Blood pyruvate carboxylase activity as a criterion of biotin status in young pigs.

A basal diet containing isolated soybean protein was supplemented with 100 and 500 microgram biotin/kg and another basal diet containing hen-egg albumen was supplemented with 1300 microgram biotin/kg. The five diets were fed to groups of young pigs from four to 12 weeks old. Growth depression or skin or foot lesions characteristic of biotin deficiency were not seen but the undersurfaces of the hooves of pigs given the basal albumen diet were unusually soft. Blood pyruvate carboxylase activity showed a maximum response to dietary biotin at six weeks but by 12 weeks there was no response to supplemental levels greater than 100 microgram/kg. Plasma biotin concentration gave a good indication of biotin intake at all ages.