Zeyner Annette, Romanowski Kristin, Vernunft Andreas, Harris Patricia, Müller Ann-Marie, Wolf Carola, Kienzle Ellen
Institute of Agricultural and Nutritional Sciences, Group Animal Nutrition, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
Chair for Nutritional Physiology and Animal Nutrition, University of Rostock, Rostock, Germany.
PLoS One. 2017 Jan 3;12(1):e0168325. doi: 10.1371/journal.pone.0168325. eCollection 2017.
The provision of NaCl, according to current recommendations, to horses in moderate work has been shown to induce immediate postprandial acidosis. The present study aimed to clarify whether this NaCl induced acidosis i) persists beyond the immediate postprandial period, and ii) is still present after a 2 week adaptation period. Six adult warmblood mares in moderate work received daily 1.00 kg hay per 100 kg body weight (bwt) only together with 0.64 kg unprocessed cereal grains/100 kg bwt.d as fed basis. Using a 3x3 Latin Square, either 0 (NaCl-0), 50 (NaCl-50) or 100 (NaCl-100) g NaCl/d were fed together with the concentrates in two equal doses for 3 weeks. During the final week, a mineral digestibility trial was undertaken. The middle sodium and chloride intake (NaCl-50) at least met the most common recommendations for moderate work. Morning (7:00 AM) urine and venous blood samples were collected on days 0, 1-4, 8, and 15, and analysed for pH, acid-base status, creatinine and electrolyte concentrations. Fractional electrolyte clearances (FC) were determined. Mean apparent sodium digestibility ranged between 60-62% whereas chloride digestibility was consistently above 94%. Supplementing 100 g but not 50 g of NaCl resulted in significant reduction of blood pH and base excess as well as urinary pH and urine acid excretion. Both 50 g and 100 g NaCl supplementation caused a significant reduction in base and net acid-base excretion, urine density and potassium concentration, but increased urine sodium concentration and the FC of sodium and chloride (P < 0.05). This suggests that a high proportion of the recommended salt doses is excreted renally. The above effects of NaCl supplementation persisted over the 2 week measurement period. Results suggest that feeding 100 g NaCl to moderately exercising horses results in mild metabolic acidosis, whereas feeding 50 g according to current recommendations resulted in compensated acidosis.
根据目前的建议，给中等运动量的马匹提供氯化钠已被证明会导致餐后立即酸中毒。本研究旨在阐明这种由氯化钠引起的酸中毒：i）是否会在餐后立即阶段之后持续存在；ii）在2周的适应期后是否仍然存在。6匹中等运动量的成年温血母马，每天每100千克体重（bwt）仅给予1.00千克干草，以及0.64千克未加工谷物/100千克bwt.d（按喂食量计算）。采用3×3拉丁方设计，将0（NaCl-0）、50（NaCl-50）或100（NaCl-100）克氯化钠/天与浓缩饲料一起分两次等量投喂，持续3周。在最后一周，进行了矿物质消化率试验。中等钠和氯摄入量（NaCl-50）至少满足了中等运动量最常见的建议。在第0天、第1 - 4天、第8天和第15天的上午（上午7:00）采集尿液和静脉血样本，分析其pH值、酸碱状态、肌酐和电解质浓度。测定电解质清除率（FC）。平均表观钠消化率在60 - 62%之间，而氯消化率始终高于94%。补充100克而非50克氯化钠会导致血液pH值和碱剩余以及尿液pH值和尿酸排泄量显著降低。补充50克和100克氯化钠均导致碱和净酸碱排泄、尿密度和钾浓度显著降低，但尿钠浓度以及钠和氯的FC增加（P < 0.05）。这表明推荐盐剂量的很大一部分经肾脏排泄。补充氯化钠的上述影响在2周的测量期内持续存在。结果表明，给适度运动的马匹喂食100克氯化钠会导致轻度代谢性酸中毒，而按照目前的建议喂食50克会导致代偿性酸中毒。
