Vitamin E is a collective term for tocopherols and tocotrienol derivatives with α-tocopherol activity. Its most significant function in cats is its antioxidant effect, while also enhancing the body's immune system. Currently, eight naturally occurring forms of vitamin E are known, and they are classified into two categories based on the degree of saturation of their molecular branches. The four saturated forms of vitamin E are called α, β, γ, and δ-tocopherols. 
I. Vitamins and Cat Health
Vitamin E acts as an antioxidant in the body, removing oxygen free radicals and lipid peroxidation, and protecting the integrity of cell tissues. Vitamin E helps protect cells from free radical damage. Normal cell metabolism produces free radicals, ultimately leading to aging. External factors, such as exercise, pollution, and sunlight, can also contribute to the production of free radicals. Free radicals accelerate cell death. Vitamin E helps protect cell membranes from free radical damage and strengthens the immune system.
Vitamin E can promote antibody formation and lymphocyte proliferation, enhance cellular immune responses, and reduce the content of immunosuppressants in the blood, thereby enhancing animal immunity and disease resistance. It can also reduce the toxicity of some toxic elements and heavy metals; participate in the synthesis and metabolism of other vitamins and amino acids; regulate muscle metabolism and glycogen balance; interact with selenium to maintain pet health and improve pet stress resistance; in addition, it also has the function of regulating hormone secretion and promoting pet reproductive function.
II. Clinical symptoms of vitamin E deficiency
Vitamin E deficiency leads to excessive oxidation of unsaturated fatty acids in the body, damaging cell membranes and lysosomal membranes and releasing various lysosomal enzymes, such as cathepsins, β-glucuronidase, and β-galactosidase, resulting in degenerative diseases such as organ and tissue degeneration. In young pets, vitamin E deficiency mainly manifests as loss of appetite, slow growth and development, indigestion, diarrhea; muscular dystrophy, motor disorders, lameness, leg paralysis or even paralysis; heart weakness, and subcutaneous edema. In adult pets, it manifests as reproductive disorders, such as decreased ovarian function, abnormal estrous cycles, infertility, abnormal embryonic development, or stillbirth in females; and testicular degeneration, decreased semen quality, and impaired sperm production in males.
III. Causes of Vitamin E Deficiency
Insufficient vitamin E content in feed; excessive unsaturated fatty acids in feed, such as linseed oil and soybean oil, can produce peroxides when they become rancid, promoting the oxidation of vitamin E; increased vitamin E requirements without timely supplementation, such as in growing pets, pregnant pets, pets fed high-fat feed, and pets with a diet lacking sulfur-containing amino acids or selenium, can all increase the pet's need for vitamin E; in addition, various stress factors can also increase the pet's need for vitamin E.
IV. Prevention and Supplementation of Vitamin E Deficiency
Adjusting the diet to include vitamin E-rich feed can help, and supplementing with feed additives containing a mixture of vitamin E and the trace element selenium can also be beneficial. Preventative treatment with vitamin E and organic selenium preparations before mating and during late pregnancy can effectively prevent reproductive problems caused by vitamin E deficiency. Various oilseeds and vegetable oils, such as wheat germ oil, corn oil, peanut oil, sesame oil, legumes, and whole grains, are important sources of vitamin E. Certain grains, nuts, and leafy green vegetables also contain some vitamin E.
V. Vitamin E Requirements and Toxicity in Pet Cats
The minimum requirement for vitamin E in pet cats during their growth and maintenance adulthood is 30 IU per kilogram of dry matter in their diet. Vitamin E is one of the least toxic vitamins, and its absorption rate is relatively low; therefore, vitamin E poisoning in pets is rarely seen in veterinary clinics.
