Muscle protein synthesis and degradation in chicks adapted to intermittent feeding: in vitro studies

The effect of intermittent feeding (every 2nd day) on in vitro muscle protein synthesis and degradation was studied in adapted and nonadapted broiler chicks. Protein synthesis, estimated by in vitro incorporation of L-[14C]-tyrosine into muscle protein, was higher in the intermittently fed birds than that in ad libitum fed counterparts or nonadapted birds. In chicks exposed to one 24-hour cycle of food deprivation and restoration, protein synthesis was slightly depressed (nonsignificant). Protein degradation, estimated by free tyrosine released from muscle into the medium, decreased after 24 h of food deprivation and increased after 24 h of food restoration, to the same extent in both adapted and nonadapted birds.