ORNITHINE DECARBOXYLASE ACTIVITY IN MUSCLE, LIVER, AND INTESTINAL TISSUE OF TURKEYS DURING A SHORT-TERM FEED WITHDRAWAL AND FOLLOWING REFEEDING

The activity of ornithine decarboxylase (ODC), an enzyme associated wi th cellular grow th and protein synthesis, was examined in breast musc le, li ver, and intestinal tissues of turkeys during a short-term peri od of feed withdrawal (FW) and following refeeding. Turkeys from a ran dombred control line were reared under standard management practices t o 3 wk of age in battery brooders. Feed was then withdrawn from FW bir ds for a 48-h period, after which feed was consumed ad libitum. Contro l birds consumed feed nd libitum throughout the test period. Tissues w ere collected from 12 birds per treatment following 24 and 48 h of FW and at 6, 12, 24, and 48 h following refeeding for later determination of tissue ODC activity. Activity of ODC was greater in tissue from th e small intestine than in liver tissue and both had greater activity t han that exhibited by breast muscle. Short-term FW and refeeding produ ced differential responses in ODC activity of the three tissues examin ed. Feed withdrawal resulted in a reduction of ODC activity in intesti nal tissue, whereas activity was unaffected for liver or breast muscle tissues. Compensatory increases in ODC activity were observed in live r and intestinal tissues; however, the increase was both more rapid an d transitory in small intestine than in liver tissue. The ODC activity in breast muscle was largely unaffected by short-term FW and refeedin g. Patterns of ODC activity in liver during FW and refeeding closely r esembled patterns observed for absolute and relative liver weight. Thu s, the results of the present experiment demonstrate that short-term F W and refeeding influence underlying growth mechanisms of supply organ s, such as hepatic and intestinal tissue, in addition to affecting ove rall growth and muscle development.