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Plasma glutamine status in the equine at rest, during exercise and following viral challenge
Author(s) -
ROUTLEDGE NAOMI B. H.,
HARRIS R. C.,
HARRIS PAT A.,
NAYLOR J. R. J.,
ROBERTS C. A.
Publication year - 1999
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1999.tb05295.x
Subject(s) - horse , equine influenza , medicine , glutamine , endocrinology , zoology , chemistry , virus , biology , immunology , biochemistry , amino acid , paleontology
Summary The variation over 24 h of plasma glutamine concentration in nonexercising horses was studied in 3 Thoroughbreds (TB) fed at 1600 h and 0700 h. This indicated a small but regular change associated with feeding. Starting at a mean of 482 μmol/l at 1600 h the concentration increased to 522 μmol/l at 2000 h, falling to 476 μmol/l at 1600 h and increasing again to 525 μmol/l at 2000 h. ‘Normal’ values were established in 19 part‐bred TB horses, lacking clinical signs or remarkable pathology and in light training, by sampling weekly at 1000 h over a 10 week period. The mean concentration was 491 μmol/l. Values were normally distributed with 95% confidence range between horses of 469–512 μmol/l. The s.d. of values within‐horse was 28 μmol/l. The acute effect of exercise was investigated in 5 TB horses during i) an exercise simulating the road and tracks phase of a 3‐day‐event and ii) a sustained high‐intensity exercise test (115% V̇O 2max until the pace was no longer maintained). In both tests a transient increase was produced as a direct result of exercise, followed by a decline to a nadir at approximately 3 h post exercise. Pre‐exercise resting concentrations, following either test, were approaching pre‐values by 24 h recovery. The effect of viral challenge was studied in 6 TB horses exposed to an aerosol of equine influenza virus, subtype H3N8 (A/equine‐2 subtype) which caused mild clinical signs. A significant fall in the 1000 h plasma glutamine concentration from a mean of 463 to 342 μmol/l by the 6th day was seen in 5 horses. A more gradual decline was observed in the 6th horse. These findings indicate a similar response to viral challenge in the horse to that in man.