Developmental changes in acid proteases of the avian proventriculus

Abstract

Developmental changes in acid proteases in the chicken and quail proventriculus were studied. During embryonic stages, the specific acid protease activity of both species showed a peak a few days before hatching and decreased towards the end of the incubation period. The electrophoretic patterns of acid proteases changed considerably at these stages. Within 24 hr after hatching, the activity increased about 30 times that of embryonic stages. Concomitant with this rapid increase, was a shift of electrophoretic patterns to the adult type. This shift occurred even in nonfed, hatched fowls. Electrophoretic patterns and immunochemical studies with the purified chicken and quail pepsinogens revealed that the embryonic and adult proventriculi of both species have stage‐specific and species‐specific pepsinogens.