Blood thiamine (vitamin B1 ), ascorbic acid (vitamin C), and cortisol concentrations in healthy and ill neonatal foals

Pharmacologic Interventions to Immunologic and Immune-Mediated Conditions in Horses

Immunomodulators can stimulate, suppress, or regulate one or many aspects of the immune response. Use of a variety of immunostimulants, immunosuppressors, and anti-inflammatory drugs are described in horses, but the evidence supporting their efficacy is variable. Corticosteroids and nonsteroidal anti-inflammatory drugs are the best characterized immunomodulators in horses, but further study is needed to fully define their ideal dosing protocols and indications and to characterize the efficacy of other immunomodulators in equine medicine.

Blood thiamine (vitamin B1 ), ascorbic acid (vitamin C), and cortisol concentrations in healthy and ill neonatal foals

Background

Sepsis is common in foals and several treatments are used to facilitate recovery. Evidence in people suggests an association between low blood concentrations of thiamine, ascorbic acid, and cortisol and sepsis, with further evidence suggesting that administration of hydrocortisone, thiamine, and ascorbic acid may improve outcome. No information is available with regard to these treatments in foals.

Hypothesis/Objectives

To compare blood concentrations of thiamine, ascorbic acid, and cortisol in healthy and ill foals.

Animals

Fifteen healthy and 27 ill (septic and sick‐nonseptic [SNS]) foals were evaluated at admission. Fewer healthy and ill foals were available for sampling at 72 and 120 hours.

Methods

Prospective study. Blood was collected from healthy foals at 12 (n = 15), 72 (n = 11), and 120 (n = 9) hours of age and from ill foals <48 hours old at admission (n = 27), 72 (n = 8), and 120 (n = 8) hours after presentation. Thiamine, ascorbic acid, and cortisol concentrations were measured in blood samples and compared between groups of foals.

Results

Blood concentrations of thiamine were significantly lower in septic compared to healthy foals at 72 (median, 1.72 ng/mL; P = .02) and 120 (median, 2.0 ng/mL; P = .04) hours after admission; blood concentrations of ascorbic acid also were significantly lower in septic compared to healthy foals at 72 (median, 4.4 μg/mL; P = .02) and 120 hours (median, 4.8 μg/mL; P = .03). Blood concentrations of ascorbic acid were lower in SNS compared to healthy foals at 72 (median, 6.9 μg/mL; P = .03) and 120 (median, 6.4 μg/mL; P = .04) hours after admission. Serum cortisol concentrations were significantly higher at admission in septic (median, 4.23 μg/dL) compared to SNS (median, 1.8 μg/dL; P = .01) and healthy (median, 2.2 μg/dL; P = .002) foals.

Conclusions and Clinical Importance

A potential association exists between illness in foals and lower blood concentrations of thiamine and ascorbic acid during hospitalization. Additional studies are needed to examine a larger population of foals and determine the clinical impact of low vitamin concentrations, if any, on morbidity and mortality.