Effect of oregano oil on growth performance, rumen fermentation parameters and blood metabolites of growing lambs

Abstract

Increasing dietary concentrations of oregano oil (from zero to 1200 mg/kg diet DM) in a low-fibre fattening diet fed to growing lambs (n = 40; initial weight 22.2 ± 0.05 kg) did not affect feed intake but had negative effects on live weight gain and feed conversion. The depressed growth performance appeared to be due to the direct effect of the oil depressing the rumen fermentation and the consequent supply of essential nutrients - glucose and amino acids - needed for efficient growth and feed conversion.