Säkkinen H, Stien A, Holand O, Hove K, Eloranta E, Saarela S, Ropstad E
Department of Biology, University of Oulu, Oulu, Finland.
Physiol Biochem Zool. 2001 Nov-Dec;74(6):907-16. doi: 10.1086/324567.
Variation in plasma urea and creatinine concentration and plasma urea:creatinine ratio (U:C) were studied in semidomestic free-ranging reindeer (Rangifer tarandus tarandus) on the Norwegian mainland, in wild Svalbard reindeer (Rangifer tarandus platyrhynchus), and in captive reindeer maintained either on a lichen-based diet or a protein-rich concentrate to investigate whether these parameters could be used as indicators of the nutritional status of reindeer. In the mainland animals, plasma creatinine concentration was high in winter and early spring and decreased by two-thirds toward the summer. The overall range in mean plasma creatinine concentration (+/-SE) was from 90+/-1.26 to 280+/-2.88 micromol/L. Mean plasma urea concentration (+/-SE) varied from 2.46+/-0.10 in winter up to 17.44+/-0.29 mmol/L in summer and autumn. Month of sampling explained 65% and 90% of the variation in plasma urea and creatinine concentrations, respectively, indicating that seasonality in the diet had the greatest influence on these parameters. Reindeer given lichens as the only feed showed an increase in plasma creatinine and a decrease in plasma urea concentration. Food restriction caused a temporary elevation in urea level but had no significant effect on plasma creatinine concentration. The slight effect of energy intake on urea and creatinine levels was supported by the fact that severe undernutrition in the Svalbard reindeer population had only a small effect on plasma urea and creatinine levels. Protein-rich pellet feed increased plasma urea from around 3 mmol/L to above 10 mmol/L and reduced creatinine concentrations to less than 100 micromol/L, suggesting that the protein content of forage is an important determinant of these blood parameters. Mean U:C ratio (+/-SE) in plasma varied from 8.9+/-0.28 to 120.8+/-1.88. Ratios above 20 appeared when protein intake was low and energy intake was restricted or when protein intake was high. Low ratios occurred when protein intake was low but energy intake adequate. Plasma urea and creatinine concentrations and the U:C ratio showed complex dynamics that were affected by both season and the protein and feed intake. We conclude that they appear to be difficult to interpret as single measures of nutritional status of reindeer.
对挪威大陆半家养散养驯鹿（Rangifer tarandus tarandus）、野生斯瓦尔巴德驯鹿（Rangifer tarandus platyrhynchus）以及以地衣为食或富含蛋白质的浓缩饲料饲养的圈养驯鹿的血浆尿素和肌酐浓度以及血浆尿素：肌酐比值（U:C）的变化进行了研究，以调查这些参数是否可作为驯鹿营养状况的指标。在大陆的驯鹿中，冬季和早春血浆肌酐浓度较高，到夏季时下降了三分之二。平均血浆肌酐浓度（±SE）的总体范围为90±1.26至280±2.88微摩尔/升。平均血浆尿素浓度（±SE）从冬季的2.46±0.10变化到夏季和秋季的17.44±0.29毫摩尔/升。采样月份分别解释了血浆尿素和肌酐浓度变化的65%和90%，表明饮食的季节性对这些参数影响最大。仅以地衣为唯一饲料的驯鹿血浆肌酐升高，血浆尿素浓度降低。食物限制导致尿素水平暂时升高，但对血浆肌酐浓度无显著影响。能量摄入对尿素和肌酐水平的轻微影响得到了以下事实的支持：斯瓦尔巴德驯鹿种群的严重营养不良对血浆尿素和肌酐水平的影响很小。富含蛋白质的颗粒饲料使血浆尿素从约3毫摩尔/升增加到10毫摩尔/升以上，并使肌酐浓度降低到100微摩尔/升以下，这表明饲料中的蛋白质含量是这些血液参数的重要决定因素。血浆中平均U:C比值（±SE）从8.9±0.28变化到120.8±1.88。当蛋白质摄入量低且能量摄入受限或蛋白质摄入量高时，比值会高于20。当蛋白质摄入量低但能量摄入充足时，比值会较低。血浆尿素和肌酐浓度以及U:C比值呈现出受季节以及蛋白质和饲料摄入量影响的复杂动态变化。我们得出结论，它们似乎难以作为驯鹿营养状况的单一衡量指标来解读。
