Vitamin H or B7, commonly known as biotin, is an essential vitamin that is a water-soluble B vitamin.
Like all B vitamins, it is water soluble, meaning the body does not store it. However, bacteria in the intestine can make biotin. It is also available in small amounts in a number of foods. Biotin is needed for normal function of the thyroid and adrenal glands, the reproductive tract and the nervous system. Biotin is active in skin formation and maintenance, and a deficiency causes abnormal keratinization and cornification of the epidermis, leading to low tensile strength and skin lacerations.
Biotin Deficiency in Chickens
The most common clinical signs of biotin deficiency in chickens include one or more of the following:
- Dry scaly, flaky skin along the legs and top portions of the feet.
- Their foot pads along the bottoms of the feet will become roughened, callused, and may develop deep fissures which will may start to bleed.
- Lesions may develop along the corners of the bird's mouth, and slowly spreads to the whole area around the beak.
- Disturbed and broken feathers
- Sticky eyelids, often unable to open
- Young, growing chicks may develop leg deformities, consisting of perosis, crooked legs, and enlargement and twisting of the hock joint.
- Impaired muscular coordination (Young, growing chicks)
- Beak deformities, such as scissors beak and parrot beak (Young, growing chicks).
- Delayed wound healing
Chickens with biotin deficiency are at an increased risk of developing secondary bacterial infections anywhere where their skin is exposed---such as their feet (bumblefoot) and bare patches without feathers (breast blister). There has also been an association made between biotin deficiency and fatty liver syndrome in laying hens.
Biotin Food Sources
Biotin is widely distributed in many different types of foods. However rich sources include brewer's yeast, cooked eggs (raw egg whites contain a protein called avidin, which is known to interfere with absorption of biotin), milk, vegetables, and oilseeds. Poor sources of biotin include corn, wheat, other cereals, fishmeal, and any canned products.
Biotin Nutritional Requirements
Biotin requirements in chickens may differ slightly depending on genetics. Bioavailability of biotin is poor in most commercial feed products for chickens, since many are corn, soybean meal, or wheat-based, which are ingredients which don't naturally contain much biotin.
| Age/Life Stage | mg/kg |
|---|
| Newly Hatched Chicks (0 - 10 wks) | 0.15-0.2 |
| Young & Growing (10 - 20 wks) | 0.1-0.15 |
| Laying hens (Actively laying eggs) | 0.1-0.15 |
| Breeders (20 wks & older)* | 0.25-0.4 |
| Broiler/'Meat' Breed Chicks (0-18 wks) | 0.2-0.4 |
| Broiler/'Meat' Breeds* (19 wks & older) | 0.25-0.4 |
Risk of Over Supplementing
Animals have been reported to tolerate dietary biotin levels 4 to 10 times nutritional requirements. Toxicity cases are rare.
