very low levels of this vitamin. Hatchling turtles fed high protein diets are also at risk of developing a deficiency.
What are the signs of hypovitaminosis A in turtles?
Signs of hypovitaminosis A include:
- Swollen eyelids
- Loss of appetite and weight
- Raw skin with secondary bacterial infections
- Nasal discharge (runny nose)
- Necrotic stomatitis
- Abnormal development of the eyes in embryos
The most characteristic sign of vitamin A deficiency in turtles is swollen eyelids. Often, the swelling is so severe, the eyes cannot be opened. This swelling is also a common sign of bacterial infection of the eyes or respiratory tract, or a result of eye irritation from dirty or dusty shavings. Therefore, a definitive diagnosis must be made before any treatment is started.
In severe cases, the pancreas, liver, and kidneys could also be affected.
How is hypovitaminosis A in turtles diagnosed?
The history of the nutrition and husbandry of the turtle is very important in making a diagnosis of hypovitaminosis A. The veterinarian will need to know what the turtle has been and is presently being fed, including any supplements.
The species of turtle, signs of disease, and physical examination will also provide valuable information. Other causes of the signs, such as infections, need to be ruled out. The severity of the tissue injury will be evaluated such as the presence of corneal ulcers, pneumonia, or secondary infections. Laboratory tests such as a chemistry panel and complete blood count (CBC) will help determine the health of the internal organs such as liver and kidneys. A bacterial culture and/or biopsy of lesions may also be performed.
How is hypovitaminosis A treated?
The key to treatment is providing a nutritionally balanced diet, developed specifically for the species of turtle, taking into account whether it is a carnivore or herbivore. Vitamin A supplements will usually be given orally (the preferred method) or by injection (if the condition is severe) until proper levels in the body are restored. Turtles with a vitamin A deficiency are often deficient in other nutrients as well, such as vitamin E and zinc, so these nutritional imbalances need to be corrected as well. Care must be taken to not oversupplement, since vitamin A toxicities can occur. Follow your veterinarian’s directions carefully. If feeding commercial diets, such as trout food, it should be fresh, and of high quality.Foods High in Vitamin A
- Broccoli leaves and flowerets
- Collard greens
- Dandelion greens (beware of lawn treatments)
- Mustard greens
- Sweet potatoes
- Turnip greens
- Yellow squash
- Whole fish
Foods Very Low in Vitamin A
- Summer squash
- White potatoes
Secondary bacterial or fungal infections will be treated with antibiotics orally, by injection, or applied to the skin or eyes.
Any poor husbandry conditions will need to be addressed such as type of shavings or inadequate sanitation.
The earlier a case of hypovitaminosis A is diagnosed, the faster the response to treatment and the less likelihood of permanent damage. If your turtle is showing signs of illness, consult your veterinarian.
vitamin a for reptiles
CONSULT THE EXPERT
Thomas H. Boyer, DVM,
DABVP (Reptile & Amphibian)
Pet Hospital of Penasquitos
San Diego, California.
Vitamin A is an essential hormone
that activates genes for maturation of immature epidermal
cells (ie, keratinocytes). Without vitamin
A, cells undergo hyperkeratosis (ie, an
abnormal thickening of the stratum
corneum, associated with excess keratin)
and squamous metaplasia (ie, transformation of cuboidal, columnar, or ciliated
glandular or mucosal epithelium into
keratinizing stratified squamous epithelium), particularly in the respiratory,
ocular, endocrine, GI, and genitourinary
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CONSULT THE EXPERT h EXOTIC ANIMAL MEDICINE h PEER REVIEWED
Background & Pathophysiology
Vitamin A deficiency is common in all captive
insectivorous reptiles, including leopard
geckos (Eublepharis macularius), chameleons
(most commonly panther [Furcifer pardalis],
veiled [Chamaeleo calyptratus], and Jackson’s
[Trioceros jacksonii]), and anoles. It occurs less
often in wild reptiles, likely because of their
varied diet, which typically includes other
reptiles, mammals, birds, and invertebrates.
Vitamin A deficiency is thought to result from
dietary deficiency; it is unknown if insectivorous lizards can synthesize vitamin A from
carotenoids in their diet. Dietary history and
multivitamin review may disclose a lack of
vitamin A in the patient’s diet2; for example,
the patient may not be fed multivitamins that
contain vitamin A or may be fed insects that
do not receive gut-loading diets or other foods
containing vitamin A. Feeder insects are generally deficient in vitamin A and often receive
diets deficient in vitamin A. In addition,
many food manufacturers omit vitamin A and
substitute β-carotene in reptile multivitamins because of misinformation that vitamin
A is toxic to insectivores.1
Many patients with vitamin A deficiency have
long-term ocular disease that is not responsive to multiple antibiotics.2 Both lacrimal
and salivary glands are commonly affected,
and patients may have blepharitis, blepharospasm (Figure 1), and cheilitis. These patients
typically are anorexic and have difficulty
shedding (ie, dysecdysis). Leopard geckos
may be presented with mucoid-to-solid cellular debris under the eyelids (Figures 2 and 3),
ulcerative keratitis, and/or abscessation of
periocular glands. Chameleons may have
mucoid buildup in the eye, thickened conjunctiva, difficulty capturing prey with the
tongue (possibly from dysfunction of sticky
mucus glands in the tongue tip), and dull coloration (Figure 4, page 18), which can be difficult to identify on examination. Chronic
cases may result in blindness.
Herbivores (eg, tortoises, green iguanas
[Iguana iguana]) and omnivores (eg, bearded
dragons [Pogona vitticeps]), along with carnivorous lizards and snakes that eat the
entire body of an animal, generally are not
affected by vitamin A deficiency. Omnivorous
Emydidae turtles (eg, box turtles [Terrapene
d FIGURE 1 Healthy panther chameleon (Furcifer pardalis; A) with clear rounded eyelids as compared with a panther
chameleon with vitamin A deficiency (B). Dull coloration, cheilitis, blepharedema, squinting, mucoid ocular buildup,
and dysecdysis are visible over the head and eyelid openings.
August 2018 cliniciansbrief.com 17
d FIGURE 2 Vitamin A deficiency in a leopard gecko (Eublepharis macularius). Solid cellular debris in the right (A) and left
(B) eyes, cheilitis, and dysecdysis can be seen.
d FIGURE 3 Leopard gecko from Figure 2 with solid cellular debris in both eyes due to vitamin A deficiency shortly after
debris removal (A), with enhanced view of removed cellular debris (B)
spp]) and red-eared sliders (Trachemys scripta
elegans) can develop vitamin A deficiency.
Diagnosis of vitamin A deficiency is based on
dietary history and clinical signs. Because
most vitamin A is stored in the liver and circulating levels do not fall until liver reserves are
exhausted, circulating levels may not be an
accurate indicator of overall vitamin A status.
Normal values for liver or circulating levels
of vitamin A or retinol are often unknown.
Required blood and liver biopsy sample sizes
may be greater than can be obtained safely in
small patients, and incorrect sample handling
and assay techniques can alter values.
Differential diagnoses for ocular and gingival
disease may have numerous causes, including
infectious (eg, bacterial, fungal, parasitic,
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viral), neoplastic, metabolic (eg, calcium deficiency [exposure gingivitis], uric acid deposits [conjunctivitis, retinal detachment,
blepharospasm]), traumatic, and environmental (eg, from substrate, ultraviolet light,
Fluorescein staining may reveal corneal ulcers.
Corneal cytology may disclose secondary bacterial, fungal, parasitic, or neoplastic disease.
A vitamin A supplement should be added to
the patient’s diet. All vitamin A doses are
empiric and range from 5000-66666 IU vitamin A palmitate per kg IM, SC, or PO every
1 to 2 weeks for 2 treatments.1,3 Injectable
vitamin A has been associated with hypervitaminosis A; oral supplementation is preferred. Fat-soluble vitamin A is much less
toxic than water-soluble vitamin A.
Broad-spectrum ophthalmic antibiotic ointments or antibiotic drops should be administered to lubricate and prevent secondary
bacterial infection of the cornea, if compromised. In leopard geckos, solid cellular debris
should be moisturized under the eyelids with
saline and removed with blunt probes, hemostats, or fine forceps. The patient should be
checked for ulcers using fluorescein staining,
and eyes should be flushed copiously with
saline. Similarly, eyes of chameleons should
be flushed with sterile saline to remove thickened mucus and accumulated cellular debris
secondary to xerophthalmia. Retained sheds
around the eyes and feet and retained hemipenal casts should be removed with the
patient under anesthesia.
If the patient has not eaten recently, nutritional support should be provided via fluid
therapy and oral caloric supplementation.
If the patient is eating, the quality of its diet
should be improved. Owners should be
instructed to gut load feeder insects with a
diet containing vitamin A, at least 8% calcium, multivitamins, trace minerals, proteins,
carbohydrates, and fat; to dust all insects with
calcium before each patient feeding; and to
feed multivitamins containing vitamin A—
rather than calcium—twice a month.
d FIGURE 4 Panther chameleon with vitamin A deficiency and blepharospasm on presentation (A) and 2 weeks after a
single injection of vitamin A palmitate (B). The eye is markedly improved, but some blepharedema remains.
August 2018 cliniciansbrief.com 19
Wild insectivorous reptiles eat hundreds of
invertebrates (eg, insects, arachnids, mollusks, crustaceans), other lizards, mammals,
and birds, so pet lizards should be fed as wide
a variety of insects as possible; diet should
not be restricted to crickets, mealworms,
super or king mealworms, waxworms, and/or
Dubia roaches. Reptile specialty stores and
online vendors sell a wide variety of insects,
including other cricket species (eg, black,
field, banded), silkworms, black soldier fly
larvae (sold as Phoenix worms), tobacco or
tomato horn worms (sphinx or hawk moth
larvae [sold as goliath worms or green
giants]), butterworms, bean beetles, fruit
flies, springtails, and wood lice, as well as
wild-caught seasonally available insects (eg,
moths, cicadas, flies, grasshoppers, katydids,
bees [with stingers removed], cockroaches,
crustaceans [eg, pill bugs, roly-poly bugs],
mollusks [eg, snails, slugs]). Fireflies contain
highly toxic lucibufagins and should never
be fed to pet lizards.4 Some insectivorous
reptiles will also eat neonatal mice, which
are rich in vitamin A.
Patients should be re-evaluated every 1 to 2
weeks until they are eating readily and appear
healthy. Body weight should be monitored to
determine if nutritional supplementation is
indicated, and dietary recommendations
should be reviewed with the owners at each
appointment to ensure they understand and
have implemented the changes.
In one study of cricket gut-loading diets, 3 of
4 diets did not improve the crickets’ calcium
content because they were not calcium
enriched.5 Feeder insects should be fed a
gut-loading diet high in calcium. Calciumfortified, high-moisture cricket wafers or
high-moisture foods (eg, gel water cubes) are
ineffective at increasing calcium or vitamin A
content and are not recommended, even as a
water source.6 Studies have shown that cubes
decrease the effectiveness of gut-loading diets.
Larvae will take water from damp paper towels, and other insects will drink from waterfilled cotton balls in a bottle or syringe cap.
Multivitamins should be discarded if no vitamin A is present, the supplement has expired,
or the supplement is more than a year old.
Prognosis is poorer when clinical signs are
more advanced or have been present for 6
months or longer. Patients with concurrent
disease (eg, hepatic lipidosis, nutritional secondary hyperparathyroidism) also have a
poor prognosis. If vitamin A deficiency is
diagnosed early and treated appropriately,
most patients will make a full recovery.
Patients with long-term vitamin A deficiency
may be blind, and patients with severe cases
may have corneal fibrosis similar to chronic
canine keratoconjunctivitis (Figure 5).
Patients with a history of anorexia lasting several months may have hepatic lipidosis and
may be susceptible to refeeding syndrome. d FIGURE 5 Corneal scarring in a leopard gecko as a
sequela to chronic untreated vitamin A deficiency
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Vitamin A deficiency in insectivorous reptiles
is common and can result in severe epithelial
disease, especially involving the eyes. Close
attention to diet can prevent and diagnose
this deficiency. Insectivores must be fed a varied diet, insects should be dusted with multivitamins containing vitamin A twice
monthly, and, most importantly, feeder
insects must be fed a balanced diet that contains vitamin A and 8% calcium. Clinicians
should discuss these requirements in detail
with all owners of insectivorous reptiles and