Immunological response to long-term transport stress in mature horses and effects of adaptogenic dietary supplementation as an immunomodulator.
BACKGROUND
Little information exists on the immunological effects of transport or the use of supplements to minimise transport stress.


OBJECTIVE
To establish baseline ranges and evaluate immunophenotypic and functional changes associated with transport and a nutritional 'adaptogen' supplement.


METHODS
Horses received either supplement (n = 10) or placebos (n = 9) during the 30 day study. After 28 days in stalls, 12 horses (6 supplement; 6 placebo) were transported for 24 h, then unloaded and recovered. Venous blood samples were collected on Days 1, 14 and 28 to establish baselines, and on Days 28, 29 and 30 to examine changes during transport and recovery.


RESULTS
Transport prompted elevations (P<0.05) in cortisol concentration, neutrophil count and white blood cell counts, while lymphocyte subpopulation counts (CD3+, CD4+, CD8+, CD21+) decreased (P<0.05). Normal phenotypic lymphocyte profiles returned within 24 h of recovery. Supplement effects on immunophenotype (CD21+ and CD8+) were observed in stabled horses (P<0.05), but not in transported horses.


CONCLUSIONS
These results provide insights into the immunological mechanisms associated with long-term transport.


CONCLUSIONS
The existence of a small window of immunological uncertainty follows long-term transportation, enhancing the potential risk of infectious disease in susceptible individuals.
Stull
C L
CL
Department of Veterinary Medicine Extension, University of California, Davis, California 95616, USA.
Spier
S J
SJ
Aldridge
B M
BM
Blanchard
M
M
Stott
J L
JL
D000818:Animals; D019587:Dietary Supplements; D005260:Female; D006736:Horses / Q000097:blood / Q000276:immunology*; D006854:Hydrocortisone / Q000097:blood; D007155:Immunologic Factors / Q000097:blood / Q000276:immunology; D007958:Leukocyte Count / Q000662:veterinary; D008213:Lymphocyte Activation; D008297:Male; D009504:Neutrophils / Q000276:immunology; D010936:Plant Extracts / Q000008:administration & dosage*; D011897:Random Allocation; D013312:Stress, Physiological / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D013601:T-Lymphocytes / Q000276:immunology*; D014186:Transportation
D007155:Immunologic Factors; D010936:Plant Extracts; D006854:Hydrocortisone