VISCERAL OXYGEN-CONSUMPTION DURING CHRONIC FEED RESTRICTION AND REALIMENTATION IN SHEEP

The objectives of this study were twofold: first, to estimate the time required to reach equilibrium in splanchnic tissue oxygen (O-2) consu mption rates after a feed restriction that maintained BW; and second, to estimate the time following a subsequent realimentation required to reach equilibrium. Catheters were placed in a cranial mesenteric vein , the portal vein, a branch of the hepatic vein, and the abdominal aor ta of six wethers. Wethers were allowed to eat ad libitum 2 h/d. At 49 .9 +/- 2.7 kg two wethers were assigned to the high group, which conti nued to receive the 2 h/d ad libitum meal. Four wethers were assigned to the low group for 80 d and were restricted to 70% of the average me al each consumed during the week before restriction. Hepatic and porta l-drained viscera (PDV) O-2 consumption rates were determined the day before restriction (day 0) and on d 10, 24, 38, 52, 66, and 80 of rest riction. After d 80 of restriction, wethers assigned to the low group were fed the 2 h/d ad libitum meal, and hepatic and PDV O-2 consumptio n rates were determined on d 7, 14, 28, and 42 of realimentation. At 8 0 d of restriction, PDV and hepatic O-2 consumptions were 60 and 65%, respectively, of the d-0 rate. Hepatic tissue required 21 d and PDV re quired 29 d to be within 5% of the new steady-state O-2 consumption ra tes after restriction.