Free Plasma Amino Acid Concentrations in Horses Fed Different Dosing Regimens of Hydrolysed Collagen

Hydrolysed collagen is used as a supplement for horses with osteoarthritis, hoof horn growth problems, and gastric ulcers. To determine the oral availability of a specific hydrolysed collagen supplement and the appropriate dose, six Warmblood mares were fed two different concentrations of the supplement: 100 g HC (C_H), 50 g HC (C_L), and a control of 0 g HC (C_N) during one week in a randomised cross-over design. On day 7, 14 and 21, blood sampling for amino acid (AA) analysis was performed, just prior to feeding the supplement (t = 0) and every hour after feeding for 8 h (t = 1-8). Statistical analysis revealed differences in mean plasma AA concentrations between the CH and CN doses for alanine, arginine, glutamine, glycine, proline, serine and hydroxyproline. Similarly, statistical differences were observed between the CL and CN doses for arginine, glycine, proline and hydroxyproline. This study demonstrated the availability of amino acids from the supplemented hydrolysed collagen. Although clinical efficacy was not evaluated in this study, a dose of 100 g HC once daily resulted in higher plasma concentrations, which remained detectable for at least 24 h, suggesting greater clinical relevance.