Huntington G B, Eisemann J H, Whitt J M
U. S. Department of Agriculture, Beltsville, MD 20705.
J Anim Sci. 1990 Jun;68(6):1666-73. doi: 10.2527/1990.6861666x.
We compared two techniques for measuring blood flow through portal-drained viscera (PDV) of beef steers and measured portions of cardiac output and total oxygen uptake attributable to PDV and hepatic tissues. Four steers (198 +/- 2 kg), equipped with chronic catheters in appropriate vessels, a transit-time ultrasound probe around the hepatic portal vein and a temporary cardiac output thermodilution catheter, were fed a 60:40 hay: concentrate diet. Treatments, designed to alter blood flow, were: 12 equal meals every 2 h (CNTL); CNTL plus 2 mg clenbuterol in one meal (CLEN); and a 65-h fast (FAST). Blood flow through PDV was measured by dilution of p-aminohippurate (PAH) and transit-time ultrasound. Hepatic blood flow was measured by PAH dilution and cardiac output was measured by thermodilution. Blood flow measured by transit-time ultrasound was consistently slower (45%, P less than .01) than blood flow measured by PAH dilution. Necropsy revealed anatomical constraints that precluded proper placement and function of the flow probes. Cardiac output (liters/h) was greater (P less than .05) for CLEN (3,082) than for CNTL (1,655) or FAST (1,047). Percentage of cardiac output flowing through PDV and hepatic tissues was less (P less than .05) for CLEN (23 and 24%) than for CNTL (31 and 38%) or FAST (32 and 38%). Whole body oxygen uptake (mmol/h) was greatest (P less than .05) for CLEN (4,220), intermediate for CNTL (2,999) and least for FAST (1,965). Percentage of oxygen uptake attributable to hepatic tissues was greater (P less than .05) for FAST (31%) than for CLEN (18%), with CNTL intermediate (24%). Percentage of oxygen uptake attributable to PDV (22%) was not affected (P greater than .05) by treatments.
我们比较了两种测量肉用公牛门静脉引流内脏（PDV）血流的技术，并测量了心输出量以及PDV和肝组织的总氧摄取量的相关部分。四头体重为198±2千克的公牛，在相应血管中植入慢性导管，在肝门静脉周围安装经时超声探头以及临时的心输出量热稀释导管，投喂60:40的干草：精料日粮。旨在改变血流的处理方式有：每2小时投喂12次等量日粮（对照组）；对照组加一餐中添加2毫克克伦特罗（克伦特罗组）；以及禁食65小时（禁食组）。通过对对氨基马尿酸（PAH）的稀释以及经时超声来测量PDV的血流。通过PAH稀释测量肝血流，通过热稀释测量心输出量。经时超声测量的血流始终比PAH稀释测量的血流慢（45%，P<0.01）。尸检发现解剖学上的限制因素，妨碍了血流探头的正确放置和功能。克伦特罗组的心输出量（升/小时）（3082）高于对照组（1655）或禁食组（1047）（P<0.05）。流经PDV和肝组织的心输出量百分比，克伦特罗组（23%和24%）低于对照组（31%和38%）或禁食组（32%和38%）（P<0.05）。全身氧摄取量（毫摩尔/小时），克伦特罗组（4220）最高（P<0.05），对照组（2999）居中，禁食组（1965）最低。禁食组（31%）归因于肝组织的氧摄取百分比高于克伦特罗组（18%）（P<0.05），对照组（24%）居中。处理方式对归因于PDV的氧摄取百分比（22%）没有影响（P>0.05）。
