Vida Rezar

The comparison of black currant juice and vitamin E for the prevention of oxidative stress.

Black currant is known as a fruit with a very strong in vitro antioxidative capacity, but its in vivo antioxidant efficacy has not yet been characterized. The aim of the experiment was to determine the potency of black currant juice in comparison to vitamin E, for decreasing oxidative stress. Oxidative stress was induced by high intake of polyunsaturated fatty acids (PUFAs) in pigs as a model for humans. Twenty-four growing pigs were divided into four groups. All groups received isocaloric daily rations composed of an equal amount of basal diet that was supplemented with starch (CONT), linseed oil (OIL), linseed oil and black currant juice (OIL+BCJ), or linseed oil and vitamin E (OIL+VIT E). The experiment confirmed that the high proportion of PUFAs in the OIL group increased oxidative stress. In comparison with the OIL group, vitamin E supplementation significantly lowered plasma malondiadehyde (MDA) and the 24-hour urine MDA excretion rate, and reduced the degree of DNA damage in leukocytes to the level of the CONT group. The black currant juice intake failed to significantly decrease plasma MDA and 24-hour urine MDA excretion rate, but did reduce the degree of DNA damage in leukocytes to the level of the CONT group, as well as increase plasma beta+gamma-tocopherol concentrations. Although black currant juice did not reduce the formation of MDA, it efficiently prevented DNA damage induced by the high intake of PUFAs. It could be concluded that under these experimental conditions vitamin E was more efficient as an antioxidant that black currant juice.

Relevance of Meat Fat Content and Fruit and Vegetable Intake for the Oxidative Status of Pigs

Background: The aim of the present study was to evaluate the effect of substituting lean meat with fat meat on oxidative stress in a diet with or without fruit and vegetables. Methods: Thirty-two pigs were divided into groups and fed isocaloric daily rations: LM+FV (balanced diet with lean meat and fruit and vegetables); FM+FV (as LM+FV, but lean meat was substituted with fat meat); LM–FV (as LM+FV, but without fruit and vegetables), and FM–FV (as FM+FV, but without fruit and vegetables). Oxidative stress was evaluated by measuring the 24-hour urine malondialdehyde excretion rate, the degree of leukocyte nuclear DNA damage, the concentration of tocopherols in blood plasma, erythrocyte glutathione peroxidase activity and the total antioxidant status of plasma. Results: The substitution of lean meat with fat meat modestly increased the rate of leukocyte DNA damage only in the diet with fruit and vegetables but had no effect in the group deprived of fruit and vegetables. Regardless of the fruit and vegetable content of the diet, the substitution of lean meat with fat meat did not affect any other parameters measured. In comparison to both fruit- and vegetable-containing diets, the deprivation of fruits and vegetables in the LM–FV and FM–FV groups significantly increased the rate of leukocyte DNA damage and reduced the plasma α-tocopherol level (significant only for FM+FV). Conclusion: The substitution of fat meat with lean meat in a diet with or without fruit and vegetables has only a marginal or no effect on oxidative stress. But fruit and vegetable exclusion markedly increased the level of oxidative stress.

Effects of supplementation with α-tocopherol, ascorbic acid, selenium, or their combination in linseed oil-enriched diets on the oxidative status in broilers

&NA; A trial was conducted to investigate whether, and if so to what extent, the combined supplementation of vitamin E, vitamin C, and selenium was superior to their sole supplementation concerning the oxidative stress induced by a high n‐3 dietary polyunsaturated fatty acids (PUFA) intake in broilers. Four hundred 21‐day‐old Ross 308 male broilers were allocated to 5 experimental groups fed the following linseed oil (5%)‐enriched finisher diets: Cont (no supplement), +E (200 IU vitamin E/kg feed), +C (250 mg vitamin C/kg feed), +Se (0.2 mg selenium/kg feed), or +ECSe (concentrations as in the sole supplementation, combined). Analyses of malondialdehyde (MDA), vitamin C, and &agr;‐ and &ggr;‐tocopherols in plasma, antioxidant capacity of water‐ (ACW) and lipid‐ (ACL) soluble compounds in serum, and glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in whole blood were performed. In breast muscle, analyses of MDA, &agr;‐ and &ggr;‐tocopherols, ACW, selenium, and fatty acid (FA) composition were carried out. Birds fed the combination of antioxidants showed reduced average daily gain (ADG) and average daily feed intake (ADFI) and, as +E, lower MDA and &ggr;‐tocopherol, together with raised &agr;‐ tocopherol levels in plasma and lower MDA and raised &agr;‐ tocopherol levels in breast muscle compared to the control. The combination of antioxidants in the +ECSe group raised GPx activity in whole blood compared to the control. In conclusion, results indicated that vitamin E is the most effective antioxidant to alleviate oxidative stress caused by high dietary PUFA and that the supplementation with additional vitamin C and selenium did not have clear synergistic effect.

Supplementing entire male pig diet with hydrolysable tannins: Effect on carcass traits, meat quality and oxidative stability

The purpose of the present study was to investigate the potential impact on carcass and meat quality of a sweet chestnut wood extract (SCWE)diet supplement for pigs, in particular on oxidative stability and fatty acid composition. Entire (non-castrated) male pigs (n=24) were assigned to treatment groups within litter and offered one of 4 finisher diets on an ad libitum basis: T0 (control), T1, T2 or T3, supplemented with 0, 1, 2 or 3% of commercially available SCWE, respectively. The highest SCWE supplementation reduced carcass fat deposition and water holding capacity of meat (higher thawing loss). In fresh meat, SCWE supplementation increased lipid (malondialdehyde) and protein oxidation (carbonyl groups in myofibril isolates). With regard to fat tissue, SCWE supplementation increased the proportion of polyunsaturated fatty acids.

Markers of oxidative stress in dogs with heart failure

We tested the hypothesis that indirect measures of oxidative stress (vitamin E, glutathione peroxidase, and malondialdehyde) differ in dogs in heart failure resulting from either myxomatous mitral valve disease or dilated cardiomyopathy. Dogs were classified according to the International Small Animal Cardiac Health Council (ISACHC) classification. Additionally, the effect of cardiac therapy on oxidative stress parameters and N-terminal pro–B-type natriuretic peptide (NT-proBNP) in advanced stages of congestive heart failure was investigated. There were no significant differences in oxidative stress parameters between healthy dogs and the individual groups of cardiac patients. Significantly lower malondialdehyde (MDA) was observed in the ISACHC II group in comparison to ISACHC groups III and I. A significant positive correlation in treated patients was observed between NT-proBNP and MDA, NT-proBNP and vitamin E, as well as between MDA and vitamin E (and lipid-standardized vitamin E). No significant differences in any of the measured parameters were found between treated and non-treated cardiac patients. Our results suggest an association between MDA (the extent of lipid peroxidation) and NT-proBNP, vitamin E and NT-proBNP, as well as between MDA and vitamin E in treated canine patients. Plasma vitamin E concentration was maintained in all stages of cardiovascular disease in these canine patients.

Effects of Olive Leaf and Marigold Extracts on the Utilization of Nutrients and on Bone Mineralization using Two Different Oil Sources in Broilers

The aim of this study was to investigate the effects of olive leaf and marigold extracts on the apparent total tract digestibility (ATTD) of the principal nutrients and energy, as well as on mineral utilization (Ca, P, Mg, Mn, Fe, Cu and Zn) in relation to bone characteristics in broilers fed walnut- or linseed oil-supplemented diets. Thirty-six 12-day-old commercial broilers Ross 308 were reared in metabolic cages, assigned to one of the six dietary treatments (3 × 2 factorial design): three supplements (not supplemented, olive leaf extract, or marigold extract), and two oils (walnut or linseed oil). The results showed that the marigold extract reduced Zn and P balances and tended to lower the balance of ash and Mg, and the ATTD of Zn and Mg. Diets with linseed oil increased the ATTD of acid detergent fiber and reduced the ATTD of the organic residue and Cu. No differences in the bone characteristics of tibia were observed between treatments. These results indicated that the inclusion of marigold extract had a negative effect on the Zn and P balance, and that neither extract had any major effect on the digestion and utilization of energy and other investigated nutrients, or on bone mineralization, irrespective of the oil source included in the diet.