Biotin in swine production: A review

Abstract

Biotin, an essential water-soluble vitamin, is a cofactor of a number of enzyme systems responsible for carboxylation and transcarboxylation reactions. These reactions play a major role in the metabolism of carbohydrates and nucleic acids, in the synthesis of fatty acids, proteins and purines, and in the deamination of amino acids. In the past, it was believed that supplemental biotin was not required in swine diets because of its wide distribution in feedstuffs generally used in the formulation of swine diets, and its known synthesis by the pig's intestinal microflora. Interest in biotin nutrition for swine, however, was rekindled when several field reports in the mid-1970s described disease conditions similar to those reported for experimentally induced biotin deficiencies (poor growth in young pigs, low plasma biotin levels, alopecia and pustule formation in the skin and lesions of the hoof and sole of the toes). These conditions were reported to be responsive to biotin supplementation in many cases, but control treatments were usually not included so that definitive conclusions could not be made. Results from properly controlled research are now available, especially from long-term sow studies (three to four parities), which suggest that supplemental biotin may improve one or more of the following: poor litter size, conception rate or weaning to estrus interval, toe lesions and poor haircoat condition. Milk biotin concentration and plasma biotin concentration of sows and piglets were reported to be elevated when supplemental biotin was fed. The amount of biotin in feedstuffs varies from 20 to 2600 parts per billion (p.p.b.), but availability values have not been determined for pigs, although chick bioavailability values suggest that biotin in commonly used grain and protein sources is poorly available. Numerous environmental and nutritional factors may influence the occurrence of a biotin deficiency in swine or alter the level of biotin required in the diet to meet the animal's needs. Using presently available feedstuffs and under modern swine production conditions, a marginal biotin deficiency is possible. There are, however, many unanswered questions and a need for more research to better understand the role of biotin in swine nutrition. Swine producers experiencing poor reproductive performance in their sow herds, associated with excessive loss of hair and severe foot lesions, should evaluate the biotin content of their sow diet and consider supplemental biotin.