Increased hepatic skatole exposure via rumen infusion increases skatole concentration in peripheral circulation and inter-muscular fat in sheep

摘要

Skatole meat taint is unique to pastoral systems where high forage digestibility results in tryptophan-derived skatole production at rates that exceed the clearance capacity of the liver. We hypothesise that under conditions of minimal endogenous skatole production (diet low in rumen degradable protein) a continuous rumen infusion of skatole will elevate hepatic exposure and modify tissue skatole metabolism. A 72 hour rumen infusion of skatole (140 mg/h; n = 6) dissolved in propane-1,2-diol (PD) or PD media alone (n = 6) was performed. Samples of rumen fluid and blood were collected at 0, 2, 4, 6, 8, 12, 16, 24, 48 and 72 hours for determination of skatole concentration. Infusion of skatole increased (P < 0.01) levels of skatole in rumen fluid (21 mu g/g), peripheral plasma (154 ng/ml) and inter-muscular fat (4240 ng/g). A two-compartment model was fitted to the rumen and plasma skatole concentration of treated sheep to estimate the rate of transfer from rumen to peripheral plasma (k = 0.23 ± 0.03/h) and the rate of elimination from peripheral circulation (k = 2.10 ± 0.56/h). A negative correlation (P < 0.05) between the rate of elimination and level of skatole deposition in inter-muscular fat was also found.