Serum amino acid profiles in clinically normal Noma horses

Abstract

Plasma or serum amino acids are used to evaluate nutritional status and metabolic disorders. In this study, we aimed to set reference values of serum amino acid concentrations in the Noma horse, a Japanese native horse. Thirty-one horses were classified into six age groups: neonatal foal (0-4 days), foal (0.5-1 years), youth (5 years), middle age (10 years), old (15 years), and extra-old (>20 years). Horses >5 years of age were analyzed together as the adult group. In the adult horses, there were no significant differences among the serum amino acid concentrations of each age group. The foal group had higher concentrations of alanine, aspartic acid, glutamic acid, α-aminoadipic acid, and 3-methyl-histidine than the adult group. The neonatal foal group had higher serum concentrations of phenylalanine, lysine, alanine, proline, aspartic acid, glutamic acid, β-alanine, and β-amino-iso-butyric acid and lower tryptophan concentrations and Fischer's ratios than the adult group. The neonatal foal group had higher β-amino-iso-butyric acid concentrations and lower tryptophan and 3-methyl-histidine concentrations than the foal group. Therefore, reference values might be set separately in neonatal foals, foals, and adult horses. The data for the serum amino acid concentrations can be used for health care through physiological and pathological evaluations in Noma horses.

Keywords: Noma horse; reference value; serum amino acid.

Fig. 1.

A typical section of the breeding facility for Noma horses. (a) The stables where five Noma horses were kept had a roof, concrete floor, and open upper area on the feed trough side. All horses had free access to water and feed from troughs. The areas of the stables ranged from 43 to 92 m². (b) Paddocks were sandy areas surrounded by fences adjacent to the stables. All horses were free to move between stables and paddocks. The areas of the paddocks ranged from 35.5 to 105 m². (c) All horses had free access to feed in a feed trough (320 cm long, 72 cm wide, and 20 cm deep) at the front of the stables.