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.
Publication Date: 2017-01-03 PubMed ID: 28045916PubMed Central: PMC5207637DOI: 10.1371/journal.pone.0168325Google Scholar: Lookup
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Summary
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This research investigates the effect of different doses of sodium chloride (NaCl) intake on the balance of acid and base (acid-base status) and mineral content in horses. The study finds that high levels of NaCl supplementation can lead to mild acidosis in moderately exercising horses, while moderate NaCl intake can result in compensated acidosis.
Study Design and Procedure
- The study was conducted on six adult warmblood mares in moderate work. The horses received diets of fodder (hay) and unprocessed cereal grains.
- Three different levels of NaCl were fed to the horses alongside their regular meals. These were 0g (NaCl-0), 50g (NaCl-50) and 100g (NaCl-100). This feeding process was carried out over 2 equal doses for a period of 3 weeks.
- Factional electrolyte clearances (FC) were determined, and a mineral digestibility trial was carried out during the final week.
- To trace the changes, blood and urine samples were collected at several points throughout the study – on days 0, 1-4, 8, and 15. These samples were tested for pH levels, acid-base status and electrolyte concentrations.
Key Findings
- The average apparent sodium digestibility was between 60-62%. Chloride digestibility was consistently above 94%.
- The horses that were given the higher dose (100g) of NaCl had significant reduction in blood pH and base excess as well as urinary pH and urine acid excretion. This means that their blood and urine became more acidic.
- Both 50g and 100g of NaCl supplementation led to a significant reduction in base and net acid-base excretion, urine density and potassium concentration. However, it increased the urine sodium concentration and the fractional clearance (FC) of sodium and chloride. This indicates that a large portion of the salt was excreted through the kidneys.
- The alterations in acid-base balance and mineral content due to the NaCl supplementation persisted for the entire 2 week measurement period.
Conclusions
- The study found that feeding 100g of NaCl to moderately exercising horses leads to mild acidosis, a condition where body fluids have too much acid.
- By contrast, a 50g supplementation of NaCl, which is the typical amount recommended for horses in moderate work, resulted in compensated acidosis – a maintained pH level despite changes in acid concentration.
Cite This Article
APA
Zeyner A, Romanowski K, Vernunft A, Harris P, Müller AM, Wolf C, Kienzle E.
(2017).
Effects of Different Oral Doses of Sodium Chloride on the Basal Acid-Base and Mineral Status of Exercising Horses Fed Low Amounts of Hay.
PLoS One, 12(1), e0168325.
https://doi.org/10.1371/journal.pone.0168325 Publication
Researcher Affiliations
- 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.
- Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany.
- Equine Studies Group, Waltham Centre for Pet Nutrition, Waltham-on-the-Worlds, United Kingdom.
- Chair for Nutritional Physiology and Animal Nutrition, University of Rostock, Rostock, Germany.
- State Office for Agriculture, Food Safety and Fishery Mecklenburg-Western Pomerania, Rostock, Germany.
- Institute of Physiology and Animal Nutrition, Ludwig-Maximilian University Munich, Munich, Germany.
MeSH Terms
- Acid-Base Equilibrium
- Acidosis
- Animal Feed / analysis
- Animals
- Body Weight
- Dietary Supplements
- Electrolytes / blood
- Feces
- Female
- Horses / physiology
- Hydrogen-Ion Concentration
- Physical Conditioning, Animal
- Poaceae
- Potassium / blood
- Sodium Chloride, Dietary / administration & dosage
- Sodium, Dietary / blood
- Temperature
Conflict of Interest Statement
“Consumables from the research were funded by WALTHAM Centre for Pet Nutrition. This does not alter our adherence to PLOS ONE policies on sharing data and materials.”
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