异生物素及其代谢物在反刍家畜体组织的分泌与排泄机理

Mechanisms of secretion and excretion of xenobiotics and their metabolits in ruminants

胆汁分泌和尿液排泄是异生物素如芳香族和脂环族化合物排出反刍动物有机体的主要途径。渗透过滤是胆汁分泌的主要机制,离子运输对共轭态异生物素的胆汁分泌具有重要作用,其影响因素主要为代谢物极性、分子量和结构。胆汁分泌促进了异生物素在动物体内持续地进行肠肝循环。肾脏中的分泌排泄过程在肾单位中进行。代谢物的尿液排泄包括3个基本过程:肾小球过滤、肾小管分泌和肾小管再吸收。家畜有机体排出异生物素的其他途径有唾液、乳汁、汗水和气体。家畜对某一特定饲料的采食量以及饲料本身的属性直接影响异生物素经尿液的排泄,以此建立合理的关系模型就可以根据尿液中的排泄量测定或预测家畜的采食量。

The main pathways by which body tissues eliminate xenobiotics, such as aromatic and alicylic compounds, are biliary secretion and renal excretion. Biliary secretion has an important role in the persistence of xenobiotics within animal tissues by enterohepatic circulation. The major mechanism of bile flow is osmotic filtration. For biliary secretion of conjugating xenobiotics, ionic transport is the main form which is influenced by metabolite polarity, compound molecular weight and structrure. The urine excretion process takes place in functional units of the kidney called nephrons and involves three primary processes: glomerular filtration, tubular secretion and tubular reabsorption. Other possible routes of xenobiotic elimination from the animal environment are saliva, milk, sweat and exhaled air. The attributes of feedstuff and the amount of a particular feed consumed by the animal, directly affect the urinary excretion of xenobiotics. If an inference model is set up accordingly, the feed intake of the animal can be measured or predicted.