14 Evaluation of the absorption of various nutraceuticals in horses at different fed rates

Abstract

Nutraceuticals are non-nutritive additives aimed at providing health benefits to the horse. Determining the efficacy of these nutraceuticals should start with an understanding of their absorption when administered through feeding. To determine the in vivo absorption of a variety of nutraceutical compounds, a trial was conducted in which various products were fed at increasing concentrations and blood samples evaluated for biomarkers. Two groups of mature Quarter Horses (n = 5 per group) were utilized in feeding trials in which compounds were fed at increasing levels over a 3 wk period. Horses were offered each amount for a period of 7 d. Horses in group 1 consumed turmeric at 3 levels (2 g/d, 20 g/d, 100 g/d), while horses in group 2 were offered hydrolyzed collagen (40 g/d, 80 g/d, 120 g/d). Following a 1 wk washout, horses in group 1 were offered green tea encapsulated in a phytosome (1 g/d, 10 g/d, 100 g/d), while horses in group 2 were offered pure green tea (0.3 g/d, 2.6 g/d, 25 g/d). Both groups received identical amounts of green tea as the phytosome form was approximately 20% green tea. Following a 1 wk washout, horses in group 1 were offered cranberry powder (10 g/d, 20 g/d, 80 g/d). All nutraceuticals were top dressed on 1.81 kg of Purina Ⓡ Omolene 200 Ⓡ twice daily at 0700 and 1500 in individual stalls. Horses were offered 1.5% BW as Timothy hay and had free-choice access to salt and water with daily turnout to drylots by group. Blood was obtained before the start of the trial and on d 1, 3, and 7 of supplementation for each compound. Serum samples were analyzed for metabolites for each compound via liquid-chromatography mass-spectrometry according to the table below. Data were analyzed using the MIXED procedure in SAS 9.4 (Cary, NC). For all dosages, turmeric biomarkers were difficult to identify in samples indicating negligible absorption. Samples from green-tea fed horses indicated that there was no difference in the phytosome vs. non-phytosome versions ( P > 0.05 ) with linear increases in serum EGCG corresponding with dosage ( P < 0.05 ). Glycine was the most consistent marker of hydrolyzed collagen absorption with a linear increase corresponding to dosage ( P < 0.05 ). Benzoic acid was only identified in samples at the 80 g/d dosage. These data are useful in developing future studies aimed at identifying the efficacy of these compounds. Utilizing these data can guide feeding amounts for further investigation.