Effects of Different Oral Doses of Sodium Chloride on the Basal Acid-Base and Mineral Status of Exercising Horses Fed Low Amounts of Hay

Abstract

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.

Changes in haematological and biochemical parameters in blood serum of horses during exposition to workload stress

“…Another study focused on effects of dosages of NaCl on mineral status of exercising horses observed serum concentrations of chlorides in horses subjected to similar load as in our experiment [ 15 ]. Their findings shown concentrations ranged from 101 to 105 mmol/l which is in agreement with our results that ranged between 101.7 to 102.9 mmol/l over the course of the experiment and the values were within reference range.…”

Insights into the Physiological and Biochemical Impacts of Salt Stress on Plant Growth and Development

“…Proline used at higher concentrations may prove to be lethal for the plant, causing ultra-structural damages leading to ROS generation [178]. The effective dose of proline varies with genotype and plant developmental stage [179][180][181][182]. Proline accumulation has been reported for drought sensitive and tolerant barley genotypes grown under saline conditions.…”

Sensitivity of ponies to sodium in the drinking water

“…This is in agreement with the study of Schryver et al (1987), where a diet containing 5% NaCl exerted no adverse effect on mature gelding ponies. Similarly, warmblood horses in moderate work receiving up to 100‐g NaCl/day together with the concentrates remained healthy (Zeyner et al, 2017).…”