Vitamin E supplementation modulates gingival crevicular fluid lipid peroxidation and antioxidant levels in patients with orthodontic tooth movement

The aim of this study was to investigate the levels of the oxidant and antioxidant changes in orthodontic tooth movement and the effects of vitamin E on these parameters. For this purpose, 50 orthodontic patients (aged 13-18 years) required non-extracted treatment were divided randomly into the following groups: Control and Vitamin E. Same pre-adjusted appliances were applied to all patients, and vitamin E (300 mg day(-1)) was given during 1 month in vitamin E group. Gingival crevicular fluid was collected and periodontal indexes were recorded at the baseline and after 1 month. Lipid peroxidation (LP) levels as malonyldialdehyde, reduced glutathione (GSH) and glutathione peroxidase (GSH-Px), vitamin C and E levels were measured in the anterior and posterior regions of the dentition. After 1 month, orthodontic treatment LP levels increased in control group in both anterior and posterior regions in vitamin E group. LP levels also increased in vitamin E group in only posterior region. The level of GSH and vitamin C did not change statistically in control and vitamin E groups. Periodontal indexes did not show any differences in comparison with the groups. In conclusion, we observed protective role of vitamin E on LP levels in anterior region of patients with orthodontic tooth movement.     

Vitamin E supplementation modifies adaptive responses to training in rat skeletal muscle

Abstract

Aim of the present study was to test, by vitamin E treatment, the hypothesis that muscle adaptive responses to training are mediated by free radicals produced during the single exercise sessions. Therefore, we determined aerobic capacity of tissue homogenates and mitochondrial fractions, tissue content of mitochondrial proteins and expression of factors (PGC-1, NRF-1, and NRF-2) involved in mitochondrial biogenesis. Moreover, we determined the oxidative damage extent, antioxidant enzyme activities, and glutathione content in both tissue preparations, mitochondrial ROS production rate. Finally we tested mitochondrial ROS production rate and muscle susceptibility to oxidative stress. The metabolic adaptations to training, consisting in increased muscle oxidative capacity coupled with the proliferation of a mitochondrial population with decreased oxidative capacity, were generally prevented by antioxidant supplementation. Accordingly, the expression of the factors involved in mitochondrial biogenesis, which were increased by training, was restored to the control level by the antioxidant treatment. Even the training-induced increase in antioxidant enzyme activities, glutathione level and tissue capacity to oppose to an oxidative attach were prevented by vitamin E treatment. Our results support the idea that the stimulus for training-induced adaptive responses derives from the increased production, during the training sessions, of reactive oxygen species that stimulates the expression of PGC-1, which is involved in mitochondrial biogenesis and antioxidant enzymes expression. On the other hand, the observation that changes induced by training in some parameters are only attenuated by vitamin E treatment suggests that other signaling pathways, which are activated during exercise and impinge on PGC-1, can modify the response to the antioxidant integration.     

Radical Exchange Reactions between Vitamin E, Vitamin C and Phospholipids in Autoxidizing Polyunsaturated Lipids

Antioxidant reactions of mixtures of vitamin E, vitamin C and phospholipids in autoxidizing lipids at 90°C have been studied by ESR spectroscopy. When the phospholipid contained a tertiary amine (e.g. phosphatidylcholine), the vitamin C and the vitamin E radicals were successively observed as these two vitamins were sequentially oxidised during lipid oxidation. In the presence of the primary amine contained in phosphatidylserine, the vitamin E oxidation was delayed for a few hours. In this case neither the vitamin C, nor the vitamin E radicals but a nitroxide radical derived from the phospholipid was observed. Similar results to those obtained with PS were obtained in the presence of either phospha-tidylethanolamine or soybean lecithin. The participation in the radical reactions of phospholipids possessing a primary amine can therefore explain the synergistic effect of these phospholipids in a mixture of vitamins E and C.     

Oxidative stress and serum paraoxonase activity in experimental hypothyroidism: effect of vitamin E supplementation

Thyroid hormones are associated with the oxidative and antioxidative status of the organism. Since data on the oxidative status of hypothyroidism are limited and controversial, we investigated the oxidant and antioxidant status and serum paraoxonase/arylesterase activities in propylthiouracil-induced hypothyroidism and examined the effect of vitamin E supplementation on this experimental model. Forty male Sprague Dawley rats were randomly divided into four groups (group 1, control; group 2, control + vitamin E; group 3, propylthiouracil; group 4, propylthiouracil + vitamin E). Plasma, red blood cell, liver, heart and skeletal muscle malondialdehyde levels were increased in the propylthiouracil-treated group compared with the control rats and were decreased in propylthiouracil + vitamin E group compared with the propylthiouracil-treated group. Vitamin E supplementation also significantly increased liver and kidney reduced glutathione levels in propylthiouracil treated animals. Serum paraoxonase and arylesterase activities were decreased in propylthiouracil treated group and vitamin E supplementation caused significant increase in serum paraoxonase activity compared with the propylthiouracil-treated rats. These findings suggest that hypothyroidism is accompanied with increased oxidative stress and vitamin E supplementation exerts beneficial effects on this situation.     

Vitamin E reduces amyloidosis and improves cognitive function in Tg2576 mice following repetitive concussive brain injury

Traumatic brain injury is a well-recognized environmental risk factor for developing Alzheimer's disease. Repetitive concussive brain injury (RCBI) exacerbates brain lipid peroxidation, accelerates amyloid (Abeta) formation and deposition, as well as cognitive impairments in Tg2576 mice. This study evaluated the effects of vitamin E on these four parameters in Tg2576 mice following RCBI. Eleven-month-old mice were randomized to receive either regular chow or chow-supplemented with vitamin E for 4 weeks, and subjected to RCBI (two injuries, 24 h apart) using a modified controlled cortical impact model of closed head injury. The same dietary regimens were maintained up to 8 weeks post-injury, when the animals were killed for biochemical and immunohistochemical analyses after behavioral evaluation. Vitamin E-treated animals showed a significant increase in brain vitamin E levels and a significant decrease in brain lipid peroxidation levels. After RBCI, compared with the group on regular chow, animals receiving vitamin E did not show the increase in Abeta peptides, and had a significant attenuation of learning deficits. This study suggests that the exacerbation of brain oxidative stress following RCBI plays a mechanistic role in accelerating Alphabeta accumulation and behavioral impairments in the Tg2576 mice.     

Aging Is Associated with a Decrease in Synaptosomal Glutamate Uptake and an Increase in the Susceptibility of Synaptosomal Vitamin E to Oxidative Stress

We examined the influence of aging upon the uptake of glutamate by synaptosomes, and the oxidation of Synaptosomal vitamin E. Synaptosomes isolated from the cerebral hemispheres of Fischer 344 rats, 4 and 24 months old, were suspended at 37°C in buffer (pH 7.4) simulating extracellular fluid containing 10 mM glucose. The K_m for the high affinity uptake of tritium labeled glutamate was 10 M. The uptake of glutamate was lower in synaptosomes from older animals than those from younger animals for periods of up to 20 minutes. Upon incubation with a mixture of ferrous iron and ascorbate, more of the alpha tocopherol in synaptosomes derived from older rats was oxidized than in those derived from younger ones. Older animals may be more susceptible to excitotoxicity because: a) Synaptosomal reuptake of glutamate is less efficient and b) oxidative stress induced by various agents including glutamate may be higher in synaptosomes from the older animal.     

Levels of lipid peroxidation,nitric oxide,and antioxidant vitamins in plasma of patients with fibromyalgia

The etiology of fibromyalgia is not clearly understood. In recent years, a few studies have investigated the possible role of reactive oxygen species (ROS) in the etiology and pathogenesis of fibromyalgia. The aim of this study was to investigate plasma antioxidant vitamins, lipid peroxidation (LP), and nitric oxide (NO) levels in patients with fibromyalgia and controls. The study was performed on the blood plasma of 30 female patients and 30 age‐matched controls. After a fast of 12 h, blood samples were taken, and plasma samples were obtained for measurement of vitamins A, C, E, and β‐carotene concentrations and levels of LP and NO. Concentrations of vitamins A (p < 0.01) and E (p < 0.001) were significantly lower in patients with fibromyalgia than in controls, and LP levels were significantly (p < 0.05) higher in the plasma of the patients than in controls. Concentrations of vitamin C and β‐carotene and levels of NO did not change significantly. These results provide some evidence for a potential role of LP and fat‐soluble antioxidants in the patients with fibromyalgia. Copyright © 2009 John Wiley & Sons, Ltd.     

Severe Vitamin E deficiency exacerbates acute hyperoxic lung injury associated with increased oxidative stress and inflammation

Hyperoxia causes acute lung injury along with an increase of oxidative stress and inflammation. It was hypothesized that vitamin E deficiency might exacerbate acute hyperoxic lung injury. This study used α-tocopherol transfer protein knockout (α-TTP KO) mice fed a vitamin E-deficient diet (KO E(-) mice) as a model of severe vitamin E deficiency. Compared with wild-type (WT) mice, KO E(-) mice showed a significantly lower survival rate during hyperoxia. After 72 h of hyperoxia, KO E(-) mice had more severe histologic lung damage and higher values of the total cell count and the protein content of bronchoalveolar lavage fluid (BALF) than WT mice. IL-6 mRNA expression in lung tissue and the levels of 8-iso-prostaglandin F_2α (8-iso-PGF_2α) in both lungs and BALF were higher in KO E(-) mice than in WT mice. It was concluded that severe vitamin E deficiency exacerbates acute hyperoxic lung injury associated with increased oxidative stress or inflammation.     

Exhaled 8-isoprostane in childhood asthma

Background

In the backdrop of conflicting reports (some studies reported adverse outcomes of biomass fuel use whereas few studies reported absence of any association between adverse health effect and fuel use, may be due to presence of large number of confounding variables) on the respiratory health effects of biomass fuel use, this cross sectional survey was undertaken to understand the role of fuel use on pulmonary function.

Method

This study was conducted in a village of western India involving 369 randomly selected adult subjects (165 male and 204 female). All the subjects were interviewed and were subjected to pulmonary function test. Analysis of covariance was performed to compare the levels of different pulmonary function test parameters in relation to different fuel use taking care of the role of possible confounding factors.

Results

This study showed that biomass fuel use (especially wood) is an important factor for deterioration of pulmonary function (particularly in female). FEV₁ (p < .05), FEV₁ % (p < .01), PEFR (p < .05) and FEF_25–75 (p < .01) values were significantly lower in biomass fuel using females than nonusers. Comparison of only biomass fuel use vs. only LPG (Liquefied Petroleum Gas) use and only wood vs. only LPG use has showed that LPG is a safer fuel so far as deterioration of pulmonary function is concerned. This study observes some deterioration of pulmonary function in the male subjects also, who came from biomass fuel using families.

Conclusion

This study concluded that traditional biomass fuels like wood have adverse effects on pulmonary function.     

PMR Study on the Absolute Structure of Kanamycins and Related Compounds

The antioxidant behaviors of vitamin E and its analogues, 2, 2, 5, 7, 8-pentamethyl-6-hydroxychroman and l, 2-diacyl-sn-glycero-3-phospho-2?-(hydroxyethyl)-2?, 5?, 7?, 8?-tetramethyl-6?-hydroxychro-man, were studied in unilamellar vesicles. The two analogues scavenged aqueous radicals generated from azo compounds more efficiently than vitamin E. On the other hand, vitamin E scavenged the lipid peroxyl radicals preferentially. It is concluded that the superior antioxidant activity of vitamin E is attributed to its location suitable for breaking the chain propagation reaction.     

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.     

Effect of Vitamin E and Polyunsaturated Fatty Acids on Cryopreserved Sperm Quality in Bos taurus Bulls Under Testicular Heat Stress

Taurine bulls are highly susceptible to heat stress, leading to increased oxidative stress (OS) and impaired sperm viability. Polyunsaturated fatty acids (PUFAs) supplementation can be an alternative to improve semen quality, which also results in more sperm susceptibility to lipid peroxidation. Moreover, this deleterious effect can be exacerbated in animals affected by heat stress. Vitamin E is a key antioxidant that counteracts lipid peroxidation of sperm membrane caused by OS. Thus, combining PUFAs with vitamin E may improve sperm quality. In this context, this study aimed to evaluate the effect of interaction between PUFAs and vitamin E on sperm quality in Bos taurus bulls under testicular heat stress. Sixteen taurine bulls under testicular heat stress were randomly assigned in four groups: Control, Vitamin E, PUFA, and PUFA?+?Vitamin E. All groups lasted for 60 days. Samples were cryopreserved/thawed and analyzed for motility variables (CASA), membrane and acrosome integrity, mitochondrial activity, susceptibility to oxidative stress, DNA integrity, and sperm-binding capacity. Results showed that vitamin E had a beneficial effect on some sperm characteristics, whereas PUFA supplementation had an adverse effect when the two treatments were evaluated separately. Finally, the association between PUFAs and vitamin E did not improve sperm quality.     

Vitamin E and selenium supplementation to alleviate cold-stress-associated deterioration in egg quality and egg Yolk mineral concentrations of Japanese quails

The effects of vitamin E (dl-α-tocopheryl acetate) and selenium (Se; Na₂-SeO₃) on egg production, egg quality, and mineral content of egg yolk in Japanese quails reared under a low ambient temperature (6°C) were evaluated. Birds (n=300; 7 wk old) were randomly assigned to 12 treatment groups, 25 birds per group. The birds in a 3×2 factorial design received either three levels of vitamin E (125, 250, and 500 mg/kg diet) or two levels of selenium (0.1 or 0.2 mg/kg diet). After 2 wk on feed, six groups of the birds were maintained at 18°C (thermoneutral temperature [TN]), and the other half were acclimated over 3 d to a decreased environmental temperature of 6°C (cold stress [CS]). The performance, egg quality, and mineral content of egg yolk were not influenced by supplemental vitamin E and selenium in quails not exposed to cold stress (p≥0.09). Two hundred fifty and 500 mg vitamin E/kg diet compared with 125 mg/kg diet and higher dietary selenium inclusions (0.2 vs 0.1 mg/kg) resulted in a better body weight, egg production, and feed efficiency (p=0.01) in quails reared under CS. Similarly, egg weight, egg specific gravity, eggshell thickness, and Haugh unit were positively influenced with vitamin E (p=0.01) and selenium (p≤0.05) supplementation. Egg yolk concentrations of Zn, Fe, and Mn were higher with higher dietary vitamin E (p=0.01) and selenium (p=0.05). There was no interaction detected for parameters measured in the present study (p≥0.3). The results of the present study showed that a combination of 250 or 500 mg vitamin E and 0.2 mg selenium per kilogram of diet provides the greatest effects on performance and egg quality of Japanese quails reared under cold stress and suggest that such a supplementation can be considered as a protective management practice in Japanese quail diets to reduce the detrimental effects of cold stress.     

Selenium-vitamin E supplementation in infertile men

In order to verify the hypothesis that selenium (Se) and vitamin E (Vit E) could improve male fertility, nine oligoasthenoteratozoospermic men were supplemented for a period of 6 mo with Se and Vit E. Compared to the baseline period (presupplementation) of 4 mo, statistically significant increases were observed for Se and Vit E levels, sperm motility, percent live, and percent normal spermatozoa. These improvements are likely to be “supplementation-dependent,” since all of the parameters returned to baseline values during the posttreatment period. None of the couples reported a pregnancy during the study. The HPLC analysis conducted on the serum of one of the patients showed the existence of at least six different Se-containing peaks, whose Se content was affected by supplementation. The mechanism(s) involved in these improvements of semen parameters is presently under investigation.     

Dynamics of Vitamin E Action against LDL Oxidation

Vitamin E acts as an important antioxidant against oxidative modification of low density lipoprotein (LDL) which is accepted as an initial event in the pathogenesis of atherosclerosis. In spite of the numerous studies and reports, the action and role of vitamin E have not been fully elucidated yet. In this brief overview, the dynamics of action of vitamin E as an antioxidant have been discussed and it is emphasized that the total antioxidant potency is determined by the relative importance of many competing reactions which is determined by the reactivities and concentrations of substrates, radicals and antioxidant and by physical factors of the environment.     

Vitamin E and Hippophea rhamnoides L. extract reduce nicotine‐induced oxidative stress in rat heart

The effects of vitamin E and Hippophea rhamnoides L. extract (HRe‐1) on nicotine‐induced oxidative stress in rat heart were investigated. There were eight rats per group and supplementation period was 3 weeks. The groups were: nicotine [0.5 mg kg^?1day^?1, intraperitoneal (i.p.)]; nicotine plus vitamin E [75 mg kg^?1day^?1, intragastric (i.g.)]; nicotine plus HRe‐1 (250 mg kg^?1day^?1, i.g.); and the control group (receiving only vehicles). Nicotine increased the malondialdehyde level, which was prevented by both vitamin E and HRe‐1. Glutathione peroxidase (GPx) activity in nicotine plus vitamin E supplemented group was higher than the others. Glutathione S‐transferase (GST) activity in nicotine plus HRe‐1 supplemented group was increased compared with the control group. Catalase activity was higher in nicotine group compared with others. GPx activity in nicotine plus vitamin E supplemented group was elevated compared with the others. Total and non‐enzymatic superoxide scavenger activities in nicotine plus vitamin E supplemented group were lower than nicotine plus HRe‐1 supplemented group. Superoxide dismutase (SOD) activity was higher in nicotine plus HRe‐1 supplemented group compared with others. Glutathione reductase activity and nitric oxide level were not affected. Increased SOD and GST activities might have taken part in the prevention of nicotine‐induced oxidative stress in HRe‐1 supplemented group in rat heart. Flavonols such as quercetin, and isorahmnetin, tocopherols such as α‐tocopherol and β‐tocopherol and carotenoids such as α‐carotene and β‐carotene, reported to be present in H. rhamnoides L. extracts may be responsible for the antioxidant effects of this plant extract. Copyright © 2010 John Wiley & Sons, Ltd.     

Fenitrothion Alters Sperm Characteristics in Rats: Ameliorating Effects of Palm Oil Tocotrienol-Rich Fraction

Exposure to organophosphate insecticides such as fenitrothion (FNT) in agriculture andpublic health has been reported to affect sperm quality. Antioxidants may have a potentialto reduce spermatotoxic effects induced by organophosphate. The present study was carriedout to evaluate the effects of palm oil tocotrienol-rich fraction (TRF) in reducing thedetrimental effects occurring in spermatozoa of FNT-treated rats. Adult maleSprague-Dawley rats were divided into four equal groups: a control group and groups ofrats treated orally with palm oil TRF (200 mg/kg), FNT (20 mg/kg) and palm oil TRF (200mg/kg) combined with FNT (20 mg/kg). The sperm characteristics, DNA damage, superoxidedismutase (SOD) activity, and levels of reduced glutathione (GSH), malondialdehyde (MDA),and protein carbonyl (PC) were evaluated. Supplementation with TRF attenuated thedetrimental effects of FNT by significantly increasing the sperm counts, motility, andviability and decreased the abnormal sperm morphology. The SOD activity and GSH level weresignificantly increased, whereas the MDA and PC levels were significantly decreased in theTRF+FNT group compared with the rats receiving FNT alone. TRF significantly decreased theDNA damage in the sperm of FNT-treated rats. A significant correlation between abnormalsperm morphology and DNA damage was found in all groups. TRF showed the potential toreduce the detrimental effects occurring in spermatozoa of FNT-treated rats.     

Effect of physical restraint on oxidative stress in mice fed a selenium and vitamin E deficient diet

Physical restraint has been associated with increased oxidative damage to lipid, protein, and DNA. The purpose of this experiment was to determine whether physical restraint would further exacerbate oxidative stress in mice fed a selenium (Se) and vitamin E (VE) deficient diet. Three-week-old mice were fed a Torula yeast diet containing adequate or deficient Se and VE. Menhaden oil was added to the deficient diet to impose an additional oxidative stress. After 4 wk feeding, half the mice in each group were restrained for 5 d in well-ventilated conical tubes for 8 h daily. Mice fed the Se and VE deficient diets had increased liver thiobarbituric acid-reactive substance (TBARS) levels and decreased liver glutathione peroxidase (GPX1) activity and α-tocopherol levels. Plasma corticosterone levels were elevated in restrained mice fed the deficient diet compared to unrestrained mice fed the adequate diet. Restraint had no effect on liver TBARS or α-tocopherol levels. Liver GPX1 activity, however, was lower in restrained mice fed the adequate diet. In addition, liver superoxide dismutase (SOD) activity was lower in the restrained mice fed the adequate or deficient diet. Thus, under our conditions, Se and VE deficient diet, but not restraint, increased lipid peroxidation in mice. Restraint, however, decreased antioxidant protection in mice due to decreased activities of GPX1 and SOD enzymes.     

Vitamin E Improves the Aminotransferase Status of Patients Suffering from Viral Hepatitis C: A Randomized,Double-Blind,Placebo-Controlled Study

Vitamin E has been shown to protect against liver damage induced by oxidative stress in animal experiments. Based on our previous findings of diminished vitamin E levels in patients suffering from viral hepatitis, we treated 23 hepatitis C patients refractory to a-interferon therapy with high doses of vitamin E (2 × 400 IU RRR-α-tocopherol/day) for 12 weeks. Study design: pro-spective randomized double-blind crossover design. Clinical parameters including alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined for monitoring the disease state, in parallel vitamin E plasma levels and plasma lipids were determined. The plasma levels of the a-tocopherol were increased about 2-fold in all 23 patients. In 11 of 23 patients the clinical parameters indicative of liver damage were improved during the phase of vitamin E treatment (48% responders). ALT levels in responders were lowered by 46% and AST levels were lowered by 35% after 12 weeks of vitamin E treatment. Cessation of vitamin E treatment was followed by a rapid relapse of ALT and AST elevation, whereas retreatment led to a reproducible ALT decrease by 45% and AST decrease of 37% after a 6 months followup. Since vitamin E is non-toxic even at elevated doses ingested over extended periods, we suggest the treatment of patients refractory to α-interferon therapy suffering from hepatitis C with vitamin E as a supportive therapy.     

Vitamin E supplementation for the ruminant

Vitamin E is essential for such body functions as growth, reproduction, prevention of various diseases, and for integrity of tissues. The most significantly important result of selenium and vitamin E deficiency is tissue degeneration (e.g. white muscle disease). Vitamin E does not cross the placenta in any appreciable amounts; however, it is concentrated in colostrum. Supplemental vitamin E can greatly increase colostral tocopherol. The importance of providing colostrum rich in vitamin E is essential as both calves and lambs are born with low levels of the vitamin. Vitamin E has been shown to increase performance of feedlot cattle and to increase immune response for ruminant health, including being beneficial for mastitis control. Vitamin E given to finishing cattle at higher than National Research Council (NRC) requirements dramatically maintained the red color (oxymyoglobin) compared with the oxidized metmyoglobin of beef. It appears that supplementation of 500 IU vitamin E per head daily for 84–126 days yields tissue -tocopherol that would maintain a favorable level of oxymyoglobin in meat, thus increasing its value. Vitamin E nutritional status is commonly estimated from plasma concentration, with a high correlation between plasma and liver levels of -tocopherol. The NRC estimates for vitamin E requirements of beef cattle, dairy cattle and sheep to range from 15 to 40 mg kg⁻¹; however, higher levels will likely improve performance, and megadose levels will improve carcass quality.