No abstract

The effects of dietary fat supplementation on performance, fatty acid (FA) composition of tissues and antioxidant defence system of broilers were studied. Male broilers were placed in 20 floor pens (60 broilers per pen). The broilers were fed by diets with added different energy sources: lard (L); sunflower oil (SFO); soybean oil (SBO); and linseed oil (LSO). The treatments did not modify significantly growth performance and feed intake of the broilers. There was no effect of dietary FA pattern on reduced glutathione level and glutathione peroxidase activity of plasma, erythrocyte and liver samples. However, higher PUFA content of the diet resulted in a significant increase in malondialdehyde level of erythrocytes and liver. The broilers fed LSO diet more effectively maintained their antioxidant status with enhanced plasma radical scavenger capacity. FA composition in tissues reflected the FA pattern of the diets, although proportion of FAs with four or more double bonds was metabolic specific. LSO diet increased the level of C18:3, C20:5 and C22:6 in tissue lipids in relation to L, SFO and SBO diets. Significantly increased plasma radical scavenging capacity in concert with the enhanced C20:5 and C22:6 proportion in liver and muscle during LSO feeding indicate metabolic changes to counteract the oxidative injury. This may be related to the compounds produced after different biochemical pathways of n-6 and n-3 FAs.

Alcoholic dependence causes gradual exhaustion of the antioxidant capacity of erythrocytes, therefore this non-invasive measurement may be useful as a follow-up of the evolution of alcoholic liver disease. The results also suggest a gender susceptibility of alcohol toxicity.

Black radish (Raphanus sativus L. var. niger) root has been used in folk medicine since antiquity as a natural drug for the stimulation of bile function. According to in vitro studies the squeezed juice from black radish root exhibited significant antioxidant properties. In the present study, the beneficial effect of the black radish juice on some free radical reactions in rats fed with a diet rich in lipids (20% sunflower oil, 2% cholesterol, 0.5% cholic acid in normal chow) was examined. Thiobarbituric acid reactive substances and conjugated diene concentrations were significantly higher, while the antioxidant enzyme activities and the free radical scavenging capacity were lower in hyperlipidaemic rats compared with normal controls. Supplementation of the lipid-rich diet with black radish juice resulted in a significant improvement of the parameters mentioned above. Although the exact mechanism of the biologically active compounds in black radish on the lipid metabolism and lipid peroxidation is not clear yet, a beneficial effect of the drug was evident in alimentary hyperlipidaemia.

The hepatoprotective property of silymarin is well known. However, it is not known whether the antioxidant silymarin might have a beneficial effect in extrahepatic cholestasis in common bile duct ligated rats. Malonaldehyde property concentrations, the hydrogen-donating ability and reducing power were measured in liver homogenates by spectrophotometry, as well as free SH-group levels and glutathione-reductase activities in sera. The total scavenger capacity of the livers was quantified by a chemiluminometric method. The elevated lipid peroxidation and decreased antioxidant capacity of liver homogenates and sera could be observed in ligated rats. Silymarin pretreatment improved the antioxidant capacity of the liver, diminished the direct bilirubin concentration and caused an increase of liver enzyme activities compared with the groups without treatment. These effects of silymarin suggest that it may be a useful agent for improving the antioxidant defensive system in extrahepatic cholestasis, but its choleretic property should be considered.