维生素E对青鱼幼鱼生长、免疫及抗氨氮胁迫能力的影响

以初始体质量(7.270.40) g的青鱼为研究对象, 采用维生素E(VE)有效含量分别为14.36(对照组)、25.14、37.66、62.97、113.92和210.45 mg/kg 6种等氮等能的实验饲料, 饲养青鱼幼鱼8周后, 根据生长情况选取对照组、62.97和210.45 mg/kg VE组进行24h氨氮胁迫(20 mg/L), 研究VE对青鱼幼鱼生长、免疫及抗氨氮胁迫能力的影响。结果表明: 以特定生长率为指标, 折线模型分析表明青鱼有效维生素E需要量为45.00 mg/kg。肌肉、肝脏和血清VE含量与饲料中VE含量呈明显正相关, 当饲料VE含量超过113.92 mg/kg时, 肌肉和肝脏VE含量均达到饱和。VE对鳃丝Na+/K+-ATP酶活性(NKA)和血清皮质醇(COR)无显著影响, 但随着饲料VE含量的升高, 过氧化氢酶(CAT)和总超氧化物歧化酶活性(T-SOD)呈上升趋势, 丙二醛含量(MDA)呈下降趋势。氨氮胁迫对各处理组肌肉VE含量和血清CAT活性无影响, 但肝脏VE含量均显著降低(P0.05), 且62.97和210.4 5 mg/kg VE组血清VE水平有所升高。在胁迫后, 对照组血清T-SOD、鳃丝NKA活性显著降低, 皮质醇含量显著增加(P0.05)。与对照组相比, 62.97和210.45 mg/kg VE组T-SOD、NKA活性和皮质醇含量在胁迫前后无显著变化。各处理组MDA含量在胁迫后虽均显著升高, 但210.45 mg/kg VE组在胁迫后MDA含量仍显著低于对照组(P0.05)。以上结果说明, 青鱼幼鱼获得最大生长的有效维生素E需求量为45.00 mg/kg, 且较高VE能有效提高青鱼机体免疫力, 缓解氨氮胁迫对青鱼机体的负面影响。       

Dietary flavonoids with a catechol structure increase alpha-tocopherol in rats and protect the vitamin from oxidation in vitro

To identify dietary phenolic compounds capable of improving vitamin E status, male Sprague-Dawley rats were fed for 4 weeks either a basal diet (control) with 2 g/kg cholesterol and an adequate content of vitamin E or the basal diet fortified with quercetin (Q), (-)-epicatechin (EC), or (+)-catechin (C) at concentrations of 2 g/kg. All three catechol derivatives substantially increased concentrations of alpha-tocopherol (alpha-T) in blood plasma and liver. To study potential mechanisms underlying the observed increase of alpha-T, the capacities of the flavonoids to i) protect alpha-T from oxidation in LDL exposed to peroxyl radicals, ii) reduce alpha-tocopheroxyl radicals (alpha-T (.) ) in SDS micelles, and iii) inhibit the metabolism of tocopherols in HepG2 cells were determined. All flavonoids protected alpha-T from oxidation in human LDL ex vivo and dose-dependently reduced the concentrations of alpha-T (.) . None of the test compounds affected vitamin E metabolism in the hepatocyte cultures. In conclusion, fortification of the diet of Sprague-Dawley rats with Q, EC, or C considerably improved their vitamin E status. The underlying mechanism does not appear to involve vitamin E metabolism but may involve direct quenching of free radicals or reduction of the alpha-T (.) by the flavonoids.     

The influence of dietary vitamin C and E supplementation on the physiological response of pirarucu, Arapaima gigas, in net culture

This study evaluated the efficacy of dietary vitamin C (ascorbic acid or AA), vitamin E (alpha-tocopherol or alpha-T), and C+E supplementation on the blood parameters of Arapaima gigas grown in net cages for 45 days. Four treatments were tested: control (commercial feed); C800; E500 and C+E (800+500) with supplementation of 800 mg AA kg(-1), 500 mg alpha-T kg(-1) and 800+500 mg AA+alpha-T kg(-1), respectively. Hematocrit (Ht), red blood cells (RBC), and hemoglobin concentration (Hb) (oxidative status indicators), thrombocytes and leukocytes (immunological indicators), plasma protein and glucose were evaluated. Fish fed vitamin C and C+E supplemented diets showed greater weight gain and survival. Dietary vitamin C and C+E diet supplementation resulted in increased Ht, Hb, RBC, MCHC, total leukocytes, total proteins, thrombocytes and eosinophils compared to the control and alpha-T. The alpha-tocopherol-supplemented diet reduced the number of total thrombocytes, lymphocytes and neutrophils and increased glucose and eosinophils relatively to the control. In general, leukocytes and thrombocytes were good indicators of the efficiency of vitamin on the defense mechanism of the A. gigas reared in cages. Results indicate that high alpha-T diet supplementation provides no benefit for the maintenance of the oxidative or the immunological status of A. gigas. However, it was demonstrated that high dietary AA improves A. gigas immunological status. Red blood cell indices and immune system indicators showed no synergistic effect between the vitamins after supplementing the A. gigas diet with alpha-T+AA.     

Effect of oat by-product antioxidants and vitamin E on the oxidative stability of pork from pigs fed diets supplemented with linseed oil

The aim of the experiment was to compare the antioxidative potential of an oat by-product with the effect of vitamin E on the oxidative stability of pork from pigs fed a diet enriched with linseed oil. Thirty-four crossbreed barrows were fed individually from 39 to 109 kg body weight (BW) on one of four diets: a control diet based on barley-triticale-soybean (Diet C), a diet containing an oat byproduct (Diet O), and the same diets supplemented with vitamin E (100 mg/kg diet) (Diets CE and OE, respectively). The oat by-product, comprising oat hulls and bran, was included at 10 and 20% in the grower and finisher diets, respectively. To Diets O and OE, refined rapeseed oil was added to equalise their energy content to Diets C and CE. Compared to Diets C and CE, the inclusion of the oat by-product in Diets O and OE increased the antioxidative capacity of water-soluble and lipid soluble compounds in these diets. Dietary treatment did not influence growth performance, slaughter value, longissimus dorsi (LD) muscle quality measured by nutrient contents, pH, drip loss or colour. Vitamin E supplementation increased the alpha-tocopherol concentration in serum and meat (p < 0.01), and decreased the formation of thiobarbituric acid reactive substances (TBARS) in the fresh and stored LD (p < 0.01). In addition, diets with the oat by-product increased serum alpha-tocopherol concentration (p < 0.01) and decreased the TBARS levels in the fresh and stored LD (p < 0.05), without increasing muscle alpha-tocopherol concentration. The obtained results indicate that the phenolic compounds present in oat by-products have a considerable antioxidant potential and a beneficial effect on the pig organism and oxidative stability of meat. However, dietary inclusion with the oat by-product was not as efficient as supplementation with vitamin E.     

Effects of vitamin C and vitamin E on lipid peroxidation, blood serum metabolites, and mineral concentrations of laying hens reared at high ambient temperature

This study was conducted to determine the effects of vitamin C (L-ascorbic acid) and vitamin E (alpha-tocopherol acetate) on serum concentrations of lipid peroxidation (MDA) and triiodothyronine (T3), thyroxine (T4), adrenocorticotropic hormone (ACTH), and some metabolite and mineral in laying hens reared at high ambient temperatures ranging from 25 degrees C to 35 degrees C. One hundred twenty laying hens (18 wk old; Hy-Line) were divided into 4 groups, 30 hens per group. The laying hens were fed either a basal diet (control) or the basal diet supplemented with either 250 mg of L-ascorbic acid/kg of diet (vitamin C), 250 mg of alpha-tocopherol acetate/kg of diet (vitamin E), or 250 mg of L-ascorbic acid plus 250 mg alpha-tocopherol acetate/kg of diet (combination). Separately or as a combination vitamins C and E increased serum vitamin C and vitamin E concentrations (p < 0.001) but decreased serum MDA concentration (p < 0.05). Serum concentrations of vitamin E and vitamin C were found highest but serum MDA concentration was lowest in the combination group. Supplemental vitamins C and E either separately or in a combination increased serum T3 and T4 concentrations (p < 0.05), whereas decreased serum ACTH concentration (p < 0.01). Serum glucose and cholesterol concentrations decreased, whereas serum protein concentration increased (p < 0.05) when vitamins C and E singly or together were added to the diet. Vitamin C and vitamin E supplementation resulted in an increase in serum concentrations of Ca, P, and K (p < 0.01) but a decrease in serum concentration of Na (p < 0.05). The results of the present study suggest that supplemental vitamin C and vitamin E alter serum lipid peroxidation, vitamin C, vitamin E and metabolite status, and diets supplemented with a combination of these two vitamins offer a good management practice in laying hens reared at high temperatures. In addition, the results suggest that dietary vitamin C and vitamin E act synergistically.     

Oxidative status of plasma and muscle in rabbits supplemented with dietary vitamin E

Thirty New Zealand white rabbits, mean weight 2 kg, were divided into three equal groups balanced for body weight and randomly assigned to a diet containing 60 (C), 150 (T1) or 375 (T2) mg/kg of all-rac-alpha-tocopheryl acetate. After 29 days, the animals were slaughtered. alpha-Tocopherol was assayed in muscle (longissimus dorsi) and plasma; triglycerides and cholesterol (total, high density lipoprotein, low density lipoprotein) were analysed in plasma; reactive oxygen metabolites (ROMs) were analysed in serum; and thiobarbituric acid-reactive substances (TBARS) were analysed in muscle. There were no body weight and food intake differences between the groups. The plasma vitamin E and vitamin E:lipid ratio were significantly higher in groups T1 and T2 than in C, but increases were not linearly related to dietary levels. Muscle alpha-tocopherol concentrations in the treated groups were significantly higher than in C, and linearly related (R =.67) to the vitamin E:lipid ratio. ROM and vitamin E levels in blood were inversely related (R =.74), with ROMs significantly lower in the treated groups than in C. The 60-mg/kg dose of C recommended by the National Research Council was unable to control ROM production. Lipid oxidation in muscle was significantly lower in T2 than in the other groups, and TBARS correlated significantly with muscle vitamin E (R =.61) and serum ROM (R =.73). These data suggest that vitamin E supplemented at 375 mg/kg diet can effectively control ROM production and improve muscle lipostability. ROM assay provides a useful indirect estimate of the oxidative status of muscle in vivo.     

Zinc,iron, vitamin E,and erythrocyte stability in the rat

Previous studies have shown that deficiencies of zinc and vitamin E, as well as iron excess, contribute to peroxidative damage in several tissues in vivo. The present study reports on the sensitivity of red blood cells from young rats exposed to individual or concurrent imbalances of these three nutrients. For 21 d, rats were fed diets that were either deficient or replete in zinc and with or without excess iron or replete or deficient in vitamin E. When red blood cells from these rats were incubated in vitro, erythrocyte hemolysis, lipid peroxidation (assessed by MDA production), and hemoglobin degradation (assessed by alanine release), did not significantly increase unless vitamin E had been omitted from the diet. These results imply that either adequate tightly-bound zinc exists within the zinc-deficient cell to protect it from oxidative damage, or that other antioxidant defense mechanisms (including vitamin E) present within the plasma membrane and cytosol are sufficient to protect the cell from the otherwise damaging effects of zinc deficiency and/or iron excess.     

VE对草鱼成鱼肌肉品质和抗氧化性能的影响

在VE含量为24.1 mg/kg的实用基础饲料中分别添加VE 0(对照组)、25、50、100、200 mg/kg,饲喂平均体重为(614.9±60.5)g的草鱼60d.考察VE对草鱼成鱼生长性能、肌肉品质和抗氧化性能的影响.结果表明,各组草鱼增重率分别为51.6%、53.5%、53.4%、53.5%、54.8%,饲料系数分别为2.28、2.17、2.20、2.19、2.15,饲料中添加25-200 mg/kg VE对草鱼成伍增重率、饲料系数无显著影响(P>0.05);在肌肉品质方面,饲料中添加VE对肌肉水分、粗蛋白、粗脂肪含量无显著影响(P>0.05).肌肉保鲜肉滴水损失和冷冻肉渗出损失随VE添加量的增加而降低;随饲料中VE添加量的增加,肌肉、肝脏中VE含量增加,丙二醛含量则显著降低(P<0.05),其中VE添加量为200 mr,/kg组的肌肉、肝脏VE含量较对照组增加431.0%、353.7%,丙二醛含量则下降67.2%、61.3%(P<0.01);在血清抗氧化能力方面,当VE添加量≥50 mg/kg后,草鱼血清SOD活性显著提高(P<0.05),而血清总抗氧化能力在VE添加量0-100 mg/kg各组间尤显著差异,200 mg/kgVE组的血清总抗氧化能力较对照组显著增高(P<0.05).上述研究表明,饲料中添加VE能促进草鱼生长,改善肌肉品质,增强机体抗氧化能力.以生长性能为标准,草鱼成鱼饲料(基础饲料含VE 24.1 mg/kg)中的VE添加量25 mg/kg;以肌肉品质、抗氧化能力指标为标准,草鱼成鱼饲料中的VE添加量为200 mg/kg.     

Superoxide dismutase in mouse brain, liver and heart in the presence and absence of dietary vitamin E1

Three groups of weanling mice, 8 to a group, were fed three different diets for a 12-month period. The first group was fed a basal diet deficient in vitamin E, the second group was fed the basal diet plus 30 mg/kg diet d-alpha-tocopheryl acetate and the third group, the basal diet plus 300 mg/kg diet d-alpha-tocopheryl acetate. After 12 months, superoxide dismutase activity was measured in the liver, brain and heart. The enzyme activity in the liver was found to be 10 times the activity in either the brain or the heart. Dietary alpha-tocopherol did not influence superoxide dismutase activity in any of the tissues studied.     

Effects of exogenous vitamin E supplementation on the levels of oxidants and antioxidants in chronic obstructive pulmonary disease

Oxidative stress has been recognized as a central feature of smoke induced chronic obstructive pulmonary disease (COPD). Imbalance between oxidant and antioxidant enzymes is also an established fact in these patients. But studies in regard to stable COPD patients and effect of vitamin E supplementation are lacking. Thirty patients with COPD were included in the study. Their baseline clinical examination, spirometry, plasma malondialdehyde (MDA), alpha-tocopherol and red blood cell superoxide dismutase (SOD) levels were mea sured. Twenty healthy non-smokers who were matched for age and sex served as controls. All the above parameters were repeated after 12 weeks of supplementation with 400 IU of vitamin E daily. The mean malondialdehyde levels in the patients at baseline were higher than controls (5.91 +/- 1.23 nmol/ml vs 4.55 +/- 1.51 nmol/ml, P = 0 001), so also was plasma alpha-tocopherol levels (P < 0 001), while SOD levels were lower in the patients compared to controls (1692 +/- 259 units g/Hb vs 2451 +/- 131 units g/Hb, P < 0 001). Exogenous vitamin E (400 IU per day) supplementation did not bring about any significant change in plasma alpha-tocopherol and SOD levels. The Pearson s co-efficient of correlation between the levels of MDA, vitamin E, SOD; and spirometric measurements were not significant either on day 1 or after 12 weeks of vitamin E supplementation. The present study shows that initially the plasma lipid peroxide (MDA) levels are high and antioxidants (alpha-tocopherol and SOD) are low in patients with COPD. Exogenous supplementation with vitamin E does not have any significant effect on the spirometric measurements though it brings down the levels of MDA showing attenuation of further damage. However, inclusion of larger number of patients and supple mentation with vitamin E for longer periods may throw more light on free radical injury and protective effects of antioxidants.     

Oxidative stress and antioxidant status in mouse kidney: effects of dietary lipid and vitamin E plus iron

The purpose of this study was to determine the effects of dietary fat, vitamin E, and iron on oxidative damage and antioxidant status in kidneys of mice. Sixty 1-month-old male Swiss-Webster mice were fed a basal vitamin E-deficient diet that contained either 8% fish oil + 2% corn oil or 10% lard with or without 1 g all-rac-alpha-tocopherol acetate or 0.74 g ferric citrate per kilogram of diet for 4 weeks. Significantly (P < 0.05) higher levels of lipid peroxidation products, thiobarbituric acid reactants (TBAR), and conjugated dienes were found in the kidneys of mice fed with fish oil compared with mice fed lard irrespective of vitamin E status. Mice maintained on a vitamin E-deficient diet had significantly higher renal levels of TBAR, but not conjugated dienes, than the supplemented group. Fish oil fed mice receiving vitamin E supplementation had lower levels of alpha-tocopherol than did mice in the lard fed group. Significantly higher levels of ascorbic acid were also found in the kidneys of mice fed with fish oil than were found in mice fed lard. The levels of protein carbonyls and glutathione (GSH), and activities of catalase, superoxide dismutase, selenium (Se)-GSH peroxidase, and non-Se-GSH peroxidase were not significantly altered by dietary fat or vitamin E. Dietary iron had no significant effect on any of the oxidative stress and antioxidant indices measured. The results obtained provide experimental evidence for the pro-oxidant effect of high fish oil intake in mouse kidney and suggest that dietary lipids play a key role in determining cellular susceptibility to oxidative stress.     

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

To investigate the influence and possible interactions of dietary vitamin E and C supplementation on vitamin content of both vitamins and oxidative stability of different pork tissues 40 Large White barrows from 25 kg to 106 kg were allocated to four different cereal based diets: Basal diet (B), dl-alpha-tocopherylacetate + 200 mg/kg (E), crystalline ascorbic acid + 300 mg/kg (C) or both vitamins (EC). At slaughtering samples of liver, spleen, heart, kidney, backfat outer layer, ham and M. tongissimus dorsi were obtained. Growth performance of the pigs and carcass characteristics were not influenced by feeding treatments. Dietary vitamin E supplementation had a significant effect on the vitamin E and alpha-tocopherol concentration in all investigated tissues. Backfat outer layer, liver, spleen, kidney and heart had higher vitamin E concentrations than ham and M. longissimus dorsi. Dietary vitamin C supplementation tended towards enhanced vitamin E levels except for ham samples. Therefore, some synergistic actions without dietary vitamin E supplementation between the two vitamins could be shown. The vitamin C concentration and TBARS were increased or at least equal in all tissues due to vitamin C supplementation. Dietary alpha-tocopherol supplementation resulted in lower TBARS in backfat outer layer (malondialdehyde 0.35 mg/kg in B vs. 0.28 mg/kg in E), but increased in heart and ham. When both vitamins were supplemented (EC) TBARS were lower in M. longissimus dorsi and backfat outer layer, equal in heart and higher in liver and ham compared to a single vitamin C supplementation. Rancimat induction time of backfat outer layer was 0.3 h higher in C compared to B and 0.17 h higher in EC than in E. Correlations between levels of both vitamins were positive for kidney (r = 0.169), M. longissimus dorsi (r = 0.499) and ham (r = 0.361) and negative for heart (r = -0.350). In liver and spleen no interaction could be found. In backfat outer layer vitamin E was positively correlated with rancimat induction time (r = 0.550) and negatively with TBARS (r = -0.202), but provided no evidence that dietary vitamin E supply led to better oxidative stability.     

17β-Estradiol and Vitamin E Modulates Oxidative Stress-Induced Kidney Toxicity in Diabetic Ovariectomized Rat

The aim of this study was to investigate the effects of vitamin E (alpha-tocopherol) and 17β-estradiol (E(2)) supplementation on malondialdehyde (MDA), glutathione (GSH), vitamin A, beta carotene, selenium-dependent glutathione peroxidase (GSH-Px), zinc-dependent superoxide dismutase (SOD), and copper/zinc-dependent catalase (CAT) values in the kidney of ovariectomized (OVX) diabetic rats. Forty-two female rats were randomly divided into seven equal groups as follows: group I, control; group II, OVX; group III, OVX+E(2); group IV, OVX+E(2)+alpha-tocopherol; group V, OVX+diabetic; group VI, OVX+diabetic+E(2); and group VII, OVX+diabetic+E(2)+alpha-tocopherol. E(2) (40?μg?kg(-1)/day) and alpha-tocopherol (100?μg?kg(-1)/day) were given. Bilateral ovariectomy was performed in all groups except group I. After 4?weeks, antioxidant and MDA levels in the kidney for all groups were analyzed. GSH-Px, CAT, SOD, GSH levels, vitamin A, and beta carotene levels were decreased in OVX group compared to those in the control group but MDA level was elevated via ovariectomy. However, E(2) and E(2)+alpha-tocopherol supplementations in OVX group was associated with an increase in the GSH-Px, GSH, CAT and Zn-SOD values, vitamin A, and beta carotene levels but a decrease in MDA levels in kidney. The MDA levels in the kidney of diabetic OVX rats were found higher than those in the control and OVX groups. However, GSH, GSH-Px, CAT, SOD, vitamin A, and beta carotene levels in kidney were lower in OVX diabetic rats. On the other hand, E(2) and E(2)+alpha-tocopherol supplementations to OVX diabetic rats have caused an increase in GSH-Px, CAT and SOD, GSH, vitamin A, and beta carotene levels but a decrease in MDA levels. In conclusion, the E(2) and E(2)+alpha-tocopherol supplementations to diabetic OVX and OVX rats may strengthen the antioxidant defense system by reducing lipid peroxidation, and therefore they may play a role in preventing renal disorders.     

Effect of dietary supplementation of vitamin E in partial inhibition of Russell's viper venom phospholipase A2 induced hepatocellular and microsomal membrane damage in rats.

The current investigation furnishes a good correlation between the alpha-tocopherol content of the liver and microsomes and corresponding inhibition of Russell's viper venom phospholipase A2 inflicted damage to them. Dietary supplementation of d1-alpha-tocopherol at a concentration of 100 mg and 200 mg per kg of diet displayed less damage caused by venom phospholipase A2 in sharp contrast to the vitamin E deficient rats. alpha-tocopherol due presumably to the formation of complexes with the phospholipid hydrolysis products of the membranes, plays a significant role in membrane stabilization.     

Effect of dietary fish oil, vitamin E, and probucol on renal injury in the rat

Dietary fish oil, vitamin E, and probucol have been considered in a variety of human and experimental models of kidney disease. Using subtotal nephrectomized cholesterol-fed rats as a model for progressive kidney disease, we examined the effect of 5% dietary fish oil, or a combination of 5% dietary fish oil with 500 IU vitamin E/kg diet or 1% probucol on renal injury. Three-month-old Sprague Dawley rats were fed a control diet (C group) or a cholesterol supplemented (2%) diet (Ch group) containing either fish oil (FO group) or fish oil plus vitamin E (FO+E group) or fish oil plus probucol (FO+P group). After 4 weeks of dietary treatment, the right kidney was electrocoagulated and the left kidney nephrectomized. After 8 weeks, 24-hour urine was collected before sacrifice. No effect of the dietary treatments was noted on serum creatinine, blood urea nitrogen, or proteinuria, except that proteinuria was highest in FO+P group. Rats receiving the cholesterol diets had higher serum low density lipoprotein (LDL) + very low density lipoprotein (VLDL) cholesterol (P < 0.05). In contrast, rats in the FO+P group had the lowest serum total cholesterol and LDL+VLDL cholesterol among all groups. The FO group had 26% lower kidney alpha-tocopherol concentrations than the C group. However, inclusion of vitamin E in the diet (FO+E group) increased the kidney alpha-tocopherol status to a level comparable to that in the C group, whereas inclusion of probucol in fish oil diet (FO+P group) did not improve the kidney alpha-tocopherol status. Rats fed the cholesterol diet had a 2.5-fold higher glomerular segmental sclerosis (GSS) score and 1.5-fold higher glomerular macrophage (GM) subpopulation than the C group. These effects of the cholesterol diet were ameliorated by a fish oil diet (FO group: GSS by 30%, GM by 24%). The inclusion of vitamin E in the fish oil diet (FO+E group) did not further improve the GSS score or GM subpopulation. However, inclusion of probucol in fish oil diet (FO+P group) lowered the GSS score by 73% and reduced GM subpopulation by 83% compared with the Ch group. These remarkable changes can be attributed to the powerful hypocholesterolemic activity of probucol. Our findings indicate that progression of glomerular sclerosis in the rat remnant kidney model of progressive kidney disease can be significantly modulated with fish oil treatment.     

Influence of dietary vitamins A and E on serum alpha- and gamma-tocopherols, retinol, retinyl palmitate and carotenoid concentrations in Humboldt penguins (Spheniscus humboldti)

Serum retinol, retinyl palmitate, beta-carotene, cryptoxanthin, lutein, alpha-tocopherol and gamma-tocopherol were measured in 18 captive Humboldt penguins (Spheniscus humboldti) prior to and following the removal of Columbia River (CR) smelt (Thaleichthys pacificus) from the diet. Dietary vitamin A was reduced from 59.8 to 13.5 IU g-1 (dry matter basis) when CR smelt was removed from the diet. Minimal changes were noted in dietary vitamin E. Serum samples Without-CR smelt had significantly lower circulating retinol (1.19 +/- 0.09 vs. 1.94 +/- 0.08 micrograms ml-1) and retinyl palmitate (0.033 +/- 0.012 vs. 0.105 +/- 0.004 microgram ml-1) compared to samples With-CR. The Without-CR smelt diet resulted in increased serum alpha-tocopherol from 26.4 +/- 0.94 to 39.1 +/- 3.72 micrograms ml-1. More serum samples taken Without-CR smelt had detectable levels of gamma-tocopherol than those With-CR smelt. Serum lutein was higher for the samples taken Without versus With-CR smelt. Serum cryptoxanthin did not differ. beta-Carotene was not detected. Data indicate that high levels of dietary vitamin A can affect circulating levels of retinol, retinyl palmitate and vitamin E. Thus, dietary vitamin A and the interrelationship between vitamins A and E should be considered when assessing captive penguins.     

The potential effects of antioxidant feed additives in mitigating the adverse effects of corn naturally contaminated with <Emphasis Type="Italic">Fusarium</Emphasis> mycotoxins on antioxidant systems in the intestinal mucosa,plasma, and liver in weaned pigs

Seventy-two piglets (6.0 kg BW) were randomly distributed within six different dietary treatments to evaluate the effect of deoxynivalenol (DON) and the potential of four antioxidant feed additives in mitigating the adverse effects of DON on growth performances and oxidative status. Dietary treatments were as follows: control diet 0.8 mg/kg DON; contaminated diet (DON-contaminated diet) 3.1 mg/kg DON; and four contaminated diets, each supplemented with a different antioxidant feed additive, DON + vitamins, DON + organic selenium (Se)/glutathione (GSH), DON + quercetin, and DON + COMB (vitamins + Se/GSH + quercetin from the other treatments). Although DON was the main mycotoxin in the contaminated diet, this diet also contained 1.8 mg/kg of zearalenone (ZEN). The “mycotoxin” effects therefore included the combined effect of these two mycotoxins, DON, and ZEN. The DON-ZEN ingestion did not affect growth performances, average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F ratio), but partially induced oxidative stress in weaned pigs as shown by increased malondialdehyde (MDA) content in the plasma and superoxide dismutase (SOD) activity in liver (P?<?0.05). However, no change in the activity of other antioxidant enzymes or GSH concentrations was observed in plasma and liver of piglets fed the DON-contaminated diet (P?>?0.05). Supplementation with individual antioxidant feed additive had a limited effect in weaned pigs fed DON-ZEN-contaminated diets. Combination of antioxidants (vitamins A, C, and E, quercetin, and organic Se/GSH) reduced plasma and liver MDA content and SOD activity in liver (P?<?0.05) of piglets fed DON-ZEN-contaminated diets. Furthermore, this combination also reduced MDA content in the ileum (P?<?0.05), although activity of glutathione peroxidases (GPx), SOD or catalase (CAT) in the ileum was not affected by DON-ZEN contamination or antioxidant supplements. In conclusion, DON-ZEN contamination induced oxidative stress in weaned pigs and combination of antioxidant feed additives restored partially the oxidative status. Further studies will be necessary to assess whether the effects of antioxidant feed additives on oxidative status are specific when feed is contaminated with DON-ZEN.     

Vitamin E prevents increase in oxidative damage to lipids and DNA in liver of ODS rats given total body X-ray irradiation

We examined the effects of dietary vitamin E (VE) on oxidative damage to DNA and lipids in the liver a few days after total body irradiation (TBI). ODS rats, which lack vitamin C synthesis, were fed either a low VE diet (4.3 λmg λVE/kg) or a basal VE diet (75.6 λmg λVE/kg) for 5 weeks while vitamin C was supplied in the drinking water. The VE level in the liver of the low VE group was lower and the levels of lipid peroxides were higher compared to those of the basal VE group: the relative levels in the two groups were 1:30 for VE, 18:1 for 4-hydroxynonenal (HNE), and 10:1 for hexanal (HA). The level of 8-hydroxydeoxyguanosine (8OHdG), a marker of oxidative DNA damage, did not differ between the low VE and the basal VE groups. When the rats received TBI at the dose of 3 λGy and were killed on day 6, the levels of HNE, HA and 8OHdG increased by 2.2-, 2-, and 1.5-times, respectively, in the low VE group, but TBI did not cause such increases in the basal VE group. Changes in antioxidative enzymes (glutathione peroxidase, catalase, and Cu/Zn-SOD) in the liver could not explain the different responses of the two diet groups to TBI-induced oxidative damage. The concentrations of vitamin C and glutathione in the liver did not differ between the two groups. These results suggest that dietary VE can prevent the oxidative damage to DNA and lipids in the liver which appear a few days after TBI at dose of 3 λGy.     

Effects of Dietary Selenium, Vitamin E, and Their Combination on Growth, Serum Metabolites, and Antioxidant Defense System in Skeletal Muscle of Broilers Under Heat Stress

This experiment was conducted to evaluate the effects of dietary vitamin E, selenium (Se), and a combination of the two, on the performance, serum metabolites and oxidative stability of skeletal muscle of broilers during heat stress. The broilers raised in either a thermoneutral (23.9°C constant) or heat stress (23.9°C to 37°C cycling) environment were assigned to 6 dietary treatments (0, 0.5, or 1 mg/kg Se; 125 and 250 mg/kg vitamin E; or 0.5 mg/kg Se plus 125 mg/kg vitamin E) from 1 to 49 days of age. At the end of the experiment, blood samples were collected from chicks, the chicks sacrificed, and pectoralis superficialis muscle was used for measurement of malondialdehyde (MDA) concentration and enzyme activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD). The heat-stressed chicks consumed less feed, gained less weight, and had higher feed conversion ratio when compared to thermoneutral chicks (P<0.05). Serum concentrations of iron (Fe) and zinc (Zn) were decreased by heat stress (P<0.05), whereas the serum concentrations of copper (Cu), glucose, and uric acid were significantly increased under heat stress (P<0.05). The chicks that received supplemental of vitamin E exhibited significantly higher serum concentrations of Zn (P<0.05) and significantly lower concentrations of Cu, glucose, and uric acid (P<0.05) when exposed to heat stress. Dietary Se also caused a significant decrease in serum glucose, uric acid, and Cu concentrations of heat-stressed broilers (P<0.05), but had no significant effect on Zn concentration (P>0.05). The GPx activity remained relatively constant (P>0.05), though SOD activity and MDA levels in skeletal muscle were enhanced on exposure to heat stress (P<0.05). The heat-stressed chicks that received the combined supplementary level of vitamin E and Se had the lowest concentration of MDA and the highest activity of SOD in the skeletal muscle (P<0.05). Dietary Se also caused a significant increase in enzyme activity of GPx in the skeletal muscle (P<0.05). These results indicate that the derangement of blood parameters and oxidative stability in broilers under heat stress are improved by supplemental vitamin E and Se.