Fat Soluble vitamins
– Vitamin A
– Vitamin D
– Vitamin E
– Vitamin K
Prec Cholesterol and ergosterol
Tocoferols antioxidants of PUFA
production of blood clotting factors
Intestinal mucosa converts the precursors to vit A.
• Vitamin A is important for many functions that control cell
growth and differentiation. Without vitamin A abnormal
• Deficiency of this vitamin results in defects in vision, bone
growth, nervous system functions, reproduction, skin
growth, and overall growth.
• Vision defects result from loss of retinal pigment that leads
to night blindness and ultimately total blindness. Early
pigment loss is in retinal rods, structures sensitive to dim
• Vitamin A deficiency in young, growing animals leads to
bone overgrowth, resulting in secondary nerve damage.
Inappropriate deposition of bone causes the bony changes
• Vitamin A deficiency affects reproduction in both sexes. Deficiency
in males causes testicular atrophy and failed sperm production.
Deficiency in females causes heat cycle irregularities, conception
and embryo implantation failures, and inability to maintain
pregnancy and lactation.
• Death of the unborn and spontaneous abortion are common.
Newborns can have many different congenital malformations.
Vitamin A deficiency changes growth and differentiation of
• Skin becomes highly cornified. Respiratory tract epithelium changes
so that an often fatal pneumonia develops.
• Digestive tract epithelium also changes and its functions are
affected. Similar changes develop in epithelium of the urinary tract
and reproductive system of females, and in the eye.
Vitamin D Deficiency
• Vitamin D is most important during growth. It is
essential for normal bone development; its deficiency
• Fortunately, rickets is rare. Cats need less dietary
vitamin D because ultraviolet irradiation of precursors
in skin produces vitamin D. Dogs need dietary vitamin
D because ultraviolet light does not make that
conversion in skin. Puppies raised in sunlight and
receiving no dietary vitamin D develop rickets. Despite
these species differences sunlight is unimportant in
producing vitamin D in the cat as well as the dog; the
dietary amount is important.
• Vitamin E deficiency appears in cats consuming large amounts of
polyunsaturated fatty acids and inadequate amounts of vitamin E.
• Steatitis results and shows signs of inappetance, weight loss, fever
and pain. Inadequate vitamin E absorption or high dietary levels of
polyunsaturated fatty acids with low levels of vitamin E causes
brown bowel syndrome in dogs.
• Deficiency of vitamin E with or without deficiency of selenium
causes many additional problems in other animals. They do not
appear in dogs or cats, except vitamin E deficiency can cause male
sterility in dogs.
• Steatitis (yellow fat disease) in human cats, reptiles and mink fed
on a fat-laden diet, high in polyunsaturated fat and low in
tocopherols. . It is not seen in ruminants.
• Vitamin K deficiency is uncommon. It occurs
most commonly after ingesting a vitamin K
antagonist such as warfarin.
• Deficiency can also develop when digestive
tract disease reduces fat absorption.
• For an unknown reason vitamin K deficiency
sometimes develops in cats fed fish diets
(salmon and tuna).