Low dose exogenous erythropoietin elicits an ergogenic effect in standardbred horses.
BACKGROUND
Recombinant human erythropoietin (rhuEPO) causes an increase in red blood cell production and aerobic capacity in other species; however, data are lacking on effects in the horse.


OBJECTIVE
This study tested the hypothesis that rhuEPO administration would alter red cell volume (RCV), aerobic capacity (VO2max) and indices of anaerobic power.


METHODS
Eight healthy, unfit mares accustomed to the laboratory and experimental protocols were randomly assigned to either a control (CON, n = 4; 3 ml saline 3 times/week for 3 weeks) or EPO group (EPO, n = 4, 50 iu/kg bwt rhuEPO/3 ml saline 3 times/week for 3 weeks). Exercise tests (GXT) were performed on a treadmill (6% incline), 1 week before and 1 week after treatment. The GXT started at 4 m/sec, with a 1 m/sec increase every 60 sec until the horse reached fatigue. Oxygen uptake was measured via an open flow indirect calorimeter. Blood samples were collected before, during (each step) and 2 and 15 min post GXT to measure packed cell volume (PCV), haemoglobin concentration (Hb), blood lactate concentration (LA) and plasma protein concentration (TP). Plasma volume (PV) was measured using Evans Blue dye. Blood volume (BV) and RCV were calculated using PCV from the 8 m/sec step of the GXT.


RESULTS
There were no alterations (P>0.05) in any parameters in CON horses. By week 3, EPO produced increases (P<0.05) in resting PCV (37 +/- 2 vs. 51 +/- 2) and Hb (37%). RCV (26%) and VO2max (19%) increased, but BV did not change (P>0.05) due to decreased PV (-11%, P<0.05). There was a significant increase in velocity at VO2max and LApeak for horses treated with rhuEPO and substantial decrease (P<0.05) in VO2 recovery time when the pretreatment GXT was compared to the post treatment GXT. No differences (P<0.05) were detected for TP, VLA4, run time or Vmax.


CONCLUSIONS
Low dose rhuEPO administration increases RCV and aerobic capacity without altering anaerobic power.


CONCLUSIONS
This study demonstrates that rhuEPO enhances aerobic capacity and exercise performance, a question relevant to racing authorities.
McKeever
K H
KH
Equine Science Center, Department of Animal Sciences, Rutgers the State University of New Jersey, 84 Lipman Drive, New Brunswick, New Jersey, 08901-8525, USA.
Agans
J M
JM
Geiser
S
S
Lorimer
P J
PJ
Maylin
G A
GA
D000818:Animals; D002153:Calorimetry, Indirect / Q000662:veterinary; D004300:Doping in Sports; D004911:Erythrocyte Volume / Q000187:drug effects / Q000502:physiology / Q000662:veterinary*; D004921:Erythropoietin / Q000494:pharmacology*; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006736:Horses / Q000097:blood* / Q000502:physiology; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011994:Recombinant Proteins
D006454:Hemoglobins; D011994:Recombinant Proteins; D004921:Erythropoietin