Biotin or vitamin B7 or H is a water-soluble member of the B complex vitamins.
Some foods that contain it include liver and other meats, egg yolk, yeast, seeds and nuts, salmon, dairy, sweet potatoes, avocados, and cauliflower.
Biotin is essential in cats. It plays various important roles that including the following:
- According to Dms.com, it is “an essential coenzyme in carbohydrate, fat and protein metabolism. It is involved in the conversion of carbohydrate to protein and vice versa, as well as the conversion of protein and carbohydrate to fat.”
- It plays a part in ensuring the levels of blood sugar are normal through protein and fat metabolism in cases where there is low carbohydrate consumption.
- Furthermore, as pets.thenest.com notes, it “supports the thyroid and adrenal glands and the reproductive and nervous systems.”
- Finally, it is essential for a healthy skin, hair, nails and skin coat.
Is there a need for biotin for cats supplementation?
Biotin should not be supplemented in a cat’s diet unless the specific food has anti-vitamins or antimicrobials. Any diet that has been labeled “complete and balanced” has enough of the vitamin H that this pet requires.
On required amounts, NRC (2006) recommends that diets have 75µg of B7 per kilogram of such foods for all cat classes while AAFCO puts the amount at 70 µg/kg of cat food.
However, it is possible to get several supplements including Bio Coat Concentrated Biotin Supplement and Nickers International Bio-Coat Supplement intended to help conditions such as a dull coat, dry skin, skin itchiness, too much fur shedding, among other roles.
Deficiencies are not common unless biotin is depleted by prolonged use of antibodies during antibody therapies or if these pets are having poor diets including too much egg whites.
Deficiency symptoms include skin problem characterized by a shabby look, lesions that will first be noticed on the face then appear on legs and the rest of the body, among others.
For instance, deficiency has been reported in kittens that are fed on about 18.5-32% raw eggs whites since they contain a protein known as avidin which hinders the normal absorption of this vitamin. 
Some of the deficiency symptoms such kittens showed include skin problems such as dried secretions noted on mouth angles and around eyes and the nose, scaly dermatitis, especially on the nasomaxilla-mandibular region. Also, there was alopecia on the face, bloody diarrhea, loss of appetite, and weight loss.
No studies have been conducted on cats. However, huge amounts of vitamin B7 at 5mg per 100 g rat has been linked with estrus cycle irregularities and no effects for up to 10,000 times the required amounts.
Similarly, there has been no deleterious effects on swine and poultry for levels that are 4-10 times what NRC recommends.
This animal studies and the fact that this is a water-soluble vitamin should be used to draw a conclusion that an over-supplementation may not have serious health issues. It will be excreted via the kidney and out through urine.