Effect of Microencapsulation on Absorption Processes in the Pig

A. Piva, P. Anfossi, E. Meola, A. Pietri, A. Panciroli, T. Bertuzzi, A. Formigoni.

Livestock Production Science (1997) 51:53-61

The effects of microencapsualtion with long-chain fatty acids (LCFA) on the absorption and bioavailability of nutrients and drugs was studied in pigs using microencapsulated tryptophan (TRY) and sulfamethazine (SMT). Portal concentrations of tryptophan were monitored in gilts fed a basal diet supplemented with 1.75 and 10.75 g pig-1 day-1 free crystalline or microencapsulated TRY. Sulfamethazine plasma kinetics were studied in gilts orally administered with free-base or microcapsulated drugs (1 g pig -1) at feeding time. Blood samples were collected until 8h and 120 h after feeding in pigs treated with TRY and SMT, respectively. Absorbed fractions of both microcapsualted TRY and SMT were lower than in the free forms by 26 and 32%, respectively, 8h after treatment. Nevertheless, total drug bioavailability measured by the area under the plasma concentration-time curve extrapolated to infinity (AUC 0-∞) was not modified by microcapsulation (970±355 μg ml-1h). These data suggest that microcapsulation delays absorption without affecting the bioavailability of protected compounds.