Penner Gregory B, Aschenbach Jörg R, Gäbel Gotthold, Rackwitz Reiko, Oba Masahito
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada.
J Nutr. 2009 Sep;139(9):1714-20. doi: 10.3945/jn.109.108506. Epub 2009 Jul 29.
Subacute ruminal acidosis (SARA) is a common digestive disorder occurring in ruminants, with considerable variation in the severity of SARA observed among animals fed the same diet. Our aim in this study was to determine whether differences in the capacity of the ruminal epithelium for the apical uptake of acetate and butyrate (determined in Ussing chambers after slaughter) explains differences observed for the severity of a preceding episode of SARA in vivo. Adult sheep with an indwelling small ruminant ruminal pH measurement system (SRS) were randomly assigned to either a SARA induction treatment (oral drench containing 5 g glucose/kg body weight; n = 17) or a sham treatment (SHAM; n = 7; 12 mL water/kg body weight). Sheep receiving the glucose drench were further classified as nonresponders (NR; n = 7) or responders (RES; n = 7) according to their ruminal pH profile for the 3 h following the oral drench. Mean ruminal pH for the 3 h following the drench differed among groups (P < 0.001), with it being highest for SHAM (6.67 +/- 0.08), intermediate for NR (5.97 +/- 0.05), and lowest for RES (5.57 +/- 0.08) sheep. The apical uptake of acetate and butyrate did not differ between SHAM and RES sheep. However, NR sheep had greater in vitro apical uptake of acetate and butyrate and a higher plasma beta-hydroxybutyrate concentration than RES sheep, suggesting greater absorptive capacity for NR. Differences between NR and RES were attributed to greater bicarbonate-independent, nitrate-sensitive uptake of acetate (P = 0.007), a tendency for greater bicarbonate-dependent uptake of acetate (P = 0.071), and greater bicarbonate-independent uptake of butyrate (P = 0.022). These data indicate that differences in the rates and pathways for the uptake of acetate and butyrate explain a large proportion of the individual variation observed for the severity of SARA.
亚急性瘤胃酸中毒（SARA）是反刍动物中常见的一种消化系统疾病，在采食相同日粮的动物中，SARA的严重程度存在相当大的差异。本研究的目的是确定瘤胃上皮对乙酸盐和丁酸盐顶端摄取能力的差异（屠宰后在尤斯灌流小室中测定）是否能解释之前体内SARA发作严重程度的差异。将植入小型反刍动物瘤胃pH测量系统（SRS）的成年绵羊随机分为SARA诱导处理组（口服含5 g葡萄糖/kg体重的灌服液；n = 17）或假处理组（SHAM；n = 7；12 mL水/kg体重）。根据灌服后3小时内的瘤胃pH曲线，接受葡萄糖灌服的绵羊进一步分为无反应者（NR；n = 7）或反应者（RES；n = 7）。灌服后3小时的平均瘤胃pH在各组间存在差异（P < 0.001），其中SHAM组最高（6.67 ± 0.08），NR组居中（5.97 ± 0.05），RES组最低（5.57 ± 0.08）。SHAM组和RES组绵羊对乙酸盐和丁酸盐的顶端摄取没有差异。然而，NR组绵羊在体外对乙酸盐和丁酸盐的顶端摄取量更高，血浆β-羟基丁酸盐浓度也高于RES组绵羊，这表明NR组的吸收能力更强。NR组和RES组之间的差异归因于乙酸盐的非碳酸氢盐依赖性、硝酸盐敏感性摄取增加（P = 0.007），乙酸盐的碳酸氢盐依赖性摄取有增加的趋势（P = 0.071），以及丁酸盐的非碳酸氢盐依赖性摄取增加（P = 0.022）。这些数据表明，乙酸盐和丁酸盐摄取速率和途径的差异解释了SARA严重程度个体差异的很大一部分。
