Wamberg S, Tauson A H, Elnif J
Department of Physiology, Odense University, Denmark.
Br J Nutr. 1996 Nov;76(5):711-25. doi: 10.1079/bjn19960078.
Daily (24 h) rates of water and electrolyte turnover were measured in a conventional balance study in ten adult female pastel mink (Mustela vison) given free access to a standard mink feed for a 1-week conditioning period, followed by a 4 d experimental period and a 2 d fasting period. Drinking water was available throughout. In addition, the completeness of urine collection and the fraction of urine collected with the faeces were determined using a new experimental technique based on 24 h recoveries of specific urinary markers such as tritiated p-aminohippuric acid ([3H]PAH) or 14C-labelled inulin ([14C]IN) continuously delivered by small Alzet osmotic pumps implanted intraperitoneally. During feeding the mean individual percentage recovery in urine of [3H]PAH released from the osmotic pumps ranged from 68 to 88% (median 78%). The mean percentage of urinary [3H]PAH recovered from faecal collections was 6% (range 3-12%). In response to fasting the mean individual percentage recovery of [3H]PAH in urine ranged from 62 to 78% (median 68%). For urinary [14C]IN the mean percentage recoveries in fed and fasted animals were 79 and 63% respectively. Furthermore, during fasting, withdrawal of the supplies of dietary water caused a slight but insignificant (P = 0.17) increase in the daily intake of drinking water and, hence, the animals maintained their normal water balance by a dramatic reduction in urine excretion (P < 0.001). At the same time urinary solute excretion declined significantly (P < 0.001), due in part to the cessation of dietary electrolyte intake and in part to reduced formation of urea, whereas urinary osmolality decreased only moderately. The mean 24 h balances of Na, K, Ca, Mg, Cl and P were close to zero and only minor differences between the feeding and fasting periods were observed. When corrected for the measured inaccuracies in urine collection the balance data obtained in the present study represent useful reference standards for normally fed and fasted non-growing mink and, to some extent, useful guidelines for future studies in experimental animals.
在一项常规平衡研究中，对10只成年雌性彩色水貂（鼬属）测定了水和电解质的每日（24小时）周转率。在为期1周的适应期内，让它们自由进食标准水貂饲料，随后是4天的实验期和2天的禁食期。整个过程中都提供饮用水。此外，使用一种新的实验技术来确定尿液收集的完整性以及随粪便收集的尿液比例，该技术基于通过植入腹腔的小型Alzet渗透泵持续输送的特定尿液标记物（如氚标记的对氨基马尿酸（[3H]PAH）或14C标记的菊粉（[14C]IN））的24小时回收率。在进食期间，从渗透泵释放的[3H]PAH在尿液中的平均个体回收率在68%至88%之间（中位数为78%）。从粪便收集物中回收的尿液[3H]PAH的平均百分比为6%（范围为3% - 12%）。禁食时，尿液中[3H]PAH的平均个体回收率在62%至78%之间（中位数为68%）。对于尿液[14C]IN，进食和禁食动物的平均回收率分别为79%和63%。此外，在禁食期间，停止供应膳食水导致饮用水的每日摄入量略有增加但不显著（P = 0.17），因此，动物通过显著减少尿液排泄（P < 0.001）来维持其正常的水平衡。同时，尿液溶质排泄显著下降（P < 0.001），部分原因是膳食电解质摄入的停止，部分原因是尿素形成的减少，而尿液渗透压仅适度降低。Na、K、Ca、Mg、Cl和P的平均24小时平衡接近零，并且在进食和禁食期之间仅观察到微小差异。当校正尿液收集测量中的不准确性时，本研究获得的平衡数据代表了正常进食和禁食的非生长水貂的有用参考标准，并且在一定程度上为未来实验动物研究提供了有用的指导方针。
