Responses of Plasma Acetate Metabolism to Hop (Humulus lupulus L.) in Sheep

An isotope dilution method using [1-(13)C]sodium (Na) acetate was conducted to determine the effect of feeding hop (Humulus lupulus L.) residues on plasma acetate metabolism in six adult crossbred sheep. The sheep were fed 63 g/kg BW(0.75)/d of either mixed hay (MH-diet) of orchardgrass (Dactylis glomerata L.) and reed canarygrass (Phalaris arundinacea L.) at a 60:40 ratio or MH-diet and hop-residues (Hop-diet) at 85:15 ratio with a crossover design for each of 3 week period. The isotope dilution method using single injection of [1-(13)C]Na acetate was performed thrice; before feeding (BF), 2 h after feeding (2F) and 4 h after feeding (4F), on the 21(st) day of each dietary treatment. Plasma acetate concentration tended to increase (P= 0.06) and turnover rate was numerically higher (P= 0.16) for MH-diet than Hop-diet. Plasma glucose, NEFA, VFA and lactic acid concentrations were similar between dietary treatments. In both the diets, although plasma concentration of acetate did not change, turnover rate increased significantly (P= 0.02) 2F than BF. Hop-residues did not show any negative impacts on acetate metabolism as well as physiology of animals in the present experimental conditions, hence thereby it could be used as an alternative to MH-diet for rearing sheep.