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|Title:||The Effects of Carbadox, a Synthetic Antimicrobial Agent, on Bile Acid Metabolism in The Domestic Pig|
|Author(s):||Tracy, John Driver|
|Department / Program:||Animal Science|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Health Sciences, Medicine and Surgery|
|Abstract:||In order to study the bile acids of the young pig as they go through enterohepatic circulation without altering bile flow from the gall bladder, a surgical technique was developed to place indwelling catheters into the hepatic portal vein (HP) which allowed multiple sampling of the blood and did not affect the performance of the pigs. An indwelling catheter was also placed in the anterior vena cava vein (VC).
Radiolabeled chenodeoxycholic acid (CDC) was infused into the HP and fluctuations of the plasma radioactivities of CDC and its metabolites were monitored in young unrestrained pigs. The fluctuation patterns were similar to previously reported bile flow patterns measured using bile duct catheters. There was a significant difference in the plasma radioactivity between the morning and evening meals from both VC (P < 0.003) and HP (P < 0.0001) plasma samples. There was a correlation of 0.74 between the 2 sources of plasma.
To study the effects of an antimicrobial feed additive on bile acid metabolism carbadox (CX) was added to a 19.5% corn-soybean ration and fed to young pigs. The data showed that CX at 58 ppm affected (P < 0.01) apparent clearance of CDC from the HP blood. The plasma concentrations of the bile acids (as measured by radioactivity) were higher (P < 0.0001) in the animals fed CX. Plasma fluctuations of the bile acids in response to meals showed that the plasma bile acid concentrations (as measured by radioactivity) following feeding at 1600 hours were greater (P < 0.0001) than plasma concentrations following feeding at 0800 hours. The rate of excretion of the bile acids in the feces was increased (P < 0.0001) and bilogical halflife of CDC decreased (P < 0.0001) to 5.7 in the CX-fed pigs from 6.4 days in the controls.
There was an unexplained increase (P < 0.10) in water intake and urine output by the CX-fed animals.
It was found that the feeding of CX did not significantly affect the activity of cholesterol 7(alpha)-hydroxylase (CH-7(alpha)), the rate-limiting enzyme for bile acid synthesis. There was less (P < 0.10) lithocholic acid in the bile of CX-fed pigs. There appeared to be less hyodeoxycholic acid (HDC) in the bile of the CX-fed animals. (Abstract shortened with permission of author.)
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.
|Date Available in IDEALS:||2014-12-15|