The effects of some antioxidant vitamin- and trace element-supplemented diets on activities of SOD, CAT, GSH-Px and LPO levels in chicken tissues

Significance of vitamin E supplementation, dietary content of polyunsaturated fatty acids, and preslaughter stress on oxidative status in pig as reflected in cell integrity and antioxidative enzyme activities in porcine muscle

The present study investigates the combined effects of feed-induced increase in polyunsaturated fatty acids (PUFA) content and/or alpha-tocopherol content in pig muscles and preslaughter stress on cell integrity. Cell integrity was determined by plasma lactate dehydrogenase (LDH) activity, and antioxidative status of muscle was measured by activities of the antioxidative enzymes catalase, superoxide dismutase, and glutathione peroxidase. Preslaughter stress increased LDH activity, reflecting loss in cell membrane integrity independent of increased content of PUFA and/or alpha-tocopherol. However, feed-induced increase of PUFA decreased the LDH activity in plasma immediately after slaughter. Catalase activity in the muscle tissue increased as a consequence of the high-PUFA diet, which may indicate an increased demand caused by introduction of oxidative labile PUFA.

Antioxidant defense of rainbow trout (Oncorhynchus mykiss) in relation to dietary n-3 highly unsaturated fatty acids and vitamin E contents

This study examined the modulation of the antioxidant status and related physiological changes in rainbow trout Oncorhynchus mykiss under different levels of dietary n-3 highly unsaturated fatty acids (n-3 HUFA) and vitamin E. Six diets containing 0, 100 or 1000 mg alpha-tocopheryl acetate kg(-1) diet and 20% or 48% n-3 HUFA provided by normal fish oil or DHA concentrated fish oil, respectively, were fed to 100 g size fish for 15 weeks. Growth of fish fed vitamin E deficient diets under both levels of n-3 HUFA were slightly retarded, accompanied by a reduction of hematocrit values, an enlargement of liver and spleen, an elevation of lipid hydroperoxide in red blood cell and the antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase). Supplementation of vitamin E could protect the fish from these adverse effects; however the higher dose was no better compared to the moderate dose. The modulations were clearly seen in fish fed high n-3 HUFA (48%) since they were under greater oxidative stress as indicated by the markers, lipid hydroperoxide and 8-isoprostane. The increased activity of enzymes corresponds to physiological mechanisms combating the elevation of free radicals under oxidative stress and a dietary fatty acid profile-dependent moderate dose of vitamin E is all that is required to function as an effective antioxidant.

The effect of kefir on the activities of GSH-Px, GST, CAT, GSH and LPO levels in carbon tetrachloride-induced mice tissues

Functional foods including kefir have increasingly become as popular as before in the developing world. The health benefits of kefir including the antioxidative effects are still under evaluation. Vitamin E is also a well-known antioxidant. The biologically damaging effects of reactive oxygen species are controlled in vivo by a wide spectrum of antioxidant defence mechanisms. Dietary constituents of antioxidative vitamins and other nutrients may play an important role in protecting the body against oxidative damage. The study was carried out to investigate the protective effect of kefir against oxidative damage of CCl4 in mice, compared with the well-known antioxidant vitamin E. Three-week-old Swiss Albino mice, weighing 22-26 g were used for the experiment. At the end of the microbiological analysis of kefir, the averages of the total mesophilic aerobic colony counts, lactic acid bacteria, lactic streptococci, enterococci, and yeasts were found to be 1.04 x 10(9), 9.87 x 10(8), 4.38 x 10(8), 7.80 x 10(4) and 1.26 x 10(5) CFU/ml, respectively. While both vitamin E and kefir were found to have a protective effect against CCl4-induced damage, kefir was more protective. This may probably be the first study to compare the antioxidative action of kefir and vitamin E in the animal model.

Ascorbic acid, alpha-tocopherol, and oregano supplements reduce stress-induced deterioration of chicken meat quality

In order to ameliorate a negative effect of stress on meat quality characteristics, chickens were fed a diet supplemented with a combination of ascorbic acid (1,000 ppm) and alpha-tocopherol (200 ppm) or oregano (3%), which has a high content of antioxidants. Chickens were slaughtered by cervical dislocation in the stable (no stress) or after transport and electrical stunning at the slaughter plant (stress). Activities of antioxidative enzymes (catalase, superoxide dismutase, and glutathion peroxidase) in pectoralis major (PM), iliotibialis (IL), and liver were unaffected by supplementation. However, erythrocyte stability, which is a more complex model system for determining oxidative status, increased with ascorbic acid-alpha-tocopherol supplementation and tended to increase after oregano supplementation. In nonstressed birds, this improved antioxidative status was reflected in decreased TBA-reactive substances (TBARS) in PM and liver of ascorbic acid-alpha-tocopherol-supplemented chickens and likewise in liver from oregano-supplemented chickens compared to that of nonstressed control birds. However, postmortem temperature, pH, and water-holding capacity were not affected by supplementation. Drip loss from oregano-supplemented chickens showed increased protein oxidation in specific bands, but this did not relate to water-holding capacity or antioxidative status. When exposed to stress, the concentration of TBARS in the control animals increased in PM and IL. Ascorbic acid-alpha-tocopherol supplementation protected IL, and oregano supplementation protected PM from stress-induced increases in TBARS. This differential effect between muscles may indicate differences in protection mechanisms. In conclusion, ascorbic acid-alpha-tocopherol and oregano supplements to chickens protect against stress-induced increase in TBARS, in different muscles.

Investigation of antioxidant vitamins (A, E and C) and selenium levels in chickens receiving estrogen or testosterone

In the present study estrogen or testosterone was administered to broiler chickens (6 weeks old) for 5 weeks and levels of antioxidant vitamins (A, E and C) and selenium (Se) were determined. In animals who received estrogen, vitamins A, E, C and Se levels were 0.70 +/- 0.19, 11.0 +/- 2.45, 20.0 +/- 5.17 and 130.0 +/- 25.0 microg l(-1), respectively. Vitamins A, E, C and Se levels in the testosterone-administered group were found to be 0.54 +/- 0.16, 9.9 +/- 1.96, 18.0 +/- 5.18 and 100.0 +/- 18.0 microg l(-1), respectively. Vitamins A, E, C and Se levels were found to be significantly increased in the estrogen-administered group compared to the controls (p < 0.01, p < 0.01, p < 0.05, p < 0.05, respectively). Although all parameters were increased in testosterone-treated animals, only increases in vitamins A and E were found to be statistically significant (p < 0.01, p < 0.01, respectively). Based on the present findings, estrogen and testosterone show direct antioxidant effects by increasing the activities of some enzymes and they also cause an increase in antioxidant vitamin levels and hence indirectly also contribute to antioxidant capacity.

Alteration in the glutathione, glutathione peroxidase, superoxide dismutase and lipid peroxidation by ascorbic acid in the skin of mice exposed to fractionated gamma radiation

BACKGROUND

In spite of the immense therapeutic gains produced by the fractionated irradiation (IR) regimen, radiation burden on the skin increases significantly. Protection of skin might enable use of higher radiation doses for better therapeutic gains. Ascorbic acid (AA), an essential ingredient of the human diet, is known to be a free radical scavenger and radioprotective agent. This study was undertaken to evaluate the effect of ascorbic acid on the radiation-induced changes in the status of glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD) and lipid peroxidation (LPx) in the skin of mice exposed to 10, 16 and 20 Gy of fractionated gamma radiation.

METHODS

One group of the animals was administered daily with double distilled water (DDW), while the other group received 250 mg/kg b. wt. of ascorbic acid once daily, consecutively for 5, 8 or 10 days, before hemibody (below rib cage) exposure to 2 Gy/day of gamma-rays. Skin biopsies from both the groups were collected for the biochemical estimations.

RESULTS

The irradiation of animals resulted in a dose-dependent decline in the activities of superoxide dismutase, glutathione peroxidase and glutathione contents. Ascorbic acid pretreatment resulted in a significant increase in the activities of both the enzymes and glutathione in the irradiated mouse skin. Normal concentrations of glutathione could not be restored even by day 6 post-irradiation. Conversely, lipid peroxidation increased in a dose-dependent manner in both the groups reaching a peak concentration by 3 h post-irradiation, while the ascorbic acid pretreatment inhibited the radiation-induced increase in lipid peroxidation.

CONCLUSIONS

The ascorbic acid treatment arrested the decline in the activities of superoxide dismutase and glutathione peroxidase, glutathione contents and inhibited the radiation-induced lipid peroxidation in the skin of mice exposed to different doses of fractionated gamma radiation.

Apoptosis and necrosis in developing brain cells due to arsenic toxicity and protection with antioxidants

Epidemiological studies on arsenic contamination in drinking water indicated presence of arsenic in fetal tissues. Experiments on human fetal brain explants on exposure to arsenic in culture showed disturbance in lipid peroxidation, generation of nitric oxide (NO), reactive oxygen species (ROS) and apoptosis. The oxidative stress challenged by antioxidant vitamins C, E or chelator dimercaptosuccinic acid (DMSA) may reverse arsenic toxicity on neuronal development. The concept was tested with the models: (A) human fetal brain explants exposed to arsenic, 0.3 mg/l in culture for 24 h; (B) rat neonatal brain explants from 1-day-old litters exposed to 0.3 mg/l arsenic in drinking water during gestation. Rats (n=10) were given oral administration of vitamin C, 2.5 mg/kg/day, vitamin E, 148 microg/kg/day during gestation and DMSA, 50 mg/kg for 2 days at the end of gestation. (A) The arsenic induced in human fetal brain explants increase in production of NO, 20% and ROS, 25%, and decrease in DNA, 62% and protein, 54% synthesis. The morphological analyses showed growth of viable cells, neural networking vis-à-vis apoptosis on exposure to arsenic for 24 h and necrosis and loss of ground matrix on arsenic exposure for 18 days. The occurrence of two processes of apoptosis and necrosis in different neurons of same culture indicated existence of a selective cellular defense against arsenic toxicity. (B) The rats exposed to arsenic showed increased generation of NO, 25% and ROS, 22%, loss of glutathione content from 42 to 35 microg/mg protein, 40% increase in lipid peroxidation and decreased superoxide dismutase at 32%. The administration of vitamins C, E and DMSA showed partial reversal of the effects indicating possible protection from arsenic toxicity.

Chicken model for studying dietary antioxidants reveals that apple (Cox's Orange)/broccoli (Brassica oleracea L. var. italica) stabilizes erythrocytes and reduces oxidation of insoluble muscle proteins and lipids in cooked liver

A chicken model for studying the effects of antioxidants in the diet on oxidative status was set up. Chickens fed a semi-synthetic diet low in antioxidants showed a remarkable decrease in erythrocyte stability toward H(2)O(2) or 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH), but increases in catalase activity in liver, carbonyls in insoluble muscle proteins, and enhanced lipid oxidation in heat-treated liver samples compared to that of conventionally fed chickens. Thus, this chicken model proved to be more susceptible to oxidative changes than conventionally fed chickens, reflecting a low antioxidative defense. Supplementing this low antioxidant diet with 10% apple/broccoli mixture counteracted these changes, except for activity of catalase in the liver and AAPH-induced lysis of erythrocytes. Supplementation with 10% sweet corn only reduced the carbonyl content in insoluble proteins. However, neither low antioxidant diet nor vegetable supplements affected selected antioxidative enzymes or oxidative stability of lipids in heat-treated muscle tissue.