Lippia citriodora extract supplementation (provided at 1 mg/kg or 0.5 mg/kg metabolic body weight per day) didn’t affect the yearlings’ growth or weight gain, but it did have a positive effect on blood parameters, said Francesco Vizzarri, PhD, of the University of Bari Department of Agricultural and Environmental Science. He worked in collaboration with researchers from the University of Molise Department of Agricultural, Environmental, and Food Sciences, also in Italy.
That improved blood profile would suggest better welfare, he said. Specifically, the supplement improved the yearlings’ blood lipids and oxidative plasma profiles while causing a decrease in transaminases and total bilirubin, said Vizzarri. This implies the horses experienced enhanced liver function, likely because the polyphenols in the extract helped limit cellular damage in the liver by reducing the number of damage-causing free radicals.
The researchers’ plasma analyses revealed a marked increase in vitamins E and A circulating in the blood. These vitamins can also help control free radicals.
Vizzarri noted that, in this study, the team did not explore stress-related behaviors.
“The oxidative stress we investigated is related to the management of farming animals, to environmental conditions on the farm, and to other stress-related factors,” he said.
The team concluded that, “based on obtained results … dietary supplementation with L. citriodora extract might find a useful application in horse feeding, with positive impact observed in blood parameters and plasma oxidative markers, with beneficial effects on the physiological welfare of livestock animals,” they said.
The study, “Dietary effect of lemon verbena extract on selected blood parameters and on plasma oxidative profile in Avelignese horses,” was published in the Animal Science Journal.