Influence of dietary vitamin E and C supplementation on vitamin E and C content and thiobarbituric acid reactive substances (TBARS) in different tissues of growing pigs

Effects of vitamin E supplementation on renal non-enzymatic antioxidants in young rats submitted to exhaustive exercise stress

BACKGROUND

Exercise stress was shown to increase oxidative stress in rats. It lacks reports of increased protection afforded by dietary antioxidant supplements against ROS production during exercise stress. We evaluated the effects of vitamin E supplementation on renal non-enzymatic antioxidants in young rats submitted to exhaustive exercise stress.

METHODS

Wistar rats were divided into three groups: 1) control group; 2) exercise stress group and; 3) exercise stress + Vitamin E group. Rats from the group 3 were treated with gavage administration of 1 mL of Vitamin E (5 mg/kg) for seven consecutive days. Animals from groups 2 and 3 were submitted to a bout of swimming exhaustive exercise stress. Kidney samples were analyzed for Thiobarbituric Acid Reactive Substances to (TBARS) by malondialdehyde (MDA), reduced glutathione (GSH) and vitamin-E levels.

RESULTS

The group treated with vitamin E and submitted to exercise stress presented the lowest levels of renal MDA (1: 0.16+0.02 mmmol/mgprot vs. 2: 0.34+0.07 mmmol/mgprot vs. 3: 0.1+0.01 mmmol/mgprot; p < 0.0001), the highest levels of renal GSH (1: 23+4 μmol/gprot vs. 2: 23+2 μmol/gprot vs. 3: 58+9 μmol/gprot; p < 0.0001) and the highest levels of renal vitamin E (1: 24+6 μM/gtissue vs. 2: 28+2 μM/gtissue vs. 3: 43+4 μM/gtissue; p < 0.001).

CONCLUSION

Vitamin E supplementation improved non-enzymatic antioxidant activity in young rats submitted to exhaustive exercise stress.

Oxidative stability in grinds from omega-3 enhanced pork

Juárez, M., Dugan, M. E. R., Larsen, I. L., Thacker, R., Rolland, D. C. and Aalhus, J. L. 2011. Oxidative stability in grinds from omega-3 enhanced pork. Can. J. Anim. Sci. 91: 623–634. In order to investigate the effect of enhancing n-3 fatty acid levels in carcasses on the retail and sensory characteristics of pork grinds, as well as the ability of increasing dietary levels of vitamin E to stabilize the increase in PUFA levels from flaxseed supplementation, 81 pigs were used in a 3×3 factorial experiment. Dietary treatments included three lengths of time (0, 3 and 6 wk) of flaxseed supplementation and three levels of vitamin E (40, 200 and 400 mg kg feed−1). α-Tocopherol tissue levels increased with dietary vitamin E supplementation (P<0.001), and fat softness (P=0.018) and total PUFA and n-3 fatty acids (P<0.001) increased with flaxseed supplementation. Most other animal performance, carcass and lean pork quality traits were not affected (P>0.05) by dietary treatments. In ground pork, the increase in TBARS after 6 d in retail was lower (P<0.001) with increasing dietary vitamin E levels. However, vitamin E had no effect (P>0.05) on the higher (P<0.001) TBARS levels observed in grinds from flaxseed fed pigs. The dietary addition of flaxseed negatively modified (P<0.05) all the sensory attributes of both cooked and reheated products. Increasing the fat content of the grinds up to 30% seemed to counteract (P>0.05) the negative effects of feeding flaxseed for 3 wk. Feeding vitamin E was not able to prevent negative effects (P<0.05) observed during retail display in grinds with either increasing fat content or higher n-3 fatty acids from dietary flaxseed. However, increasing dietary vitamin E only showed a protective effect (P<0.05) on retail appearance after long periods of ageing.

Dietary vitamin E and lipid and color stability of beef and pork: modeling of relationships

Dietary vitamin E supplementation provides a feasible option to extend the shelf life of meat. However, the costs of extra supplementation necessitate an accurate level of feeding to achieve the maximum return in product quality improvement. The current study aimed to quantify the effects of total dietary vitamin E intake on muscle α-tocopherol concentration in cattle and pigs, and to relate muscle α-tocopherol concentration to lipid oxidation and color of meat. Through computerized and manual searches, 13 studies with cattle and 10 with pigs were identified that have presented data on dietary vitamin E intake and muscle α-tocopherol concentration. Treatment means from 12 studies with beef and 14 with pork were used to evaluate the effects of muscle α-tocopherol concentration on lipid oxidation, as represented by thiobarbituric acid reactive substances in meat stored or retail displayed at chilled temperatures. With CIELAB a* (redness) values as an indicator of color development, the association between muscle α-tocopherol concentration and color could be evaluated with treatment means from 8 studies with beef and 5 with pork. Different treatments applied within studies resulted in 20 to 66 values available for the respective regression analyses. Relationships could be described effectively by different forms of the Mitscherlich model, which presented an initial value for y when x = 0, an asymptotic plateau, and the rate of change of y with increasing values of x. With the inclusion of experiment as a random effect, the relationship between total dietary vitamin E intake (x, IU/d for cattle and mg/d for pigs) and muscle α-tocopherol concentration (y, µg/g of meat) reached asymptotic plateau values at 5.71 and 4.83 µg/g of meat for cattle and pigs, respectively. The fractional accumulation rate (per total dietary vitamin E intake) of muscle α-tocopherol concentration was considerably greater in pigs (0.0130) than in cattle (0.00174). The form of the relationship between muscle α-tocopherol concentration and thiobarbituric acid reactive substances in pork was influenced by a single value, whereas muscle α-tocopherol concentrations could not be related to a* values in beef. This study presented viable models that could be applied in practice to calculate the amounts of supplemental dietary vitamin E needed to obtain the maximum profit from beef and pork.

The effect of vitamin C supplementation in healthy dogs on antioxidative capacity and immune parameters

The aim of the study was to investigate the ability of vitamin C to increase the antioxidative and immunomodulating potential in healthy dogs. Fifteen dogs were tested for the effects of orally administered vitamin E (60 mg dl-alpha tocopheryl acetate) in combination with vitamin C (0, 30 or 60 mg ascorbic acid crystalline). Three treatments (0, 30, 60 mg vitamin C) were tested in a 3 x 3 cross-over study in three periods of 36 days. Pre-prandial blood samples were taken for analysis of vitamins C, E, A, retinyl palmitate and stearate, antioxidant status [Thiobarbituric acid reactive substances (TBARS) and uric acid], biochemical and haematological analysis. Subpopulations of lymphocytes, mitogen-induced peripheral blood mononuclear cell proliferation (PBMC) and serum IgA and IgG concentrations were determined. There was a trend (p = 0.056) for an increased plasma vitamin C concentration by vitamin C supplementation. There was no evidence that dietary treatment altered neither the other plasma vitamin concentrations nor TBARS and uric acid concentrations nor the subpopulations of the lymphocytes except for the number of CD4+ lymphocytes that increased with vitamin C supplementation. There was no effect of vitamin C on serum IgA and IgG concentration. A significant time x treatment interaction was demonstrated on PBMC's to pokeweed, with an increase observed by 30 mg vitamin C supplementation but a decrease by 60 mg vitamin C supplementation. There was no clear evidence for an effect of dietary vitamin C on antioxidative capacity in healthy dogs fed a diet with vitamin E concentrations well above the recommendations. Yet, a limited number of immunological parameters were slightly affected.

Influence of supplemental magnesium, tryptophan, vitamin C, and vitamin E on stress responses of pigs to vibration

Our objectives were to investigate and compare the effects of supplemental Mg, Trp, vitamin E (vit E), and vitamin C (vit C) on stress responses of pigs undergoing transport simulation. In this study, 126 pigs (25.1 +/- 4.4 kg BW) were allocated to one of the six following treatments: 1) negative control (no supplementation); 2) positive control (i.m. injection with 0.5 mg of carazolol/20 kg BW 12 h before vibration, beta-blocker); 3) Trp (additional amount of 6 g/kg of feed for 5 d, as-fed basis); 4) Mg (3 g/L drinking water for 2 d); 5) vit E (additional amount of 150 mg/kg of feed for 21 d, as-fed basis); 6) or vit C (additional amount of 300 mg/kg of feed for 21 d, as-fed basis). Pigs were treated in groups of three, and each treatment was replicated seven times. Feed and water intake were not different among treatments. Heart rate variables (mean, peak, and minimum heart rate, ventricular ectopic beats, and ST elevation of Channels A and B) and heart rate variability were registered from the night before vibration. Pigs were subjected to vibration in a transport simulator (8 Hz, 3 m/s) for 2 h and allowed to recover for 2 h. Generally, the positive control pigs had the lowest heart rate values (mean, peak, minimum heart rate, ST elevation of Channel A; P < 0.05), whereas Mg and Trp decreased ventricular ectopic beats and ST elevation of Channel B, respectively. The effect of vit C and E as vagal stimulators was clearly visible, whereas carazolol and Mg clearly blocked the sympathetic pathways of the autonomic nervous system. During vibration, the negative control pigs lay the least, and Mg pigs the most (P < 0.05). Salivary cortisol concentrations (taken before and after vibration and after recovery) showed that vit E pigs produced the least cortisol during stress periods. Intermediary metabolites (glucose, lactate, creatine kinase, and NEFA) were analyzed in plasma from blood taken before and after vibration. At the two sampling points, the vit E and Mg pigs had the lowest NEFA concentrations (P < 0.05), and the vit E pigs also had the lowest lactate concentrations before vibration. Urine samples were collected before and after vibration to determine catecholamine concentrations; only negative control pigs had an increase (P = 0.04) in epinephrine concentration, despite large individual variation. In general, these results indicate that the supplementation of Trp, Mg, vit E, or vit C improved coping ability of pigs during vibration comparison with the negative control treatment. A muscular injection of carazolol influenced only the heart rate variables.

Hepatic and renal concentrations of vitamins E and C in lead- and ethanol-exposed rats. An assessment of their involvement in the mechanisms of peroxidative damage

The study was aimed at investigating vitamin E and vitamin C concentrations in a liver and kidney as well as their involvement in the mechanism of peroxidative action of lead (Pb) and ethanol (EtOH) in these organs in rats receiving 500 mg Pb/l (in drinking water) or/and 5 g EtOH/kg body wt./24h (p.o.) for 12 weeks. The exposure to Pb and EtOH alone and in combination led to a decrease in vitamin E concentration in the liver compared to the control group (by 30%, 26% and 50%, respectively). The decrease in the liver vitamin E concentration in the rats co-exposed to Pb and EtOH was more marked than in those separately treated with these xenobiotics. The treatment with Pb alone and in combination with EtOH led to a decrease in vitamin E concentration in the kidney (by 13% and 21%, respectively). The liver vitamin C concentration decreased as a result of exposure to EtOH, both separately (by 17%) and in combination with Pb (by 11%). The kidney vitamin C concentration increased in the rats exposed to EtOH alone (by 10%), whereas in those treated with Pb, both separately and in combination with EtOH it decreased (by 26% and 6%, respectively). ANOVA/MANOVA analysis revealed that the changes in vitamin E concentration in the liver and kidney at co-exposure to Pb and EtOH resulted from their independent action, whereas those in vitamin C were due to an independent action of these xenobiotics (EtOH in the liver, Pb and EtOH in the kidney) and an interaction between them. There was no correlation between vitamins E and C concentrations in the liver and kidney. The liver concentration of vitamin E and the liver and kidney concentration of vitamin C negatively correlated with malondialdehyde concentration (MDA, lipid peroxidation index) in these organs. Based on the results of the present study and our previous findings in this experimental rat model it can be hypothesized that vitamins E and C are involved in the mechanism of peroxidative action of Pb and EtOH in the liver and kidney, both at separate and combined exposure. The probable protective involvement of vitamins E and C in the damaging action of EtOH and Pb may be related to scavenging of free radicals directly and indirectly generated by these xenobiotics.