|Yen, Jong Tseng|
Submitted to: National Hog Farmer
Publication Type: Popular Publication
Publication Acceptance Date: 11/1/2003
Publication Date: 12/1/2003
Citation: YEN, J., KERR, B.J., EASTER, R.A., PARKHURST, A.M. SYNTHETIC AMINO ACID OPTION NOT BEST FOR GESTATING SOWS. NATIONAL HOG FARMER. 2003. v. 48. p. 33-34.
Technical Abstract: Net portal absorption of amino acids (AA) during the 6-h postprandial period was measured in eight gilts (48.5 ± 1.6 kg BW) in a crossover design. The pigs had chronic catheters placed in the portal vein, carotid artery, and ileal vein, and were trained to consume once daily 1.2 kg of a standard grower diet. Blood samples were taken every 30 min for 4 h and then hourly until 6 h after feeding. The first set of blood samples was taken after pigs were fed a meal of the test 16% CP corn-soybean meal diet (16% CP) or the test 12% CP corn-soybean meal diet supplemented with crystalline lysine, threonine, and tryptophan (12% CP + AA) to equal the three AA levels in the 16% CP diet. Pigs were then fed the standard diet for 2 d. Following that, blood samples were again taken after the pigs were fed a meal of the test diet that was not given to them at the first sampling period. Net portal AA absorption was calculated by multiplying porto-arterial plasma AA concentration difference by portal vein plasma flow rate (PVPF), estimated by an indicator-dilution technique employing p-aminohippuric acid as the indicator infused into the ileal vein. Plasma concentrations of lysine and threonine of pigs were affected by the diet x time interaction (P < 0.01). Portal and arterial plasma lysine and threonine concentrations in pigs attained the maximum level by h 1 postprandial when the 12% CP + AA diet was fed, but reached the peak level at h 2.5 postprandial when the 16% CP diet was given. The PVPF of pigs over the 6 postprandial h was less (P < 0.01) when the 12% CP + AA diet than the 16% CP diet was fed. Net portal absorptions of lysine and threonine were also affected (P < 0.05) by time × diet interaction. The peak portal absorption of both lysine and threonine in pigs appeared at h 0.5 postprandial when the 12% CP + AA diet was given, but at h 2.5 postprandial with the feeding of the 16% CP diet. The early appearance of peak portal absorption of lysine and threonine from feeding the 12% CP + AA compared with the 16% CP diet indicates that crystalline lysine and threonine are absorbed more rapidly than protein-bound lysine and threonine in pigs fed once daily.