**5. Conclusions**

The results obtained in this study indicate that knotweed consumption helps (1) improve the immunity of horses by increasing their blood globulin levels, (2) stimulate lipid metabolism in cold-blooded horses and (3) lower cholesterol levels. These effects have been found in young and healthy horses and are expected to be more pronounced in older horses.

Because knotweed has the potential to stimulate the release of fat from hepatic cells and thus speed up liver regeneration processes, it could reduce the risk of adverse health consequences in horses with impaired lipid metabolism.

The sporting success of the horses involved in the experiments was monitored. Half of the foals from both the control and knotweed-fed groups have been in use in sports in the Czech Republic since 2018, i.e., 2 years after the second experiment. The knotweed-fed horses achieved slightly better results than control horses in jumping competitions.
