Work undertaken at the Equine Research Centre at the University of Guelph in Canada has shown that low doses of ginseng in the lead-up to an inoculation improves a horse's antibody response when they receive a vaccination for equine herpesvirus 1 (EHV-1).
The American ginseng (Panax quinquefolium) made the vaccination more effective.
Researchers Wendy Pearson (Geulph), Semir Omar (University of Ottawa), and Andrew Clarke (University of Melbourne) undertook the research to determine if ginseng fed at low levels enhanced a horse's antibody response to the vaccine.
For 28 days, five horses received ground, powdered ginseng (35 milligrams per kilogram of body weight, delivering 1.7 milligrams per kilogram of the active ingredient in ginseng - ginsenosides). It was mixed in with molasses.
Five other horses received molasses only.
After 14 days, all horse in the study were vaccinated against EHV-1, and their immune responses monitored.
The antibody response to the vaccination was significantly quicker in the horses supplemented with ginseng, with a "clinically relevant" increase in antibodies to the virus being observed after two days, as opposed to six for the control group.
The horses receiving ginseng also had a significant decrease in serum levels of sodium and a significant increase in serum levels of potassium, the researchers wrote.
"No adverse effects of ginseng treatment were identified by hematologic and blood biochemistry profiles. Thus, low-dose dietary supplementation with ginseng in healthy horses may be a useful adjunct to vaccination."
The researchers chose the vaccine against EHV-1 as it typically produces a poor antibody response and provides incomplete protection against infection. The authors noted that research had previously shown that ginsenosides have been associated with increased antibody responses to vaccination in guinea pigs, pigs, mice, and dairy cattle.
However, those studies used injections of ginseng or ginseng extract, or both.
"Although the practice shows considerable promise, this method of administration is impractical for people working with horses in the field.
"Our study has demonstrated that dietary ginseng, at a daily dose of 35 mg/kg body weight for two weeks before and two weeks after parenteral EHV-1 vaccination, significantly improves the early time course and magnitude of the antibody response in horses, in addition to influencing the serum electrolyte balance."