Vitamin E is the major contributor to the antioxidant capacity in lambs fed whole dried citrus pulp

The aim of this study was to investigate the effect of dietary whole dried citrus pulp (DCP) on the antioxidant status of lamb tissues.In total, 17 lambs were divided into two groups and fed for 56 days: a barley-based concentrate diet (CON – eight animals), or aconcentrate-based diet including 35% DCP to partially replace barley (CIT – nine animals). The CIT diet contained a doubleconcentration of phenolic compounds than the CON diet (7.9 v. 4.0 g/kg dry matter (DM), respectively), but had no effect ( P>0.05) onthe overall antioxidant capacity of the hydrophilic fraction of blood plasma, liver and muscle. The CIT diet contained clearly moreα-tocopherol than the CON diet (45.7 v. 10.3 mg/kg DM), which could explain the higher concentration of α-tocopherol in liver, plasmaand muscle ( P<0.05). The dietary treatment had no effect on the extent of lipid peroxidation, measured as thiobarbituric acid andreactive substances assay (TBARS values) in the faeces, small intestine, liver, plasma and muscle. Nevertheless, when musclehomogenates were incubated in the presence of Fe3+/ascorbate to induce lipid peroxidation, the muscle from lambs fed DCP displayedlower TBARS values ( P<0.01), which negatively correlated with the concentration of α-tocopherol in muscle. These results showedthat feeding whole DCP to ruminants increases the antioxidant status of muscle through an increase in the deposition of α-tocopherol.