Biotin deficiencies are not generally a problem; however, the treatment of dogs and cats with antibiotics that decrease the bacterial population of the large intestine will cause an increase in the dietary requirement for biotin. Likewise, including such antagonists in the diet as avidin and rancid fats will inactivate biotin in feeds of biological origin. Carey and Morris (1977) developed biotin deficiency in cats with a semi-purified diet containing dried egg white and sulfathiazole. The deficiency was reversed by administering 250 µg of supplemental biotin by injection every other day. In addition, due to the extreme variation of the biotin content and bioavailability in feedstuffs, pet foods can be unreliable as consistent sources of biotin. Biotin deficiency for dogs is apparently more prevalent than once thought. In a study with small animal practitioners, 60% of clinical signs were cured and a further 31% improved for dogs (119 cases) with hair and skin conditions (Frigg et al., 1989).
Losses of biotin during storage can be considerable. Biotin is readily destroyed by feed rancidity (Pavcek and Shull, 1942). Preparing fresh feeds, storing them only for short periods and keeping them dry and in a well-ventilated storage area will minimize rancidity problems. Also, the diet should be low in feedstuffs containing high levels of pro-oxidants and/or properly protected by an effective antioxidant to avoid destruction of biotin. Biotin is relatively stable in multivitamin premixes, as well as in naturally occurring sources in feeds, and is fairly stable during processing. However, Gadient (1986) reported a 10% to 30% reduction in biotin after three months of storage when the vitamin supplement contained choline and trace minerals. Chlorine has been shown to inactivate biotin. This may be of importance for pets receiving chlorinated drinking water.
