Total (free and ester forms)l-carnitine concentrations in fresh 0-d yolks, 18-d yolk sacs, and 18-d embryo livers in eggs from broiler breeder hens that received no supplemental l-carnitine were determined to be 1.85, 4.15, and 28.9 mg/kg of tissue,respectively (Peebles et al., 2007).