Uptake of DL-2-hydroxy-4-methylthio-butanoic acid (DL-HMB) in the broiler liver in vivo.
The methionine source DL-2-hydroxy-4methylthio-butanoic acid (DL-HMB; Alimet feed supplement) is widely used in the poultry industry. The purpose of this study was to determine the capacity of the broiler liver to remove DL-HMB from the circulation. Cannulae were implanted in the carotid artery and hepatic and hepatic portal veins in anesthetized male broilers (3.33 +/- 0.13 kg BW). In Experiment 1, birds (n = 5) were infused with DL-HMB solutions (diluted in saline, pH 7.2 to 7.4) into the hepatic portal vein at rates ranging from 4.4 to 22 mg/min per kg BW, whereas in Experiment 2, birds (n = 6) were infused with DL-HMB at rates ranging from 2.2 to 4.4 mg/min per kg BW. Plasma samples from each vessel were obtained before and after each 10-min DL-HMB infusion period with a 10-min clearance period allowed between each DL-HMB infusion. Regression analysis revealed a highly significant correlation in the amount of DL-HMB entering the liver via afferent vessels (afferent DL-HMB) and DL-HMB removed by the liver (y = 0.86(x) - 173, r2 = 0.98). The slope of this regression indicates that 86% of DL-HMB entering in afferent blood (i.e. from both the hepatic artery and hepatic portal vein) was removed or that the liver apparently metabolized 86% of the DL-HMB that entered the liver. The results indicate that the broiler liver has the capacity to remove DL-HMB from the circulation far in excess of that needed to metabolize DL-HMB that would enter the liver following gastrointestinal absorption in birds fed a conventional poultry diet. In addition, present results implicate the liver as a major site of removal from circulation and further metabolism of DL-HMB in chickens.
Wang
S
S
Department of Poultry Science, University of Arkansas, Fayetteville 72701, USA.
Bottje
W G
WG
Song
Z
Z
Beers
K
K
Vazques-Añon
M
M
Dibner
J J
JJ
D000821:Animal Feed; D000818:Animals; D001794:Blood Pressure; D002339:Carotid Arteries; D002645:Chickens / Q000378:metabolism*; D019587:Dietary Supplements; D006503:Hepatic Veins; D008099:Liver / Q000378:metabolism*; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics*; D011169:Portal Vein; D012044:Regression Analysis
C008391:alpha-hydroxy-gamma-methylmercaptobutyric acid; D008715:Methionine