Uptake and clearance rates of biotin in pig plasma following biotin injections.

Nine crossbred gilts were surgically fitted with indwelling anterior vena cava cannulae, and randomly assigned to receive intramuscular injections of either 2.2 micrograms biotin/kg body wt, 6.6 micrograms biotin/kg body wt or a sham dose of carrier medium. Plasma biotin concentrations (PBC) were determined from blood samples taken at 39 time points during a 73 h period. There were no time differences (P less than .05) in PBC for the sham injected gilts suggesting no diurnal variation in PBC. The sham injected gilts had an overall mean PBC of 42.5 ng/dl. Following biotin injection, PBC increased and peaked at 4 h (66.7 ng/dl) and 6 h (90.9 ng/dl), respectively for gilts receiving low and high levels of biotin. These increases in PBC resulted in treatment differences (P less than .05) in PBC from 4 h to 10 h post-injection. Biotin uptake and clearance rates were calculated using exponential curves. Uptake rates (% increase PBC/h) were 16.5 and 15.9% and clearance rates (% decrease PBC/h) were 5.7 and 2.8%, respectively, for gilts receiving low and high levels of biotin. Clearance rate, expressed as the amount of biotin cleared per hour, was similar (2 to 3 ng/dl) for both biotin treatments.