Biotin concentration is low in typical cereals used in broiler formulas
Cereals are poor sources of biotin, compared with poultry requirements, but they constitute the largest part of their feed (roughly 70%). In contrast, protein sources contain more biotin than cereals, but they play a smaller role in terms of inclusion rate (roughly 25%).
Biotin concentration in typical cereals is rather low: corn and wheat contain about 0.06 and 0.11 mg/kg, respectively. Major protein sources such as soybean and rapeseed meals contain 0.26 and 0.98 mg/kg, respectively.
Lamentably, most natural raw materials are characterized by rather poor biotin bioavailability (less than 50%), which means about half of natural biotin is of no use to the animal. A typical corn and soybean meal formula contains about 0.10 mg/kg biotin, which is clearly deficient compared with requirements set by NRC (1994, USA) at between 0.15 and 0.20 mg/kg. Thus, it is evident that most natural ingredients will fail to satisfy the need for biotin. Supplemental biotin is readily available as d-biotin, but the problem is that it is one of the most expensive vitamins. Thus, premix suppliers tend to be careful how much they include into their products.
In the case of wheat-based diets, the need for biotin supplementation becomes even more pronounced as natural biotin in wheat is virtually unavailable. Thus, when switching from corn- to wheat-based diets, one must re-evaluate the sufficiency of biotin supplementation. It is often suggested to double biotin supplementation when switching from corn to wheat, but this oversimplification does not apply when the main protein source is rapeseed meal, or animal-based ingredients (which are generally rich in biotin) contribute sufficiently to the natural biotin source.