Effect of biotin supplementation of a barley-wheat diet on restoration of healthy feet, legs and skin of biotin deficient sows.

Sixteen sows with induced biotin deficiency were divided into groups of four and fed an egg-white-free barley-wheat based diet without added biotin (control) or supplemented with one of three levels of synthetic d-biotin (100, 200 or 400 micrograms kg-1) for two parities in order to determine the optimal level required to reverse symptoms of the deficiency and to evaluate the relationship among dietary biotin levels, stage of recovery and serum biotin concentrations. Biotin supplementation significantly reduced (P less than 0.05) the incidence of lesions (on the foot pads, above the dew claws and on the skin) and also dry skin, but had no effect (P greater than 0.05) on hoof cracks, hair score or hair density. Time after supplementation had significant effects on reversal of most biotin deficiency symptoms. Interactions between biotin supplementation and time after supplementation suggested that these symptoms were reversed more quickly when higher levels of biotin were fed. Serum biotin concentrations of biotin-supplemented sows were increased with time and exceeded 600 ng litre-1 after 0.5, 1.0 and 1.5 months following biotin supplementation of the basal diet with 400, 200 and 100 micrograms kg-1. In contrast, serum biotin concentrations of the control sows remained low and peaked at 411 ng litre-1 after 2.5 months. The data suggested that supplementation of a barley-wheat diet to provide 147 to 217 micrograms available biotin kg-1 might be adequate to restore healthy feet, legs and skin and concurrently maintain high serum biotin concentrations.