Interaction between vitamins C and E affects their tissue concentrations, growth, lipid oxidation, and deficiency symptoms in yellow perch (Perca flavescens)

Effects of dietary thiamin (vitamin B1) on the growth performance, serum biochemical factors, immune response, and antioxidant activity of great sturgeon (Huso huso) juveniles

The present research evaluated the positive effects of dietary thiamin (vitamin B1) levels on the growth performance, serum biochemistry factors, immune response, and antioxidant activity of great sturgeon (Huso huso) juveniles. Thiamin was included in diets with levels of 0 (control, T0), 7 (T7), 15 (T15), and 25 (T25) mg/kg diet. Measurements of thiamin levels in diets indicated that they contained 1.80 (T0), 8.02 (T7), 16.2 (T15), and 26.6 (T25) mg thiamin/kg feed. Sturgeon juveniles (240 individuals) with average weight of 44.8 ± 1.96 g were distributed into 12 tanks, and fed with the experimental diets for 8 weeks. Final weight, body weight gain (%), specific growth rate, and feed conversion ratio (FCR) of great sturgeon were significantly influenced by dietary thiamin levels, and the maximum fish performance (P < 0.05) was obtained at a level of 15 mg/kg diet. The trypsin, chymotrypsin, creatine kinase, lipase, α-amylase, and alkaline phosphatase activities were notably (P < 0.05) affected by the dietary thiamin levels. The glucose content was not significantly (P > 0.05) different among the experimental treatments. Diets supplemented with thiamine increased significantly (P < 0.05) triglyceride, cholesterol, and total protein levels accompanied with significant (P < 0.05) decreases in aminotransferase aspartate and alanine aminotransferase activities. Serum antioxidant enzymes were remarkably (P < 0.05) higher, while serum malondialdehyde was significantly (P < 0.05) lower in the thiamin-treated fish compared with the control group. Total immunoglobulin, lysozyme, and ACH50 values were significantly (P < 0.05) higher in fish fed with thiamin-supplemented diets than in the control group. The results of the present study demonstrated that dietary thiamin have an important role in enhancing the growth performance, immune response, and antioxidant activity of great sturgeon. Based on the regression fitting curve of final weight, weight gain, specific growth rate, and FCR values, the optimal level of thiamin is found to be 15.0-17.5 mg/kg diet.

Determination of tissue-specific interaction between vitamin C and vitamin E in vivo using senescence marker protein-30 knockout mice as a vitamin C synthesis deficiency model

Vitamin E (α-tocopherol; VE) is known to be regenerated from VE radicals by vitamin C (L-ascorbic acid; VC) in vitro. However, their in vivo interaction in various tissues is still unclear. Therefore, we alternatively examined the in vivo interaction of VC and VE by measurement of their concentrations in various tissues of senescence marker protein-30 (SMP30) knockout (KO) mice as a VC synthesis deficiency model. Male SMP30-KO mice were divided into four groups (VC+/VE+, VC+/VE-, VC-/VE+ and VC-/VE-), fed diets with or without 500 mg/kg VE and given water with or without 1·5 g/l VC ad libitum. Then, VC and VE concentrations in the plasma and various tissues were determined. Further, gene expression levels of transporters associated with VC and VE, such as α-tocopherol transfer protein (α-TTP) and sodium-dependent vitamin C transporters (SVCTs), were examined. These results showed that the VE levels in the VC-depleted (VC-/VE+) group were significantly lower than those in the VC+/VE+ group in the liver and heart; the VC levels in the VE-depleted (VC+/VE-) group were significantly lower than those in the VC+/VE+ group in the kidneys. The α-TTP gene expression in the liver and kidneys was decreased by VC and/or VE depletion. Moreover, SVCT1 gene expression in the liver was decreased by both VC and VE depletion. In conclusion, these results indicate that VC spares VE mainly in the liver and heart and that VE spares VC in the kidneys of SMP30-KO mice. Thus, interaction between VC and VE is likely to be tissue specific.

Dietary supplementation of vitamin C: an effective measure for protection against UV-B irradiation using fish as a model organism

The development of UV-B protective mechanisms in aquacultural species is essential for the sustainable production of healthy aqua crop. Freshwater carp Catla catla larvae (13.5 ± 1.12 mg) were fed with a diet containing 0.5% vitamin C (D1) and a control diet (D2) for 40 days. Each group was exposed to two doses of UV-B irradiation: 360 (5 min, D1_{5 min} and D2_{5 min}) and 720 mJ cm^-2 (10 min, D1_{10 min} and D2_{10 min}) for 15 days. Significantly (p < 0.05) higher survival and average weight were recorded in D1 compared to D2 exposed to the same dose. Also, significantly (p < 0.001) higher nitric oxide synthase and lower thiobarbituric acid reactive substances and heat shock protein 70 levels were recorded in D1_{5 min} compared to the other groups. A direct relationship was found between the dose of UV-B and DNA fragmentation in muscles. DNA damage indices such as tail DNA, tail extent moment and olive tail moment were significantly (p < 0.01) lower in D1_{5 min}. Thus, supplementation of vitamin C in the diet provides UV-B protection to larvae.

Effects of dietary vitamin E on growth performance as well as intestinal structure and function of channel catfish (Ictalurus punctatus, Rafinesque 1818)

To evaluate the impact of dietary vitamin E supplementation on growth performance, the intestinal structure and function of channel catfish (Ictalurus punctatus, Rafinesque 1818) was investigated. A total of 900 healthy channel catfish (weight, 5.20±0.15 g) were divided into four groups, which received experimental diets with different vitamin E content (0, 50, 100 or 1,000 mg/kg). At the end of the feeding trial (after 15 weeks), the growth and gut performance of the animals was determined. The digestive enzyme activity in hepatopancreas and gut was also detected. In addition, the height of intestinal fold, the thickness of the mucous membrane and the number of somatostatin-positive cells was examined by histological analysis. Dietary vitamin E supplementation at 50 and 100 mg/kg significantly improved the growth and gut performance, which also increased the activity of several digestive enzymes compared to that in animals without vitamin E supplementation (P<0.05). In addition, vitamin E supplementation also significantly increased the height of intestinal fold and the thickness of the mucous membrane (P<0.05). Fish with dietary vitamin E supplementation at appropriate doses also had more somatostatin-positive cells in than those without vitamin E supplementation (P<0.05). In conclusion, dietary vitamin E supplementation at 50 and 100 mg/kg was shown to improve the growth performance as well as intestinal structure and function of channel catfish.

The effects of dietary thiamin on oxidative damage and antioxidant defence of juvenile fish

The present study explored the effects of thiamin on antioxidant capacity of juvenile Jian carp (Cyprinus carpio var. Jian). In a 60-day feeding trial, a total of 1,050 juvenile Jian carp (8.20 ± 0.02 g) were fed graded levels of thiamin at 0.25, 0.48, 0.79, 1.06, 1.37, 1.63 and 2.65 mg thiamin kg(-1) diets. The results showed that malondialdehyde and protein carbonyl contents in serum, hepatopancreas, intestine and muscle were significantly decreased with increasing dietary thiamin levels (P < 0.05). Conversely, the anti-superoxide anion capacity and anti-hydroxyl radical capacity in serum, hepatopancreas, intestine and muscle were the lowest in fish fed the thiamin-unsupplemented diet. Meanwhile, the activities of catalase (CAT), glutathione peroxidase, glutathione S-transferase and glutathione reductase, and the contents of glutathione in serum, hepatopancreas, intestine and muscle were enhanced with increasing dietary thiamin levels (P < 0.05). Superoxide dismutase (SOD) activity in serum, hepatopancreas and intestine followed a similar trend as CAT (P < 0.05). However, SOD activity in muscle was not affected by dietary thiamin level (P > 0.05). The results indicated that thiamin could improve antioxidant defence and inhibit lipid peroxidation and protein oxidation of juvenile Jian carp.

Oxidative status and histological changes in sea bass larvae muscle in response to high dietary content of docosahexaenoic acid DHA

In previous studies, we observed dystrophic alterations in muscle of 48-day-old sea bass fed imbalanced docosahexaenoic acid (DHA) and vitamin E diets. To understand the whole pathological process associated with oxidative stress, a histological study was performed by feeding 14-day-old sea bass larvae with microdiets containing different ratios of DHA/vitamin E (1/150, 5/150 and 5/300) for a period of 21 days. Larvae fed diet 1/150 showed no lesions in contrast to larvae fed diets 5/150 and 5/300 where the highest incidence of muscle lesions and thiobarbituric acid reactive substances (TBARS) content was observed. Semithin sections revealed focal lesions consisting of degenerated fibres with hypercontracted myofilaments and extensive sarcoplasm vacuolization affecting both red and white muscle. Ultrathin sections of degenerating muscle fibres showed diffuse dilatation of sarcoplasmic reticulum, disorganized myofilaments and autophagic vacuoles containing myelin figures and dense bodies. Additionally, some macrophages were observed among injured fibres as numerous satellite cells. Results from the study agree with those obtained from previous work, proving the pathological potential of free radicals in sea bass larvae musculature. Moreover, high vitamin E inclusion could not completely protect cell membranes from free radicals action.

Cypermethrin-induced histopathological and biochemical changes in Nile tilapia (Oreochromis niloticus), and the protective and recuperative effect of ascorbic acid

The objective of this study was to investigate the effects of ascorbic acid on the toxicity of cypermethrin's on histopathological lesions in tissues and protein, glycogen levels in Oreochromis niloticus. Nile tilapia was exposed to 0.22 and 0.44 μg/l cypermethrin+control diet, 0.22 and 0.44 μg/l cypermethrin+ascorbic acid supplemented diet for 20 days. The fish were allowed recuperation period of 15 days in pesticide-free water and fed with ascorbic acid suplementation diet. In light microscopic investigation, histopathological lesions were observed in the gill, liver and kidney. The severity of lesions accreted depending on increased pesticide concentration and control diet. Some of the lesions were reversible or at least were less pronounced after recuperation period. Protein levels decreased in some groups after treatment period according to control groups (p<0.05). The highest depletions in liver, muscle and gill protein levels were found in 0.44 μg/l cypermethrin+ascorbic acid supplemented diet group (62.23%), in 0.22 μg/l cypermethrin+control diet group (53.12%) and in 0.44 μg/l cypermethrin+control diet group (61.87%) after 10 days, respectively. These levels increased at the end of the recuperation period. The highest depletion in liver glycogen levels was found in 0.22 μg/l cypermethrin+control diet group (50.50%) after 10 days (p<0.05). At the end of recuperation period, there was no difference between the groups (except 0.22 μg/l cypermethrin+ascorbic acid supplemented diet group) and controls. The decrease of muscle glycogen, except 0.22 μg/l cypermethrin+ascorbic acid supplemented diet group, was recorded at the end of 10 and 20 days. In the recuperation period, an increase was observed at all groups. These results revealed that the histopathology, protein and glycogen can work as good indicators of stress of a toxicant on fish. Ascorbic acid serves fish as an antitoxic agent against pesticide toxicity.

Effect of 10% Sodium Ascorbate and 10% α-tocopherol in Different Formulations on the Shear Bond Strength of Enamel and Dentin Submitted to a Home-use Bleaching Treatment

A significant reduction in bond strength of restorative materials to dentin and enamel after home-use bleaching treatment has been reported. Antioxidizing agents may be a procedure to increase bond strength values. Although no reversal of bond strength values was found for sodium ascorbate, alpha-tocopherol formulated in solution resulted in a significant increase in bond strength of bleached enamel.

Dietary ascorbic acid and alpha-tocopherol mitigates oxidative stress induced by copper in the thornfish Terapon jarbua

The protective effects of vitamins C and E against oxidative stress were evaluated in various tissues of thornfish Terapon jarbua exposed to copper. Preliminary bioassay tests performed with copper and T. jarbua revealed that 4.0, 2.5 and 1.0 mg L(-1) of copper were lethal (LC(100)), medial lethal (LC(50)) and sublethal (LC(0)) respectively. Oxidative stress parameters viz. lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase, and glutathione were evaluated in control and experimental fishes. Lipid peroxidation activity increased in tissues of copper exposed fishes, while the antioxidant system exhibited a reduction in their activity. On the contrary copper stressed fishes fed with vitamins C and E enriched pellet feed showed significant reduction in lipid peroxidation activity and the antioxidant levels increased reaching near normal levels comparable to control values. Bioaccumulation of copper was studied in addition to oxidative stress. Substantial copper residue was detected in the tissues of T. jarbua exposed to copper and the level of copper in tissues reduced when the fishes were treated with vitamins ensuring copper depuration and thereby protecting them against stress. We concluded that vitamin supplementation offered significant reduction of the oxidative stress mediated by copper and we discuss the possible application of vitamins in costal aquaculture process.

Fructose-enriched diet modifies antioxidant status and lipid metabolism in spontaneously hypertensive rats

OBJECTIVE

High-fructose consumption in industrial countries has been shown to induce metabolic abnormalities or syndrome X. Changes in antioxidant defense are unknown in hypertension associated with metabolic disorders induced by high-fructose feeding.

METHODS

Twenty spontaneously hypertensive rats were assigned to one of two groups; one received a fructose-enriched diet (60% fructose) and the other a starch diet. After a 13-wk diet period, total antioxidant status was assessed in the blood and liver by monitoring the rate of free radical-induced red blood cell hemolysis. Antioxidants (enzymes and vitamins) were determined in blood and liver. Gene expression of antioxidant enzymes (copper/zinc superoxide dismutase and glutathione peroxidase) were also investigated in hepatic tissue.

RESULTS

Fructose-fed rats showed blood pressure values similar to that of control rats but had increased glycemia and insulinemia. The antioxidant capacity in the blood of the fructose-fed group represented by copper/zinc superoxide dismutase and glutathione peroxidase activities and ascorbic acid was lower. However, the fructose diet enhanced the total antioxidant capacity of liver correlated with increased antioxidant enzyme activities and retinol concentrations. Gutathione peroxidase mRNA expression was decreased in livers of spontaneously hypertensive rats fed the fructose diet.

CONCLUSION

Fructose feeding negatively affects antioxidant capacity in the blood of hypertensive rats but improves this capacity in the liver.

Lipoic acid and ascorbic acid affect plasma free amino acids selectively in the teleost fish pacu (Piaractus mesopotamicus)

Most studies on the antioxidants, lipoic acid (LA) and ascorbic acid (AA), focused on species that, unlike teleost fish, are not scurvy-prone, and are able to synthesize AA. The antioxidant properties of LA may make it useful in aquaculture nutrition, but several effects must first be investigated, and we address here plasma free amino acids (FAA). In mammals, LA and AA in high doses were claimed to alter plasma FAA profile; to our knowledge, however, no data are available in fish. We therefore studied the effects of dietary LA and AA on plasma FAA in the South American teleost fish pacu, which is being used increasingly in aquaculture. LA treatment decreased concentrations of 18 of 23 individual FAA; specifically, dispensable and total FAA were significantly affected. Ornithine was elevated (+26%) in LA-treated fish and significantly decreased ratios of plasma [Arg]/[Orn] and other individual [FAA]/[Orn] were observed. LA and AA both affected sulfur FAA concentrations. Plasma cystine levels were significantly increased in the LA-supplemented groups. AA had little effect on most amino acids, and no interaction with LA was detected. AA supplementation did, however, significantly lower taurine (-42%) and cystathionine (-31%) levels in plasma. No effect on the branched chain:aromatic amino acid ratios was observed. The data indicate that at the dietary level studied, LA and AA independently affect selected plasma FAA in pacu, and suggest that any use of LA in particular as a dietary supplement should take into account an altered plasma FAA profile.