Influence of diets supplemented with vitamins C and E on pirarucu (Arapaima gigas) blood parameters

This study evaluated the influence of diets supplemented with 500, 800, 1200 mg kg-1 of vitamin C (ascorbic acid or AA) and vitamin E (alpha-tocopherol or alpha-T) on the physiological responses of pirarucu fed for 2 months. Weight and mortality were not affected by dietary vitamin type or their concentrations. Significant increase (p<0.05) on the red blood cells count was obtained on treatments with 800 and 1200 mg AA kg-1 and on the hemoglobin concentration on treatment with 500 mg alpha-T kg-1 relatively to control. Mean corpuscular volume presented a significant decrease (p<0.05) on treatment with 800 and 1200 mg AA kg-1 when compared to control. Mean corpuscular hemoglobin concentration was significantly high (p<0.05) on treatment with 500 mg alpha-T kg-1. Only in vitamin C treatments, we noticed a significant increase (p<0.05) in the number of leucocytes relative to control. All fish in the vitamin-supplemented treatments, except 500 mg AA kg-1, had high total protein values compared to control. Fish treated with 800 or 1200 mg alpha-T kg-1 also showed increases in plasma glucose concentrations. Our results suggest that 800 and 1200 mg AA kg-1 are probably the most suitable concentrations for pirarucu diets, although high vitamin E diets are not necessary for quantitative leucocyte increases for this species.     

Effect of high levels of dietary vitamin C on the blood responses of matrinxã (Brycon amazonicus)

Juvenile matrinx? (Brycon amazonicus) were fed with different dietary vitamin C (ascorbic acid or AA) concentrations for 2 months in order to evaluate its effect on the physiological condition of this species. Five treatments were tested: Reference diet-RD (350 mg AA kg(-1) and 45% crude protein commercial feed); C400, C500, C600 and C800 with supplementation of 400, 500, 600 and 800 mg AA kg(-1). Fish fed 800 mg AA kg(-1) supplemented diets presented greater weight gain and survival. Hematocrit, hemoglobin concentrations and erythrocytes showed significant increase (p<0.05) in C600 and C800 relatively to the others. Total leukocyte values were significantly higher in fish fed vitamin C supplemented diets relatively to those fed RD and leukocytes count of C600 and C800 were the highest among the treatments. Monocytes were the only cells of fish defense mechanism that presented variation, and C600 and C800 presented the lowest values (P<0.05). Glucose level was significantly different relatively to RD only in C400 and the plasmatic total protein values for fish fed vitamin C supplemented diets were higher than for fish fed the RD. Fish plasmatic ions (Na(+) and Cl(-)) were significantly lower for C500, C600 and C800 relatively to C400 and RD. The physiological profile and the growth performance of matrinx? suggest that diet supplemented with 800 mg AA kg(-1) can improve its performance and increase the survival rate.     

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.     

Effects of Dietary Supplementation with Vitamin C and Vitamin E and Their Combination on Growth Performance,Some Biochemical Parameters,and Oxidative Stress Induced by Copper Toxicity in Broilers

This study investigated effects of dietary supplementation with vitamin C, vitamin E on performance, biochemical parameters, and oxidative stress induced by copper toxicity in broilers. A total of 240, 1-day-old, broilers were assigned to eight groups with three replicates of 10 chicks each. The groups were fed on the following diets: control (basal diet), vitamin C (250 mg/kg diet), vitamin E (250 mg/kg diet), vitamin C + vitamin E (250 mg/kg?+?250 mg/kg diet), and copper (300 mg/kg diet) alone or in combination with the corresponding vitamins. At the 6th week, the body weights of broilers were decreased in copper, copper + vitamin E, and copper + vitamin C + vitamin E groups compared to control. The feed conversion ratio was poor in copper group. Plasma aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase activities, iron, copper concentrations, and erythrocyte malondialdehyde were increased; plasma vitamin A and C concentrations and erythrocyte superoxide dismutase were decreased in copper group compared to control. Glutathione peroxidase, vitamin C, and iron levels were increased; aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and copper levels were decreased in copper + vitamin C group, while superoxide dismutase, glutathione peroxidase, and vitamin E concentrations were increased; aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase were decreased in copper with vitamin E group compared to copper group. The vitamin C concentrations were increased; copper, uric acid, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and malondialdehyde were decreased in copper + vitamin C + vitamin E group compared to copper group. To conclude, copper caused oxidative stress in broilers. The combination of vitamin C and vitamin E addition might alleviate the harmful effects of copper as demonstrated by decreased lipid peroxidation and hepatic enzymes.     

Oxidative status and semen characteristics of rabbit buck as affected by dietary vitamin E,C and n-3 fatty acids

The aim of this study was to investigate the effect of dietary supplementation of long chain fatty acids (C > or = 20 LCP) of the n-3 series, vitamin E and vitamin C on the antioxidant capacity of rabbit buck and on semen characteristics. Fifty male rabbits at 30 days were randomly assigned to five different diets: Control (50 mg x kg(-1) diet alpha-tocopheryl acetate), Vitamin E (200 mg x kg(-1) diet alpha-tocopheryl acetate), n-3 (2% ROPUFA oil + 50 mg x kg(-1) diet alpha-tocopheryl acetate), n-3 + E (2% ROPUFA oil + 200 mg x kg(-1) diet alpha-tocopheryl acetate) and n-3 + E C (2% ROPUFA oil + 200 mg x kg(-1) diet alpha-tocopheryl acetate + 0.5 g x L(-1) vitamin C in the drinking water). The levels of vitamins E and C and reactive oxygen metabolites (ROMs) in the blood plasma were evaluated at different ages. The antioxidant capacity and ROMs of seminal plasma, the fatty acid profile of sperm phospholipids, the semen traits and the oxidative processes during storage (24 h at + 4 degrees C) were carried out weekly for 5 wk starting from the 5th month of age. Vitamin E addition showed enough antioxidant protection only when associated with no lipid enriched diets. The n-3 supplementation modified the fatty acid profile of the spermatozoa membrane and simultaneously enhanced oxidative processes. Only the association with supranutritional levels of vitamins E and C inhibited the oxidative processes and improved the characteristics of fresh and stored rabbit semen.     

维生素E对中华鳖幼鳖生长、肝脏维生素E以及血清皮质醇含量的影响

为探讨维生素E(VE)对中华鳖(Pelodiscus sinensis)幼鳖的生长、肝脏VE和血清皮质醇的影响，通过特定生长率、高压液相色谱法和放免法，我们测定了中华鳖幼鳖的生长、肝脏VE和血清皮质醇含量。发现VE添加量为1000和5000mg／kg的两组，能明显降低中华鳖幼鳖的生长。维生素E添加量为500、1000和5000mg／kg的三组，肝脏维生素E含量明显高于对照组，VE添加量在0—1000mg／kg的范围时，肝脏VE的含量随着饲料中VE含量的增加呈指数式增加，并且在VE添加量为5000kg／kg的一组基本达到饱和。维生素E添加量为0和50mg／kg的2组，其血清皮质醇的平均值明显高于维生素E添加量为250、500、1000和5000mg／kg的4组的平均值。上述结果表明：高剂量的VE降低了中华鳖幼鳖的生长和血清皮质醇的含量；在一定剂量范围内，肝脏VE随着饲料中VE含量的增加而升高。     

The incorporation of selenium and alterations of macro- and trace element levels in individual blood cells following supplementation with sodium selenite and vitamin E

Significant alterations in the selenium content of erythrocytes, thrombocytes, and neutrophil granulocytes were observed following a daily supplementation of 200 μg Se + 100 mg vitamin E during a period of 2 months. The neutrophil granulocytes incorporated more selenium than the thrombocytes. The iron content of the thrombocytes decreased on selenium supplementation, while the opposite was noted for the neutrophil granulocytes. The glutathione peroxidase activity was not significantly changed during the period of observation.     

Effect of oral vitamin E supplementation on oxidative stress in guinea-pigs with short-term hypothermia

Effects of oral vitamin E supplementation on blood malondialdehyde (MDA), glutathione (GSH) and vitamin E levels and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) enzyme activities in acute hypothermia of guinea-pigs were investigated. Thirty male guinea pigs, weighing 500-800 g were randomly divided into one of three experimental groups: A (control, without cooling), B (hypothermic) and C (hypothermic with vitamin E supplementation). The guinea-pigs of group C received daily oral supplementation of 460 mg kg(-1) bw vitamin E for 4 days before inducing hypothermia. Twenty-four hours after the last vitamin E supplementation, the guinea-pigs of the B and C groups were cooled by immersion into cold water (10-12 degrees C), and the control guinea-pigs were immersed into water of body temperature (37 degrees C) up to the neck for 5 min without using any anaesthetic or tranquilizer. Rectal body temperatures of groups were measured and blood samples for biochemical analysis were collected immediately after the cooling. The body temperature, GSH and vitamin E levels and GSH-Px enzyme activity of hypothermic guinea-pigs were lower (p < 0.05), but SOD enzyme activity was not different (p > 0.05) from those of control animals. Although, the body temperature of hypothermic with vitamin E supplementation group was lower (p < 0.05), all other parameters of this group were not different (p > 0.05) from the controls. It was concluded that oral supplementation of vitamin E can alleviate the lipid peroxidation-induced disturbances associated with hypothermia by increasing the serum vitamin E level to normal. However, more studies are needed to prove whether this vitamin can improve quality of life during the cold seasons.     

Effect of vitamin C and E supplementation in modulating the peripheral nerve conduction following cold exposure in humans

Exposure to an extremely cold environment without proper protection leading to hypothermia is an emergency, one of the several complications of which is impairment in nerve conduction. Our previous work in the rat model has shown the beneficial effect of vitamin C in modulating the effect of hypothermia on nerve conduction. The present study aimed to evaluate the effect of vitamins C and E, administered alone or in combination, in modulating the effect of mild hypothermia on human ulnar nerve conduction. The study was carried out on 26 volunteers divided into three groups: group I received vitamin C supplementation (2000 mg/day in a single dose and 1,000 mg/day for the next 6 days), group II received vitamins C and E in combination (1,000 mg and 800 mg respectively in a single dose and 500 mg and 400 mg respectively for the next 6 days) and group III received vitamin E (800 mg in a single dose and the same for the next 6 days). The recordings were carried out before and after single and weekly supplementation in each group. There was a fall in ulnar nerve conduction velocity with a reduction in the oral temperature of 2–2.5 °C. Vitamin C administered alone and in combination with vitamin E reduced the fall in ulnar nerve conduction velocity. Prior supplementation with vitamin C and E could help ameliorate the impairment in human ulnar nerve conduction due to hypothermia.     

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.     

Effect of prepared diet and vitamins A, E and C supplementation on the reproductive performance of cage-reared bighead carp Aristichthys nobilis (Richardson)

Twenty-month-old bighead carp, Aristichthys nobilis (Richardson), were fed prepared dry diets for 20 months in cages in Laguna de Bay, Philippines, to determine the effect on reproductive performance. The experimental diets were similar in composition except for the combinations of vitamins being tested. Diet 1 was supplemented with vitamins A, E and C; diets 2, 3 and 4 each lacked one of the supplementary vitamins; and diet 5 did not include any vitamin supplementation. Bighead carp that relied solely on natural food without a prepared diet served as a control. The total of six treatments each had two replicates. Results showed that the onset of gonad maturation was 2–3 months earlier in the fish that were fed the prepared diets regardless of vitamin supplementation, when compared with the fish that were fed natural food (control) . Moreover, the prepared diets enhanced egg hatchability which was significantly higher in fish that were fed diet 1 (+ vitamins A, E and C, 80.5 ± 18.1%) and diet 3 (– vitamin E, 78.5 ± 1.1%) than in those fish that were fed natural food (control) (36.5 ± 31.3%). Mean number of 3-day-old larvae was highest in fish fed on diet 1 (34 525 ± 1732), followed closely by fish that were fed diet 3 (32 420 ± 3909). A low number of 3-day-old larvae was obtained from fish fed the natural diet (14 490 ± 4331) as well as in fish that were fed diet 2 (– vitamin A, 14 347 ± 4863), diet 4 (– vitamin C, 21 407 ± 5840) and diet 5 (– vitamin A, E and C, 12 191 ± 1439). Other criteria for reproduction such as relative fecundity, fertilization rate, and hatching rate did not differ significantly (P > 0.05) among treatments. The addition of vitamins also had no significant effects on weight gain of adult fish.     

Effect of selenium and vitamin E supplementation on lipid abnormalities in plasma, aorta, and adipose tissue of Zucker rats

Twenty-nine obese female Zucker rats (fa / fa) were fed with a laboratory chow supplemented or not with a selenium-rich yeast (Selenion), or Selenion + vitamin E, or vitamin E alone. Twelve lean female Zucker rats (Fa / Fa) of the same littermates fed with the same diet were used as control. After 32 wk of diet, obesity induced a large increase in plasma insulin and lipid levels. A significant decrease in the plasma vitamin E/triglycerides ratio (p < 0.005) and an increase in plasma thiobarbituric reactive substances (TBARS) (p < 0.005) were also observed. Plasma selenium and vitamin E increased in all supplemented rats. The plasma insulin level was decreased by selenion supplementation and the vitamin E/triglycerides ratio was completely corrected by double supplementation with Selenion + vitamin E. TBARS were also efficiently decreased in two obese groups receiving vitamin E. In plasma, adipose tissue and aorta, obesity induced an increase in palmitic acid (C16:0), a very large increase in monounsaturated fatty acids (palmitoleic acid C16:l, stearic acid C18:l) associated with a decrease in polyunsaturated n-6 fatty acids (linoleic acid C18:2 n - 6, arachidonic C20:4 n - 6). These alterations in fatty acid distribution were only partly modulated by Se and vitamin E supplements. However, in the aorta, antioxidant treatment in obese rats significantly reduced the increase in C16:0 and C16:l (p < 0.05 andp < 0.01, respectively) and the decrease in arachidonic acid (p < 0.05). These changes could be beneficial in the reduction of insulin resistance and help to protect the vascular endothelium.     

Simon metabolites of alpha-tocopherol are not formed via a rate-controlling scission of the 3'C-H bond

The major in vivo oxidation products of alpha-tocopherol, alpha-T, are the Simon metabolites, 1 and 2. For these compounds to be formed from alpha-T the polyisoprenoid tail of alpha-T must be oxidatively cleaved at the 3' carbon atom. Comparison of the levels of 2R,4'R,8'R-alpha-(3',3'-2H2)-T and 2R,4'R,8'R-alpha-[5,7-(C2H3)2]-T remaining in various tissues of rats which had been preloaded with equal quantities of these two forms of vitamin E following a change to a vitamin E-free diet has shown that there is no statistically significant difference in the rates of loss of these two deuterium-labeled alpha-T's. This demonstrates that the Simon metabolites are not formed by a rate-controlling scission of the 3'C-H bond of alpha-T.     

Effect of dietary supplementation with Suaeda maritima on blood physiology, innate immune response, and disease resistance in olive flounder against Miamiensis avidus

The effect of Suaeda maritima enriched diet on blood physiology, innate immune response, and disease resistance in olive flounder Paralichythys olivaceus against Miamiensis avidus on weeks 1, 2, and 4 was investigated. Feeding with any enriched diet and then challenging with M. avidus significantly increased white blood cells (WBC) on weeks 2 and 4; the red blood cells (RBC) significantly increased with 0.1% and 1.0% enriched diets on week 4. The hemoglobin (Hb) and hematocrit (Ht) levels significantly increased when fed with 0.1% and 1.0% supplementation diets on weeks 2 and 4. The mean corpuscular volume (MCV) did not significantly vary with any diet and time; however the mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) significantly increased with 0.1% and 1.0% supplementation diets on weeks 2 and 4. The leukocytes such as lymphocytes (Lym), monocytes (Mon), neutrophils (Neu) and biochemical parameters such as total protein (TP), glucose (GLU), and calcium (CAL) levels significantly increased in 0.1% and 1.0% supplementation diet fed groups on weeks 2 and 4. The serum lysozyme activity was significantly enhanced in 0.1% and 1.0% supplementation diet fed groups from weeks 1 to 4 when compared to the control (0% herbal extract enriched diet). The scuticocidal activity and respiratory burst activity were significantly enhanced when fish were fed with 0.1% and 1.0% supplementation diets from weeks 2 and 4. The protective effect in terms of cumulative mortality (50% and 40%) was low in groups on being fed with 0.1% and 1.0% supplemented diet. Therefore the present study suggested that 0.1% and 1.0% S. maritime-supplemented diets protect the hematological and biochemical parameters, improving the innate immunity, affording protection disease from M. avidus infection in olive flounder.     

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.     

Studies of LDL oxidation following alpha-, gamma-, or delta-tocotrienyl acetate supplementation of hypercholesterolemic humans

In vitro tocotrienols (T3s) have potent vitamin E antioxidant activity, but unlike tocopherols can inhibit cholesterol synthesis by suppressing 3-hydroxy-3-methyl-glutarylCoA (HMG-CoA) reductase. Because hypercholesterolemia is a major risk factor for coronary artery disease and oxidative modification of low-density lipoprotein (LDL) may be involved in atherogenesis, we investigated whether daily supplements of placebo, or alpha-, gamma-, or delta- (alpha-, gamma-, or delta-) tocotrienyl acetates would alter serum cholesterol or LDL oxidative resistance in hypercholesterolemics in a double-blind placebo controlled study. Subjects were randomly assigned to receive placebo (n = 13), alpha- (n = 13), gamma- (n = 12), or delta- (n = 13) tocotrienyl acetate supplements (250 mg/d). All subjects followed a low-fat diet for 4 weeks, then took supplements with dinner for the following 8 weeks while still continuing diet restrictions. Plasma alpha- and gamma-tocopherols were unchanged by supplementation. Plasma T3s were undetectable initially and always in the placebo group. Following supplementation in the respective groups plasma concentrations were: alpha-T3 0.98 +/- 0.80 micromol/l, gamma-T3 0.54 +/- 0.45 micromol/l, and delta-T3 0.09 +/- 0.07 micromol/l. Alpha-T3 increased in vitro LDL oxidative resistance (+22%, p <.001) and decreased its rate of oxidation (p <. 01). Neither serum or LDL cholesterol nor apolipoprotein B were significantly decreased by tocotrienyl acetate supplements. This study demonstrates that: (i) tocotrienyl acetate supplements are hydrolyzed, absorbed, and detectable in human plasma; (ii) tocotrienyl acetate supplements do not lower cholesterol in hypercholesterolemic subjects on low-fat diets; and (iii) alpha-T3 may be potent in decreasing LDL oxidizability.     

Effect of high‐dose vitamin C supplementation on growth,tissue ascorbic acid concentrations and physiological response to transportation stress in juvenile silver pomfret,Pampus argenteus

This study investigated the effect of high‐dose vitamin C supplementation on growth, tissue ascorbic acid concentrations and physiological response to transportation stress in juvenile silver pomfret, Pampus argenteus (initial average weight 6.2 ± 0.2 g). Three practical diets were formulated to contain 100 (control), 450 and 800 mg ascorbic acid/kg diet, respectively, supplied as l‐ascorbyl‐2‐polyphosphate. Each diet was fed to triplicate groups of fish in circular tanks (3 m ø, 1.5 m depth) (60 fish/tank) for 9 weeks. Growth did not change significantly with dietary vitamin C levels, although an improvement tendency with an increase in vitamin C supplementation was observed. Ascorbic acid concentrations in the liver and muscle of fish fed diets containing graded levels of vitamin C were positively correlated with dietary levels of this vitamin. Tissue ascorbic acid concentrations significantly increased with increasing vitamin C supplementation. After 9 weeks, the fish were subjected to transportation stress for 4 h to determine the influence of high vitamin C supplementation on the physiological response to this stressor. Serum cortisol, glucose and lactate levels significantly increased in stressed fish. Serum cortisol and glucose concentrations after stress were significantly higher in fish fed the control diet (7.91 μg L^?1 and 0.80 mm , respectively) than in the other groups. However, there were no significant differences in serum cortisol and glucose levels after stress between the 450 and 800 mg kg^?1 diets. No significant change could be found in serum lactate levels after stress among the different treatments. In conclusion, the dietary administration of high doses of vitamin C could reduce stress in silver pomfret and increase the survival of fish under stress conditions.     

Effect of dietary vitamin E on growth, muscle composition, hematological and immunological parameters of sub-yearling beluga Huso huso L

This study was designed to determine the effect of dietary vitamin E on growth, some hematological and immunological parameters and muscle proximate analysis of beluga Huso huso. Experimental fish were fed practical diets supplemented with 0, 25, 50, 100, 200 and 400 mg Dl-all-rac-α-tocopherol acetate kg diet(-1) for 8 weeks. 360 fish (mean initial weight 49.7 ± 0.1 g) were distributed into eighteen 785 L circular concrete tanks and each diet was fed to triplicate groups of fish. At the end of experiment (8 weeks), growth parameters such as final weight (FW), weight gain (WG), total length (TL), feed conversion ratio (FCR), specific growth rate (SGR), protein efficiency ratio (PER), condition factor (CF), hepatosomatic index (HSI), muscle composition, and some physiological indicators, including hematological and immunological parameters, such as hematocrit (Hct), total leukocyte count (WBC), lymphocyte, neutrophil, eosinophil and monocyte, cortisol, glucose, erythrocyte fragility, lysozyme and complement activity were determined. FW, WG, SGR, PER and CF in fish fed unsupplemented vitamin E were significantly lower than those fish fed the other five diets. However FW and PER in fish fed control diet had not significant differences with fish fed at 400 mg kg(-1). FCR were significantly higher in fish fed control diet than other groups. TL and survival rate had no significant differences among fish groups. HSI in fish fed 0 and 25 mg vitamin E kg diet(-1) were significantly lower than the other treatments. Muscle composition analysis showed no significant differences among the treatments. Erythrocyte fragility, Hct, WBC, lymphocyte, neutrophil, eosinophil and monocyte, lysozyme and complement activities were not significant. Also cortisol and glucose concentrations had not significant differences between treatments. Results indicated that vitamin E had no significantly effect on muscle proximate analysis, hematological and immunological parameters of sub-yearling beluga but has a direct effect on growth performance of beluga sturgeon and this vitamin is an essential nutrient required for normal growth in this species.     

Arachidonic and docosahexaenoic acids differentially affect the expression of fatty acyl-CoA oxidase, protein kinase C and lipid peroxidation in HepG2 cells.

Arachidonic (AA) and docosahexaenoic (DHA) acids (5-20 microM), when supplemented to human hepatoma HepG2 cells, which are depleted in these long-chain polyunsaturated fatty acids in conventional culture conditions, enhance the expression of acyl-CoA oxidase (ACOX), the first enzyme in the peroxisomal beta-oxidation cycle. DHA is effective at lower concentrations (at 5 microM) and to a greater extent (about 60% increment) than AA (about 40%) at 20 microM. Protein kinase C (PKC) appears to be involved in the activity of AA on ACOX, but not in that of DHA, since only the effect of AA is prevented by the PKC inhibitor Staurosporine, and since a remarkable elevation of the PKC activator diacylglycerol occurs only after AA supplementation. AA also induces elevation of lipoperoxides, favoured by the relative vitamin E deficiency occurring in cultured cells, and this effect, which is prevented by supplementation of the vitamin, may contribute to PKC activation.     

The effects of dietary vitamin C on growth,liver vitamin C and serum cortisol in stressed and unstressed juvenile soft-shelled turtles (Pelodiscus sinensis)

We studied the effect of dietary vitamin C on growth, liver vitamin C and serum cortisol levels in stressed and unstressed juvenile soft-shelled turtles. Turtles were fed with vitamin C supplementation at dosages of 0, 250, 500, 2500, 5,000 or 10,000 mg/kg diet for 4 weeks. Vitamin C supplementation exerted significant effects on specific growth rate and liver vitamin C concentrations. The specific growth rate peaked in the group fed at 500 mg/kg diet, while liver vitamin C levels increased with increasing dietary vitamin C levels. Serum cortisol concentrations did not differ between groups of turtles fed diets supplemented with vitamin C in the range of 0-10,000 mg/kg. After acid stress, hepatic vitamin C levels were unaffected, while serum cortisol in the control group was significantly elevated (P<0.01). The other five groups of turtles did not show significant changes in serum cortisol compared with pre-stress levels.