Tracy J D, Jensen A H
University of Illinois, Urbana 61801.
J Anim Sci. 1987 Oct;65(4):1013-8. doi: 10.2527/jas1987.6541013x.
Two experiments were conducted to investigate the effects of the antimicrobial carbadox (CX) on bile acid metabolism in the young pig. The pigs were fed a fortified, 19.5% crude protein, corn-soybean meal diet without or with 55 ppm CX. In Exp. I pigs were fed the diets for 28 d, then the level of activity of hepatic cholesterol 7 alpha-hydroxylase (CH-7 alpha), the rate-limiting enzyme of bile acid metabolism, was measured. The CX-fed pigs gained faster (P less than .05) and more efficiently (P less than .05) and had lower (P less than .02) CH-7 alpha activity than the control pigs. In Exp. II, pigs ranging in weight from 12 to 15 kg were fitted with indwelling catheters in the hepatic portal (HP) and anterior vena cava (VC) veins. Radiolabeled chenodeoxycholic acid (CDC) was infused into the HP and blood samples from both veins were taken at meal time and hourly for 6 h following six meals over 3 d. Bile was collected 14 d after infusion. Concentrations of lithocholic acid (LC) in the bile and hyodeoxycholic acid (HDC) in the plasma were reduced by dietary CX. Dietary CX did not significantly affect metabolism of plasma CDC or hyocholic acid (HC) as measured by radioactivity. Meal time (0800 vs 1600) affected (P less than .05) plasma CDC radioactivity at all times and the level of HDC radioactivity 2 h post-prandial. There was a meal time X dietary treatment interaction (P less than .02) on plasma HC radioactivity 2 h post-prandial. These data suggest that dietary CX inhibited intestinal microbial degradation of CDC and HC.
进行了两项试验以研究抗菌药卡巴氧（CX）对幼猪胆汁酸代谢的影响。给猪饲喂一种强化的、粗蛋白含量为19.5%的玉米-豆粕型日粮，日粮中添加或不添加55 ppm的CX。在试验I中，猪饲喂这些日粮28天，然后测定胆汁酸代谢的限速酶——肝脏胆固醇7α-羟化酶（CH-7α）的活性水平。与对照猪相比，饲喂CX的猪增重更快（P<0.05）且效率更高（P<0.05），CH-7α活性更低（P<0.02）。在试验II中，体重12至15 kg的猪在肝门静脉（HP）和前腔静脉（VC）中植入留置导管。将放射性标记的鹅去氧胆酸（CDC）注入HP，并在3天内的6餐进食时及餐后每小时采集来自两条静脉的血样，共采集6小时。在注入后14天收集胆汁。日粮中的CX降低了胆汁中石胆酸（LC）的浓度和血浆中猪去氧胆酸（HDC）的浓度。通过放射性测定，日粮中的CX对血浆CDC或猪胆酸（HC）的代谢没有显著影响。进食时间（08:00对16:00）在所有时间均影响（P<0.05）血浆CDC放射性以及餐后2小时的HDC放射性水平。餐后2小时，血浆HC放射性存在进食时间×日粮处理的交互作用（P<0.02）。这些数据表明，日粮中的CX抑制了肠道微生物对CDC和HC的降解。
