Vitamin E supplementation does not mitigate the acute morbidity effects of porcine reproductive and respiratory syndrome virus in nursery pigs

The objective of this study was to determine whether feeding a vitamin E-rich diet would benefit nursery pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV). Sixty-four pigs were subjected to one of four treatment combinations (2 x 2 factorial) of dietary vitamin E (adequate or excess) and PRRSV (medium or inoculation with VR-2385 isolate P-129). Pigs were fed experimental diets during a 3-wk period before inoculation as well as during a 12-d period after inoculation. Growth performance was determined throughout the study, and lipid peroxidation in liver, glutathione peroxidase (GPX) activity in serum, circulating white blood cells, and serum interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) were determined in samples collected from pigs killed 4 or 12 d after inoculation. Infection by PRRSV (P < 0.001) induced a marked decrease in both ADFI and ADG, but neither the main effect of diet nor the diet x PRRSV interaction was significant. Neither diet nor PRRSV affected feed efficiency. At 12 d after inoculation, lipid peroxidation in liver and GPX activity in serum were lower in pigs fed excess vitamin E than in those fed adequate vitamin E (P < 0.01), suggesting that the diet high in vitamin E bolstered the antioxidant status of the pigs. However, PRRSV did not affect lipid peroxidation in liver or serum GPX activity, and the diet x PRRSV interaction was not significant. White blood cell counts were decreased and IFN-gamma, and IL-1beta were increased (P < 0.05) 4 and 12 d after inoculation in PRRSV-infected pigs, but neither diet nor the diet x PRRSV interaction was significant. Collectively, these results indicate that increasing antioxidant defenses by feeding high levels of vitamin E did not ameliorate the effects of PRRSV on decreased growth, leukopenia, and increased serum IL-1beta and IFN-gamma. Thus, feeding nursery pigs a diet high in vitamin E may not be useful for mitigating the acute morbidity effects of PRRSV infection.     

Effects of storage conditions and hemolysis on vitamin E concentrations in porcine serum and liver.

Vitamin E (alpha-tocopherol) is an antioxidant vitamin important in protecting unsaturated fatty acids in lipid membranes from peroxidation. Variation in collection, storage, and shipping conditions of samples can potentially lead to breakdown of vitamin E prior to analysis. Therefore, the purposes of this project were 1) to determine the stability of vitamin E in refrigerated and frozen porcine liver and serum and 2) to evaluate the effects of red blood cell (RBC) hemolysis on porcine serum vitamin E concentrations. Porcine liver and nonhemolyzed serum were collected and stored refrigerated or frozen. Samples were analyzed for vitamin E immediately or on days 2, 3, 7, or 14. In addition, porcine RBCs were added to normal serum at concentrations from 1 x 10(6) to 1 X 10(9) RBC/ml and hemolyzed by freeze-thaw prior to analysis for vitamin E or products of lipid peroxidation.     

牛病毒性腹泻病毒对新西兰白兔致病性分析及E2蛋白免疫效果的评价

【目的】 研究牛病毒性腹泻病毒（BVDV）感染对新西兰白兔的致病性以及BVDV E2重组蛋白的免疫效果。【方法】 将实验室培养保存的BVDV病毒纯化并按照Reed-Muench法测定其病毒滴度。在致病性试验中,将10只新西兰白兔随机分为感染组和对照组,每组5只。感染组用1 mL纯化的BVDV病毒攻毒（滴鼻500 μL、耳缘静脉注射500 μL）,对照组用等体积的生理盐水处理,连续3 d,每天1次,每天观察各组兔的临床症状并测量体温;分别于接种病毒后第6、9、12、15、17天通过耳缘静脉采集血液检测血常规;感染病毒第17天采集鼻拭子进行RT-PCR鉴定,采集后剖杀并采集气管、肺脏、脾脏和小肠组织,制备病理切片观察病理变化。在免疫效果评价试验中,将10只新西兰白兔随机分为免疫组和对照组,每组5只,免疫组用E2重组蛋白（1 mg/只）与佐剂混合后经肌内多点注射免疫新西兰白兔,对照组接种等体积生理盐水;共免疫2次,2次免疫间隔为14 d。在一免后0、7、14、21、28 d采集血清,通过间接ELISA方法检测血清中抗重组蛋白特异性抗体水平;在一免后第28天按致病性试验中方法攻毒,在攻毒第17天采集鼻拭子进行RT-PCR鉴定,采集气管、肺脏、脾脏和小肠组织制备病理切片观察病理变化及免疫组织化学检测。【结果】 纯化后BVDV的病毒滴度为4.16×10⁶ TCID₅₀/mL。与对照组相比,感染组部分新西兰白兔6 d内活动减少,采食略微减少,6 d后逐渐恢复正常,在感染第13天出现腹泻症状,从第5天开始体温略微升高,但均在正常范围内波动。与对照组相比,在攻毒第6和9天,感染组白细胞和血小板分别显著和极显著降低（P<0.05;P<0.01）;在攻毒第12、15和17天,感染组白细胞、血小板和淋巴细胞均极显著降低（P<0.01）。鼻拭子RT-PCR检测为阳性,气管、肺脏、脾脏及小肠组织表现出轻度至重度的组织病理学变化。间接ELISA检测结果表明,在一免后7 d时,血清抗体滴度为1：16~1：32;在一免后28 d时,血清抗体滴度为1：256~1：512;免疫攻毒组新西兰白兔鼻拭子经RT-PCR检测为阴性;组织病理学观察显示,免疫攻毒组气管及肺脏表现出轻微的组织病理学变化。免疫组化检测结果显示,免疫组结果均呈阴性,对照组结果均为阳性。【结论】 通过滴鼻及耳缘静脉注射BVDV的方式可以构建新西兰白兔致病模型,BVDV E2亚单位疫苗能够刺激机体产生特异性抗体,起到免疫防御的作用。     

Immunostimulation in mice infected with Sendai virus

The effect of Sendai virus infection on the splenic primary plaque-forming cell (PFC) response to sheep RBC in 2 strains of mice, with contrasting susceptibility to Sendai viral pneumonia, was examined. Mice were given single inoculations of sheep RBC, which varied relative to time of inoculation with Sendai virus, PFC were counted 6 days later, and were compared with PFC responses from noninfected mice. The IgM- and IgG-PFC responses were augmented in resistant C57BL/6J mice 7 and 9 days after inoculation with Sendai virus (sheep RBC given 1 and 3 days after inoculation with Sendai virus, respectively) and in susceptible DBA/2J mice 7, 9, 10, and 13 days after inoculation with Sendai virus. Augmentation was restricted mainly to IgM-, IgG3-, and IgG2b-PFC. The number of splenic background antitrinitrophenyl sheep RBC PFC in mice of both strains was examined during the course of Sendai virus infection. Only a marginal increase in background PFC was seen in C57BL/6J mice on or after viral inoculation day 11 and no change was seen in DBA/2J mice. Serum of infected mice also was examined sequentially for alpha/beta interferon (IFN). Despite vigorous lung IFN production, infected mice rarely had detectable circulating IFN. Seemingly, Sendai virus infection can induce transient hyperresponsiveness to a nonviral antigen.     

Effect of dietary supplementation with vitamins E and C on production performance, immune responses and antioxidant status of White Leghorn layers under tropical summer conditions

1. The effects of vitamin E (DL-alpha-tocopheryl acetate) and vitamin C (ascorbic acid) supplementation on performance, some immune variables and antioxidant status of White Leghorn layers (aged 44-56 weeks) exposed to tropical summer conditions were investigated. 2. Both vitamins E and C significantly improved the egg production, food conversion efficiency, antibody responses to inoculated sheep red blood cells (SRBC) and Newcastle disease virus (NDV) vaccine, lymphocyte proliferation in response to mitogen and activities of antioxidant enzymes red blood cell catalase (RBCC) and glutathione peroxidase (GSH-PX) in layers. Vitamin C increased the inflammatory response to phytohaemagglutinin-P (PHA-P) inoculation. 3. Supplemental vitamin C at 200 mg/kg diet significantly increased eggshell weight, eggshell thickness, and shell breaking strength. However, no effect of supplemental vitamin E on eggshell quality was observed. 4. Vitamins E and C, as well as interactions between them, significantly influenced the activities of glutathione reductase and lipid peroxidase. A combination of vitamin E at 125 IU/kg with vitamin C at 200 mg/kg diet had an additive effect on reducing the activity of oxidative enzyme lipid peroxidase (LP) and increasing the activity of antioxidant enzyme glutathione reductase (GSHR). 5. It is concluded that vitamin E (125 IU/kg) and vitamin C (200 mg/kg) could independently alleviate the effects of heat stress on production performance and immunological variables of layers. However, combination of both the vitamins at the above-mentioned concentrations is beneficial in eliciting higher antioxidant status in laying hens exposed to tropical summer conditions.     

Vitamin A deficiency impairs cytotoxic T lymphocyte activity in Newcastle disease virus-infected chickens

The effect of vitamin A deficiency on cytotoxic T lymphocyte (CTL) activity was investigated during the acute phase of disease 7 days after primary inoculation and 1 day after secondary inoculation in chickens with or without Newcastle disease virus (NDV, La Sota strain) infection. Day-old chickens with limited vitamin A reserves were fed purified diets containing either marginal (ad libitum) or adequate (pair-fed) levels of vitamin A, and at 3 weeks of age half of the chickens in each group were infected with NDV. Cytotoxic activity was investigated during the acute phase of disease (7 days after primary inoculation) and 1 day after secondary inoculation, in an assay system with either peripheral blood lymphocytes (PBL) or nonadherent splenocytes as effector cells and adherent splenocytes from the same animal as target cells. After primary inoculation, cytotoxic activity could only be demonstrated in nonadherent splenocytes. Vitamin A deficiency resulted in significantly reduced CTL activity at all effector/target cell ratios tested. After reinfection CTL activity could also be demonstrated in PBL, but only from chickens fed the control diet, suggesting a diminished pool of CTL in vitamin A deficiency. The results of this study indicate that vitamin A deficiency impairs CTL activity - a part of the cell-mediated defense system - and this may have important implications for recovery from viral infection.     

Effect of Dietary and Injectable Vitamin E on the Antioxidant Status of Pigs

An experiment concerning 6 different vitamin E treatments was conducted with 30 young pigs. From 4 to 15 weeks of age the pigs were kept in individual pens and fed a selenium supplemented basal diet consisting mostly of propionic acid treated barley and soybean meal, and containing 4.4 mg vitamin E per kg. The treatments were periods with or without vitamin E supplement (20 mg/kg) or a vitamin E injection (200 mg). Blood samples collected during the period of investigation were examined for vitamin E and for resistance against erythrocyte lipid peroxidation (ELP) in order to evaluate the antioxidant status.Analysis of variance showed a litter effect on ELP values at all the weekly investigations and a treatment effect from two weeks after the experiment had started. Also the blood vitamin E level was litter dependent and influenced by treatment. Paired comparisons by Student’s t-test showed a delay of 1 to 2 weeks in the effect on ELP of a dietary vitamin E supplement. In contrast, both ELP and vitamin E changed very rapidly (hours) after vitamin E injections.Independently of the vitamin E treatments there was a rise in ELP within the first 2 or 3 weeks after weaning; this was taken as an index of a reduced antioxidant status during that period.Key words: Vitamin E, antioxidant status, erythrocyte lipid peroxidation, pigs     

Sequential mitogen stimulation of peripheral blood lymphocytes from chickens inoculated with infectious bursal disease virus

Chickens were inoculated wih the pathogenic Edgar strain of infectious bursal disease virus at 1 week, 2 weeks, or 1 day of age. In the 3 experiments, phytohemagglutinin stimulation of peripheral blood lymphocytes was significantly decreased on day 3 or 4 after inoculation. Subsequently, on days 7 through 21, stimulations were similar between lymphocytes from inoculated birds and those from control birds. Pokeweed mitogen stimulation was affected minimally in virus-inoculated chickens. In each experiment, on day 7, the spontaneous [3H]thymidine uptake was greater in nonstimulated lymphocyte cultures from inoculated chickens than in such cultures from control chickens. In an additional experiment, chickens 1 week of age were exposed to a pathogenic vaccinal virus given in their water. The vaccinal virus exposure resulted in significant decrease of phytohemagglutinin stimulation of lymphocytes on days 3 and 7 of the experiment. A significant decrease in pokeweed mitogen stimulation was observed on day 10 after inoculation.     

The effects of water supplementation with vitamin E and sodium salicylate (Uni-Sol) on the resistance of turkeys to Escherichia coli respiratory infection

The objective of this study was to determine the prophylactic efficacy of two commercial products, soluble vitamin E and soluble sodium salicylate (Uni-Sol), in an Escherichia coli respiratory challenge. The drinking water of male turkey poults was nonsupplemented or supplemented with either vitamin E or Uni-Sol or a combination of both at dosages recommended by the manufacturer. There were 110 birds in each of the four treatments, housed in four floor pens per treatment. At 5 wk of age, birds in half of the pens were challenged with an air sac inoculation of approximately 50 colony-forming units of E. coli. Water treatment commenced 5 days before challenge and continued for 2 wk after challenge, when birds were necropsied. All water treatments prevented the decrease in body weight due to E. coli challenge; however, either vitamin E or Uni-Sol alone, but not the combination of the two, decreased body weight in nonchallenged controls. Either vitamin E or Uni-Sol treatment alone, but not the combination of the two, significantly decreased mortality and air sacculitis scores of challenged birds, and all treatments decreased the isolation rates of E. coli from the liver. All treatments protected liver, spleen, and bursa weights (relative to body weight) from the effects of E. coli challenge, and Uni-Sol alone or vitamin E with Uni-Sol protected relative heart weights from the effect of challenge. Uni-Sol treatment alone increased the main effect mean total leukocyte counts and the number and percent of lymphocytes. Uni-Sol in combination with vitamin E increased the number of lymphocytes of challenged birds. Uni-Sol alone decreased the main effect mean heterophil/lymphocyte ratio (H/L) ratio, whereas vitamin E alone increased the H/L ratio of challenged birds. These results indicate that treatment of turkey poults with vitamin E or Uni-Sol prior to and during the stressful events that can lead to colisepticema may decrease disease incidence and mortality.     

The Comparison of Antioxidative/Oxidative Profile in Colostrum,Milk and Blood of Early Post‐Partum Cows During their First and Second Lactation

The aim of the study was to compare antioxidative/oxidative profile in blood, colostrum and milk of early post‐partum cows during their first and second lactation. A total of 19 healthy, primiparous cows were included in experiment and samples were collected during 2 years from the same animals immediately after parturition, 24, 48 h as well as 6 and 12 days later. All parameters including the activity of glutathione peroxidase (GSH‐Px), total antioxidant capacity (TAC), the content of vitamin A, C as well as the contents of products of lipid and protein peroxidation were determined by the use of spectrophotometric methods. Comparing the profile within lactation, TAC and GSH‐Px activity in blood showed decreasing trends, while parameters of lipid and protein peroxidation fluctuated. All examined parameters in colostrum and milk except from intermediates of lipid peroxidation exhibited increasing trends. These results which showed dynamic changes of antioxidative/oxidative profile not only in blood but also in colostrum/milk within examined period of time suggested appropriate answer of organism to current challenge. Moreover, not uniform but detectable changes between first and second lactation suggested that two consecutive lactations are not the same. Comparing first and second lactation, TAC and parameters of lipid and protein peroxidation in blood showed increasing tendency in second as first lactation while GSH‐Px activity was opposite. The content of antioxidative vitamins and SH groups in colostrum/milk showed increasing tendency in second as first lactation, while TAC and content of end products of lipid peroxidation showed opposite trend, and GSH‐Px together with intermediates of lipid peroxidation remained stable. Molecular and biochemical background for it require further elucidation.     

药物对球虫感染鸡血液及生化指标的影响

1日龄艾维因肉鸡分为 4个组 ,即中药组、马杜霉素组、感染不给药组和不感染不给药组 ,每组 2 0只。中药组从 1日龄开始即投喂含 0 .1%中草药复方制剂 (由绞股蓝皂甙、去油鸦胆子仁等组成 )的饲料 ;马杜霉素组从 12日龄起投喂含马杜霉素 5 mg/ kg的饲料。前 3组于 14日龄感染鸡柔嫩艾美耳球虫孢子化卵囊。卵囊攻击前及攻击后 4、7d分别采血 ,测定血液红细胞数、血钾、血钠、血磷、血清白蛋白和血清总蛋白含量。结果表明 ,卵囊攻击后 4、7d,感染不给药组的红细胞数显著低于其他各组 (P<0 .0 5 ) ,卵囊攻击后 7d,血钾浓度显著高于其他各组 (P<0 .0 5 ) ,血清白蛋白和血清总蛋白显著低于其他各组 (P<0 .0 5 ) ;卵囊攻击后 7d,中药组血液红细胞数显著低于不感染不给药组 (P<0 .0 5 ) ,但显著高于感染不给药组 (P<0 .0 5 ) ;马杜霉素组的各项测定指标与不感染不给药组相比无显著差异 (P>0 .0 5 ) ;卵囊攻击后 ,各组间的血磷和血糖值无显著差异 (P>0 .0 5 )。结果提示 ,药物能抵抗球虫感染 ,血液各项指标得以保持相对恒定。     

Vitamin E concentration in the blood serum of sows during pregnancy and lactation]

The dynamics of vitamin E in the blood serum of sows of the Slovak Large White breed was studied from the 10th day of gravidity to the 20th day of lactation. A slight variation was observed in the average values of serum vitamin E from the 10th to the 50th day of gravidity (from 0.134 to 0.122 and 0.129 mg per 100 ml). A rise to the absolutely highest average values of serum concentration of vitamin E, 0.166 mg per 100 ml, was ascertained in the period from the 70th to the 90th day of gravidity. In the subsequent period, i.e. 110th day of gravidity, the value dropped to 0.120 mg per 100 ml, and on the 5th day of lactation the absolutely lowest value (0.095 mg per 100 ml) for the whole study was obtained. On the 20th day of lactation the serum concentration of vitamin E increased on an average to 0.103 mg per 100 ml. These data indicate the critical periods in the levels of vitamin E; these are from the 90th to the 100th day of gravidity and the first days of lactation when the concentration of vitamin E markedly decreases. If vitamin E is not supplemented to the sows during gravidity in sufficient amounts, preclinical and clinical vitamin E deficiency can be expected to occur.     

Dietary omega-3 fatty acid supplementation does not impair vitamin E status or promote lipid peroxidation in growing horses

Omega-3 (n-3; ω-3) fatty acids (FA) are often included in the diet for their potential health benefits. However, because oxidative potential is increased with the degree of unsaturation in vitro, polyunsaturated FA such as eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) may be at increased risk of lipid peroxidation. We aimed to determine the effects of dietary n-3 FA supplementation on antioxidant status and lipid peroxidation in yearling horses. Quarter Horses (mean ± SEM; 14.6 ± 0.2 mo) were randomly assigned to receive no n-3 FA supplementation (CON; n = 6) or 60 mg n-3/kg body weight from milled flaxseed (FLAX; n = 6) or encapsulated fish oil (FISH; n = 6). All horses received a basal diet of mixed grain concentrate fed individually at 1.5% body weight (dry matter basis) and ad libitum bahiagrass pasture forage. Blood samples were obtained before and after 70 d of supplementation to evaluate vitamin E, selenium, lipids, antioxidant status, and oxidative stress. Data were analyzed using a mixed model ANOVA with repeated measures. Supplementation with n-3 FA did not reduce serum vitamin E or Se and, in fact, elevated (P ≤ 0.0003) vitamin E status in FISH horses. At day 70, serum triglycerides were lower in FISH and FLAX horses than CON horses (P ≤ 0.02) and F2-isoprostanes were lower in FISH than CON horses (P = 0.0002). Dietary n-3 FA had no effect on cholesterol, reduced and oxidized glutathione, glutathione peroxidase, and thiobarbituric acid-reactive substances. In growing horses fed to meet their vitamin E requirements, supplementation with 60 mg n-3/kg body weight did not negatively affect vitamin E status or promote lipid peroxidation. Elevated vitamin E status in horses fed FISH, coupled with lower serum F2-isoprostanes, further suggest that the longer-chain, highly unsaturated n-3 FA, EPA and DHA, may actually attenuate lipid peroxidation.     

表达传染性喉气管炎病毒gB基因重组鸡痘病毒疫苗免疫持续期试验

将200003批疫苗免疫4周龄SPF鸡,免疫后的7、14、21、30、60、90、120、150、180和225 d分别采血,分离血清,采用ELISA方法检测血清抗FPV抗体,结果表明重组疫苗免疫后14 d,免疫鸡血清抗体已经全部阳转,免疫后的21 d血清抗FPV的抗体出现峰值,此后便开始下降,到免疫后的6个月抗体水平已经接近阴性对照的水平.用ILTV WG株和FPV 102株强毒进行的攻毒保护试验与血清检测的结果基本一致,在免疫后的5个月内可以使免疫鸡获得100%(10/10)保护,免疫后的6个月对ILT和FP的免疫保护分别为1/7和2/10,此时需要对鸡群实施二次免疫.其他5批疫苗(200001、200002、200101、200102和200103)免疫SPF鸡后5个月用ILTV WG株和FPV 102株攻击也获得了完全保护.     

Relationship between vitamin E content and susceptibility to lipid peroxidation in tissues of the newly hatched chick.

1. The effect of supplementing the diet of the parent hen with vitamin E on the vitamin E content of the yolk and of embryonic and neonatal tissues was evaluated and the effects of elevated tissue concentrations of vitamin E on peroxidation susceptibility was examined. 2. Laying hens (Ross 1 broiler-breeder strain) were maintained on diets containing either 147 (control diet) or 365 (high vitamin E diet) microg vitamin E/g feed. 3. In the day-16 embryo, the concentrations of of vitamin E in the yolk sac membrane, liver, brain and lung were respectively 5.0, 4.3, 1.7 and 5.6 times greater for those derived from the hens on the high vitamin E diet compared with those from the control group. 4. In the day-old chick, the concentrations of vitamin E in the yolk sac membrane, liver, brain and lung were respectively 14.8, 2.8, 3.0 and 5.1 times greater for those derived from hens on the high vitamin E diet compared with those from the control group. 5. Homogenates of tissues from the day-old chick were incubated in the absence and presence of Fe2+ in order to determine the extent of spontaneous and iron-stimulated peroxidation as measured by the generation of thiobarbituric acid reacting substances. For the chicks derived from hens on the control diet, the brain was markedly more susceptible to both spontaneous and iron-stimulated peroxidation than were the other tissues. Tissues from the chicks derived from the hens on the high vitamin E diet exhibited significantly reduced susceptibilities to peroxidation. In particular, the susceptibility of the brain was reduced to the same level as that of the other tissues. 6. It is concluded that the high peroxidative susceptibility of the chick's brain can be normalised by supplementation of the parent hen with vitamin E.     

Absorption of Different Oral Formulations of Natural Vitamin E in Horses

The objective of this study was to determine the effect of vitamin E source on plasma vitamin E concentration. Five different formulations of natural source vitamin E (4,000 IU/day) were supplemented to Standardbred mares (n = 4 per group) for 14 days. Treatment 1 was given 10 g of 400 IU/g natural acetate (RRR-α-tocopheryl-acetate) powder, treatment 2 was given 6.66 g of 600 IU/g natural acetate powder, treatment 3 was given 6.66 g of 600 IU/g natural alcohol (RRR-α-tocopherol) powder, treatment 4 was given 20 g of 200 IU/g micellized natural alcohol powder, and treatment 5 was given 8 mL of 500 IU/mL micellized natural alcohol liquid. Blood samples were collected before supplementation (day 0), after day 7 and day 14 of supplementation, and analyzed for plasma α-tocopherol. Treatments 1, 2, and 3 increased (P < .05) from days 0 to 7, but remained similar at day 14. Treatments 4 and 5 also increased (P = .004, and P < .0001, respectively) from days 0 to 7 and were higher (P < .05) than treatment 1, 2, and 3. Plasma levels peaked at day 7 and either plateaued or decreased (treatment 5, P = .004) at day 14. The micellized alcohol formulations remained elevated (treatment 4) or decreased (treatment 5) after achieving peak blood concentration and, as hypothesized, tended to have plasma concentrations higher than the other vitamin E forms. Care should be taken to ensure that the most active biologically available form of vitamin E is provided in the diet to maximize its efficiency.     

Antioxidant supplementation and subsequent oxidative stress of horses during an 80-km endurance race

This study tested the development of oxidative stress and the effects of antioxidant supplementation in an 80-km ride. A precompetition survey revealed that no competitor would participate without vitamin E supplementation; therefore, 46 horses were paired for past performances and randomly assigned to two groups of 23 each for 3 wk of supplementation before the ride. One group (E) was orally supplemented with 5,000 IU of vitamin E per day; the other group (E+C) received that dose of vitamin E plus 7 g/d of vitamin C. Blood samples, temperature, and heart rate were taken the day before the race, at 21 and 56 km during the ride, at completion, and after 20 min of recovery. Plasma was assayed for lipid hydroperoxides, alpha-tocopherol, total ascorbate, albumin, creatine kinase (CK), and aspartate aminotransferase (AST). Total glutathione and glutathione peroxidase activity were determined in red blood cells and white blood cells. Thirty-four horses completed the race, 12 horses (six in E and six in E+C) did not finish for reasons including lameness, metabolic problems, and rider option. Plasma ascorbate was higher (P = 0.045) in the E+C group than in the E group. Other than ascorbate, neither antioxidant status nor CK and AST activities were affected by supplementation with E+C vs. E. Red blood cell glutathione peroxidase, white blood cell total glutathione, lipid hydroperoxides, CK, and AST increased, and red blood cell total glutathione and white blood cell glutathione peroxidase activity decreased with distance (P < 0.001). Positive correlations were found for plasma lipid hydroperoxides on CK (r = 0.25; P = 0.001) and AST (r = 0.33; P < 0.001). These results establish an association between muscle leakage and a cumulative index of oxidative stress.     

对虾白斑综合征病毒单抗介导间接ELISA的建立

从白斑综合征病毒（WSSV）青岛株感染的克氏原螯虾（Canbarus proclarkii）中提纯病毒，用纯化病毒免疫BALB／c小鼠，采用细胞融合法获得4株阳性杂交瘤细胞，分别命名为1B1、1E4、4E6和4E5。4株单抗均为IgM。4E5株单抗在免疫转印中与37500左右的病毒蛋白条带呈阳性反应。用此株单抗作一抗，建立检测病毒蛋白的间接ELISA。该方法用于人工感染WSSV的螯虾组织样品中病毒的检测，48h后即有阳性检出，而正常螯虾组织均呈阴性。     

Susceptibility of laboratory animals to experimental infection with Ife virus

The susceptibility of rabbits, domestic chickens and albino rats to experimental infection with Ife virus was investigated. Neither pyrexia nor clinical signs of disease were observed in infected rabbits or chickens. Low-grade viraemia (10(1.0) mouse lethal doses per 0.02 ml) occurred in intracerebrally (i.c.) inoculated chicks on the second day post-infection. Complement-fixing antibody was detected on the 14th day post-inoculation in rabbits and on the 7th day in chickens. Infant rats less than 3 and 5 days of age died after subcutaneous (s.c.) and i.c. inoculation, respectively; older rats survived infection. Ife virus titres were highest in the brain following both i.c. and s.c. inoculation.     

硒和维生素E在硒缺乏动物自由基代谢中作用机制的研究

为阐明硒缺乏动物自由基代谢与硒缺乏症发病学的关系，以及硒和ＶＥ在自由基代谢中的作用采用低Ｓｅ日粮饲喂小鼠，并对血液、肝组织丙二醛、硒谷胱甘肽过氧化物酶、相关向量元素及自由基水平进行了系统检测。