Effects of high-copper feeding on portal ammonia absorption and on oxygen consumption by portal vein-drained organs and by the whole animal in growing pigs
1993
Yen, J.T. | Nienaber, J.A.
Growing gilts that had catheters inserted into the portal vein, ileal vein, and carotid artery and that were trained to consume 1.2 kg of a 16% CP corn-soybean meal basal diet once daily were used. In Trial 1, hourly simultaneous measurements of the O2 consumption by portal vein-drained organs (PVDO) and by the whole animal during the 24- to 30-h postprandial period were conducted in eight pigs (33.8 +/- .6 kg). After initial measurements, four pigs continued to receive the basal diet and four pigs were fed a basal diet + 250 ppm of Cu. Following a 7-d acclimation period, the second series of measurements were made. In pigs fed the diet supplemented with Cu, the PVDO and whole-animal O2 consumptions and the fraction of whole-animal O2 consumption used by PVDO were not different (P > .05) between the initial and second series. In Trial 2, seven gilts (38.5 +/- .9 kg) were used for measurements of net portal NH3 absorption and the O2 consumption by PVDO and by the whole animal during the 0- to 6-h postprandial period. The second series of measurements were made 7 d after four pigs were fed the diet supplemented with Cu. For pigs fed the diet supplemented with Cu, during the second series of measurements, the net portal NH3 absorption was lowered (P < .05). No differences (P > .05) in PVDO and whole-animal O2 consumptions and the fraction of whole-animal O2 consumption used by PVDO were found between the initial and second series. These results indicate that mechanisms other than reduced oxidative demand by PVDO may be responsible for the growth-stimulating effect of high dietary Cu on pigs.
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