GA 2017

Phytogenic feed additives containing bioactive plant compounds have a beneficial impact on animal health and production. Plant compounds undergo a biotransformation in the animal organism and the resulting conjugates may bear different biological activities than the parental compounds. The study of intestinal absorption (IA) of individual compounds, their distribution within the body and biotransformation is fundamental for understanding their mode of action and the prediction of the optimal dosage. The goal of the current experiment was a quantification of thymol (the main compound of thyme oil) and thymol sulfate (product of thymol biotransformation) in duodenal wall, liver and blood plasma of broiler chickens fed a diet containing Thymus vulgaris L. essential oil (TEO) in different concentrations. Thirty-two 1-day old Ross-308 hybrid broiler chickens were divided into dietary treatments with TEO addition: 0%; 0.01%; 0.05%; 0.1% (w/w). Samples of tissues and blood plasma (BP) were collected after 4 weeks of supplementation. Concentrations of thymol were analysed after the enzymatic cleavage of thymol metabolites by the method SPME-GC-MS. Thymol sulfate was quantified without enzymatic hydrolysis using UHPLC-ESI-QTOF-MS. Concentrations of thymol and thymol sulfate in duodenal wall, liver and BP significantly increased with the highest TEO supplementation. A significant correlation was observed between the thymol and thymol sulfate concentrations in duodenal wall. Results probably outline the relation between thymol IA and the subsequent biotransformation. The proportion of thymol and thymol sulfate in liver in comparison to the duodenal wall decreased with the increasing TEO supplementation. Observations could support the assumption that the liver could adapt to a higher thymol supplementation with an intensive rate of the biotransformation and the subsequent excretion. Our results confirmed the thymol IA and the presence of its metabolite in BP and tissues on all dietary levels. The research was supported by the Slovak Scientific Agency VEGA, project 2/0078/16.