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Animal Veterinary Hospital of Orlando
(407) 855-PETS (407) 855-7387 1320 Oak Ridge Road, Orlando Fl 32809
Written by: Dr. Bruce Bogoslavsky
ASK THE VET
Central Florida Herp Society
Vitamin and mineral supplements are often added to many reptile
diets. However, as with many other products, too much can be as dangerous as
not enough. Preparations should contain both fat and water soluble vitamins
and minerals essential for proper nutrition. Adding any supplement to your
reptiles water may increase the decomposition of the product as well as
decrease the reptiles water consumption. Adding supplements to salads may
effect their palatability. Commercial supplements should be stored in a
cool, dark place and products without expiration dates should be avoided.
Vitamin A deficiency is rare in herbivorous reptiles. Beta carotene, the
precursor of vitamin A, is present in green leafy plants, yellow and orange
vegetables, and fruit. Yolk remaining at the time of hatching will usually
provide adequate vitamin A levels for approximately six months. Vitamin A
is stored in the liver; diets heavy in animal protein can deplete these
stores. Vitamin A deficiency is most commonly observed in young chelonians
fed improper diets. Hypovitaminosis A is the most common cause of
nonspecific, inflammatory, periocular disease in reptiles. The disease is
usually evident within the ocular, genitourinary, and respiratory systems.
Affected animals will exhibit swollen or reddened eyelids and mucous
membranes, nasal discharge, or respiratory distress (dyspnea).
Hyperkeratosis of the skin and mouth parts may also be observed. In
herbivorous reptiles, any vitamin A deficiency should be thoroughly
investigated prior to the use of supplemental vitamin A.
Vitamin A overdosage may occur secondary to excessive supplementation.
This will occur when a single, intramuscular injection, greater than
10,000U/kg is administered. Liver failure, ictrus, jaundice, depression,
and anorexia may all be observed in an animal with a vitamin A overdose.
Tissue sloughing can be observed at the injection site when injectable
vitamin A is used. The exposed tissue will then become susceptible to
bacterial infections. Glucocorticoids will prolong the overdose effect and
therefore should not be used in affected animals. There is no evidence that
vitamin A can be used to stimulate appetite in anorexic reptiles.
Thiamin (Vitamin B1) deficiency is caused by feeding items that contain the
enzyme thiaminase rather than by feeding a thiamin deficient diet.
Thiaminase breaks down the animals stored supply of thiamine. Herbivorous
reptiles may acquire this disease because thiaminase is found in ferns and
ornamental house plants, and by feeding large amounts of frozen vegetables.
Freezing decreases vitamin levels and increases thiaminase activity.
Carnivorous reptiles may acquire a deficiency because thiaminase is found in
fish. Thiamine is necessary for the proper development and function of
nervous tissues. A thiamine deficiency is characterized by nervous
disorders such as: twitching, spasms, blindness, abnormal posture, and an
inability to use specific muscle groups. In snakes, inability to accurately
strike their prey can be observed. Thiamin deficiency can also lead to
dystocia, egg-retention, and other reproductive disorders. These signs may
also be seen with other vitamin deficiencies such as vitamin E or selenium
and they may also be related to other disease processes. Treatment with a
thiamine supplement usually will correct the problem. Adding a small amount
of Brewer's yeast to any frozen food item prior to feeding will also help.
When fish is used as a food item, make sure it is either fresh or
fresh-frozen. Boiling fish prior to its being fed will denature the
thiaminase.
The other B complex vitamins are synthesized by the bacteria and protozoa
with the intestinal tract of normal reptiles. Raw egg whites contain
avidin, which prevents biotin from being processed within the animal. A
deficiency may occur in feeding egg-eating reptiles a diet of exclusively
whole raw eggs. Egg-eating reptiles in nature rarely acquire a biotin
deficiency because most eggs eaten are fertile and embryonic tissue contains
biotin. Occasionally, especially following any antimicrobial therapy, the
normal flora will die off, allowing a deficiency to occur. By using vitamin
B complex supplementation as well as intestinal culture inoculation, the
situation is easily correctable.
Vitamin C (ascorbic acid) is produced within the kidney and
gastrointestinal tract of reptiles. A herbivorous diet, rich in green,
leafy vegetables and citrus fruits is sufficient to prevent this deficiency
from occurring. Affected reptiles will exhibit signs of bruising, bleeding
gums, separation and tearing of the skin, and occasionally diarrhea.
Administration of Vitamin C, is recommended as part of the medical
treatment of infectious stomatitis.
Vitamin D levels will have a direct role on the reptiles calcium level.
In carnivorous reptiles, this will occur when the animals are fed skeletal
muscle and viscera without the bones. In herbivorous reptiles, this will
occur when the animals are fed diets containing oxalates or from low or no
exposure to ultraviolet stimulation either from direct, unfiltered sunlight
or from full-spectrum reptile lights. Vitamin D deficiency will result in a
decrease in the calcium absorption from the large intestine and a subsequent
decrease in the quality of bone growth and development. These changes will
be more obvious in young, rapidly growing reptiles.
Vitamin D overdosage will cause an excess amount of calcium to be absorbed,
resulting in calcium deposits within soft tissues, including the heart.
This may occur secondary to oversupplementation or following ingestion of
rodentacides containing cholecalciferol.
Vitamin E deficiency is usually related to appalling husbandry practice
pertaining to the reptiles diet, such as feeding rancid or spoiled food.
Carnivorous reptiles may develop a deficiency because fish is high in
saturated fats, resulting in this condition. If fish is fed to a reptile,
you need to make sure it is either fresh or fresh-frozen and avoid fatty
fish such as goldfish. Signs of vitamin E deficiency include anorexia,
steatitis, and swollen nodules under the skin. These nodules are actually
abnormal fat deposits, the skin covering these areas is usually discolored
yellow or orange. Occasionally, cardiac muscle abnormalities similar to
"white muscle disease" in mammals, have been diagnosed in reptiles with a
vitamin E deficiency. This myopathy is caused by a decrease in the membrane
integrity of the muscle cells, due to a decrease in the antioxidant effect
of vitamin E.
Vitamin K is synthesized by the normal intestinal flora of reptiles.
Vitamin K deficiency may occur following long-term use of oral antibiotics,
or following consumption of animals poisoned with warfarin, strychnine, or
other coumadin derivatives. Feeding fresh yogurt, Lactobacillus, or fecal
cultures will help replenish the reptiles normal intestinal flora.
When treating sick reptiles, administration of vitamins should be performed
with some caution. Most vitamins work as enzymes with other nutrients and
this process requires fuel to occur. Administering vitamins to anorexic
animals without also administering food, may result in an overdose of the
vitamin. There are varied doses of most vitamins for reptiles. Because of
this, specific doses should be calculated for each patient prior to their
use.
References
1.) Mader, Douglas: Reptile Medicine and Surgery, W.B. Saunders Company,
1996.
2.) Frye, Fredric: Reptile Care; An Atlas of Diseases and Treatments, Volume
1. T.F.H. Publications. New Jersey, 1991.
3.) Frye, Fredric: A Practical Guide for Feeding Captive Reptiles, Krieger
Publishing Company, 1993.
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