硒对奶牛红细胞谷胱甘肽过氧化物酶活力的浓度依赖性研究

实验通过在缺硒地区奶牛血清中添加一定量外加硒（Na2SeO3）测其谷胱甘肽过氧化物酶活力。结果表明，一定浓度内，硒含量与谷胱甘肽过氧化物酶活力呈正相关，一定量外加硒可以提高血清中GSH－Px活力。从0.01μg/L开始，GSH－Px活力随硒浓度的增加而增加，当外加硒浓度达到0.1μg/L时，GSH－Px活力达到最大值，眩后进一步增加硒浓度，GSH－Px活力非但不增加，呈明显下降趋势。     

非依赖硒型谷胱甘肽过氧化物酶的测定

谷胱甘肽过氧化物酶是机体的重要抗氧化酶,按其组成可分为依硒型谷胱甘肽过氧化物酶(Se—GSH—Px)和非依赖硒型谷胱甘肽过氧化物酶(Non Se—GSHPx)之分。两型酶催化作用的一个重要区别在于对过氧化物有特殊的选择性。以过氧化氢(H_2O_2)为底物时可催化     

牦牛胎盘对小鼠组织中谷胱甘肽过氧化物酶活性的影响

为探讨牦牛胎盘对小鼠组织中谷胱甘肽过氧化物酶（GSH—Ix）活性的影响。根据采集到胎盘的海拔高度将100只小白鼠随机分为高海拔组、中海拔组、低海拔组和对照组，连续28d分别灌服不同海拔的牦牛胎盘和生理盐水，然后处死小鼠快速采取肝、肺、心肌、骨骼肌、脾脏和肾幢，测定各组织内GSH—Px的活性。结果表明，各海拔组肝脏、高中海拔组肺脏和高海拔组骨骼肌中GSH—Px活性极显著的高于对照组，差异极显著（P〈0．01）；低海拔组肺脏、中低海拔组骨骼肌和高中海拔组肾脏中GSH—Px活性显著的高于对照组，差异显著（P〈0．05）。说明牦牛胎盘能提高小鼠肝、肺、骨骼肌和肾脏中GSH—Px的活性。     

氟中毒家蚕幼虫血淋巴中谷胱甘肽过氧化物酶的活性

为了解家蚕氟中毒的机理 ,研究了氟中毒家蚕幼虫血淋巴中谷胱甘肽过氧化物酶 (GSH—Px)的活性。正常的家蚕 5龄幼虫血淋巴中GSH—Px活性在龄中期较强 ,龄初和龄末较弱。幼虫添食 10mmol/L的氟化钠溶液后 ,GSH—Px的活性显著增强     

关于畜禽谷胱甘肽过氧化物酶(GSH—Px)的研究近况

谷胱甘肽过氧化物酶是含硒酶。国外近年对畜禽的全血、血清、血浆及器官组织中GSH—Px的活力与硒的关系进行了比较广泛的研究。各国的研究者认为GSH—Px活力与硒有相当大的相关性,而且GSH—Px活力的变化可作为评价机体中硒的营养状况和绘制不同区域的地理地质带略图的依据。为此,将该酶的研究概况按畜禽种类分述如下:     

日粮硒对雏鸡肝脏、胰腺谷胱甘肽过氧化物酶活力影响的试验

谷胱甘肽过氧化物酶可分为依硒型(Se—GsH—Px)和非依硒型(NonSe—GSH—Px)。Tappel证实,非依硒型谷胱甘肽过氧化物酶就是谷胱甘肽硫转移酶,并指出在评定硒营养时,仅测定依硒型谷胱甘肽过氧化物酶是不充分的,测定非依硒型谷胱甘肽过氧化物酶的活力,有助于揭示动物种属不同对硒反应性疾病发生与否的物质基础,也有助于进一步阐明硒缺乏症的发病机理。为此,本试验采用异丙基过氧化氢法,探讨日粮硒对雏鸡肝脏、胰腺含硒量及依硒型和非依硒型谷胱甘肽过氧化物酶活力的影响。     

多种微量元素缺乏症防治制剂对肉仔鸡血液谷胱甘肽过氧化物酶活力的影响

用自制的多种微量元素防治制剂的2种剂型(多微控释制剂和多微散剂)对肉仔鸡进行微量元素缺乏症防治试验，分别于试验第15、30和45d采集静脉血液进行谷胱甘肽过氧化物酶(GSH—Px)活力分析。结果表明，2种制剂均可以显著提高(P＜0．05)内仔鸡血液中GSH—Px活力，增强内仔鸡的抗氧化能力；多微定量控释制剂的效果优于散剂。     

酵母硒在鲫鱼饲料中的应用

硒作为动物体必需的微量元素，是谷胱甘肽过氧化物酶（GSH—Px）的辅助因子，此酶能减少动物体内过氧化氢、脂肪酰氢过氧化物和脂肪酰乙醇的含量，从而减少脂肪的氧化。硒对动物的生长发育、免疫机能和抗氧化等方面发挥着重要作用。     

硒对黄粉虫谷胱甘肽过氧化物酶活性的影响

为探讨亚硒酸钠对黄粉虫幼虫血淋巴谷胱甘肽过氧化物酶（GSH—PX）活性的影响,将黄粉虫的中龄幼虫随机分成6组,饲喂含不同浓度的亚硒酸钠饲料。采用DTNB比色法测定GSH—PX活性。结果显示,饲喂含亚硒酸钠的饲料后黄粉虫幼虫血淋巴GSH—PX活力都明显上升：饲喂同一浓度的亚硒酸钠,幼虫血淋巴GSH—PX活力均比对照组高,只有加硒浓度为20mg／kg．80mg／kg在第16d时,黄粉虫血淋巴GSH—PX活力随着饲喂时间的延长而显著上升;饲喂不同浓度的亚硒酸钠,在硒浓度为5mg／kg、10mg／kg时,黄粉虫血淋巴GSH-PX活力随亚硒酸钠浓度的增加显著上升,在硒浓度为20mg／kg时开始下降。     

一例哺乳猪缺硒症的诊治

硒是谷胱甘肽过氧化物酶（GSH—Px）和磷脂过氧化氢谷胱甘肽过氧化物酶（PLGSH—Px）的活性成分．是动物生长发育不可缺少的微量元素之一。硒在体内主要是抗氧化作用．通过GSH—Px和PLGSH—PX催化机体代谢过程中产生的过氧化物转化为无毒产物，动物缺硒时．机体代谢过程中产生的过氧化物不能及时清除，可引起细胞变性、坏死，功能降低或丧失．表现出一系列临床症状及病理变化。     

Effect of subcutaneous selenium injection and supplementary selenium source on blood selenium and glutathione peroxidase in feedlot heifers

This study measured the effect on glutathione peroxidase (GSH-Px) and selenium (Se) in whole blood and plasma associated with subcutaneous Se injections in beef heifers fed organic or inorganic Se. Heifers (n = 120) were randomly divided into 2 groups, 1 of which received subcutaneous Se injections. Both groups were given the same total mixed ration with 3 mg of organic or inorganic Se daily. Until week 2, heifers that had received Se injections showed higher concentrations of plasma Se and GSH-Px and whole blood Se (P < 0.001) than those having had no injections. Concentrations of plasma Se and GSH-Px were higher in the group receiving organic Se than the group receiving inorganic Se. Whole blood GSH-Px concentrations increased significantly (P < 0.001) throughout a 12-week period but were not affected by Se source. Combination of Se injections and supplementation could help maintain normal Se and GSH-Px blood status in beef heifers during the first few weeks in the feedlot.     

Comparative effect of selenium in wheat, barley, fish meal and sodium selenite for prevention of exudative diathesis in chicks

Groups af White Leghorn chicks obtained from dams deprived on selenium (Se), were fed from hatching a low-Se-vitamin E basal diet alone, or supplemented with 0.02, 0.04, 0.06 or 0.08 mg Se/kg diet, as sodium selenite (Na2SeO₃ · 5H₂O), wheat, barley or fish meal. Prevention of the Se-vitamin E deficiency responsive disease exudative diathesis (ED) as it was clinical observed, induction of the plasma Se dependent enzyme glutathione peroxidase (GSH-Px) activity, and Se concentration in the cardiac muscle were observed to be dietary Se level and source dependent. Slope ratio assay was applied to estimate the biological availability of Se in the natural sources relative to Se in sodium selenite. For the prevention of ED, the bioavailability of Se in wheat, barley and fish meal was 99, 85 and 80 %, respectively. The increase in the plasma GSH-Px activity revealed a bioavailability for Se in wheat, barley and fish meal of 79, 71 and 66 %, respectively. Using retention of Se in the cardiac muscle as the bioassay, a bioavailability of 108, 87 and 100 % was calculated for wheat, barley and fish meal Se, respectively.     

Biochemical and physiological indicators of selenium status in animals

Selenium (Se) concentrations in animal tissues vary with the tissue and with the amount and chemical form of Se in the diet. In cattle, sheep and swine, Se concentrations rank in kidney greater than liver greater than heart greater than skeletal muscle greater than adipose tissue. Selenium concentrations (wet basis) in skeletal muscle of swine (.03 to .52 ppm) reflect natural dietary Se concentrations ranging from .03 to .49 ppm. Inorganic Se additions to diets low in natural Se (.05 ppm) increase skeletal muscle Se concentrations until dietary Se levels are adequate. After a period of Se repletion, skeletal muscle Se concentrations should be at least .08 ppm on a wet basis. Selenium concentrations in plasma, serum or whole blood are also related to inorganic Se intake and rise in direct relation to each other in the deficient to adequate range. Plasma or serum Se concentrations of .08 to .12 ppm are consistent with dietary adequacy. Selenium-dependent glutathione peroxidase (GSH-Px) activity of plasma or whole blood may also be used to assess Se status in some animals since plasma or whole blood Se concentrations are positively correlated with GSH-Px activity in animals that are low to adequate in dietary inorganic Se. However, inter-laboratory variation in GSH-Px values is large, and it is doubtful that limits of normalcy developed in one laboratory are applicable in others. In certain tissues it is important to distinguish between GSH-Px and glutathione (GSH) S-transferases, which can reduce organic hydroperoxides but which are not Se-dependent. It is also important that the instability of GSH-Px be considered so that losses in activity during handling and storage may be minimized. Urinary Se excretion and Se retention as percentages of Se intake may be helpful in assessing Se status when facilities for metabolism studies are available.     

A comparison of selenomethionine and sodium selenite as a supplement in chicken feeds

Fifty Norwegian-bred White Leghorn chickens, 20 weeks of age, were divided into 3 groups and fed a basal diet containing 0.09 mg Se/kg dry matter (D.M.). One group was given a supplement of 0.5 mg Se/kg as seleno-DL-methionine (Se-Met), another group 0.5 mg/kg as sodium selenite while one group served as control. After 10 weeks, all 3 groups were offered the basal diet without added selenium (Se) for a further 9 weeks. At the end of the supplementation period, significantly higher Se levels in blood and tissues were observed in the Se-Met group. These higher levels were not reflected in the glutathione peroxidase (GSH-Px) activity. During the first weeks of the depletion period, there was a steady decrease in Se levels and GSH-Px activity in blood and tissues in both the Se supplemented groups. However, Se levels in the group receiving sodium selenite fell almost to- those in the control group after 2 weeks, while the levels in the Se-Met group did not approach the control levels, even after 9 weeks. There were no differences as regards tissue GSH-Px activity between the 2 supplemented groups, which in both groups nearly reached the control level after 2 weeks. There was, however, a more rapid decrease in GSH-Px activity in whole blood in the sodium selenite group from week 0 to 5 as compared to the Se-Met group. The results obtained in this study support the theory that different forms of Se occupy separate metabolic pools in the body, and that the Se pool resulting from Se-Met supplementation can be mobilized for GSH-Px synthesis in a depletion period.     

Effect of organic and inorganic selenium sources and levels on sow colostrum and milk selenium content

A study was conducted to evaluate the short-term effects of feeding two dietary Se sources at various Se levels on the transfer of Se to the dam's milk and nursing pig. Six dietary treatments were arranged in a 2 x 2 factorial arrangement with two additional treatments in a randomized complete block designed experiment. Inorganic (sodium selenite) or organic (Se-enriched yeast) Se sources were added to the diet at .15 or .30 ppm Se. A non-Se-fortified corn-soybean meal basal diet served as a negative control, and a sixth group was fed .15 ppm Se from both inorganic and organic Se sources. A total of 43 sows were fed their treatment diets at 2.2 kg/d from 6 d prepartum to parturition and at full feed through a 14-d lactation period. Ten sows were initially bled at 6 d prepartum, and three sows and three pigs from their litters were bled at 7 and 14 d postpartum. Serum was analyzed for its Se concentration and glutathione peroxidase (GSH-Px) activity. Colostrum was collected within 12 h postpartum and milk at 7 and 14 d of lactation. When the basal diet was fed, sow serum GSH-Px activity declined from 6 d prepartum and remained low throughout lactation. When dietary Se levels increased, sow serum Se concentration and serum GSH-Px activity increased (P < .05) at both 7 and 14 d postpartum. The short-term feeding of either Se source at .15 or .30 ppm Se did not affect colostrum Se content when inorganic Se was fed, but it was increased when organic Se was provided. This resulted in a significant Se source x Se level interaction (P < .01). Milk Se at 7 and 14 d postpartum was 2.5 to 3 times higher when the organic Se source was provided and resulted in a significant Se source x Se level interaction (P < .05). When the combination of inorganic and organic Se was fed at .15 ppm Se, colostrum and milk Se contents were similar to those of sows fed .15 ppm Se from the organic Se source. Pig serum GSH-Px activity was not affected at 7 and 14 d of age by dietary Se level or Se source fed to the sow, but serum Se increased (P < .05) as dietary Se level increased, particularly when sows had been fed organic Se. The results demonstrated that organic Se increased milk Se content more than did inorganic Se and increased the nursing pig's serum Se. These results indicate that inorganic Se was more biologically available for sow serum GSH-Px activity, but organic Se was more effectively incorporated into milk.     

Effects of pre- or postpartum selenium supplementation on selenium status in beef cows and their calves

The effect of Se supplementation before or after calving on Se status in deficient cows and their calves was studied using 72 beef cows in two experiments. In Exp. 1, cows calving in February or March 1997 were supplemented orally for 15 d in late pregnancy with 13.0, 32.5, or 45.5 mg of Se/d as sodium selenite. Glutathione peroxidase (GSH-Px) activities were measured in red blood cells (RBC) or plasma of cows and calves at d 15 and between d 17 and 88 after calving. In Exp. 2, cows calving in January 1997 were supplemented orally with .0, 13.0, or 32.5 mg of Se/d for 15 d postpartum, and calves were injected with 1.38 mg of Se when 2 d old and at an average age of 49 d. The GSH-Px activities were measured in 30-d-old calves and in cows and calves between d 77 and 115 after calving. In both experiments, Se supplementation resulted in adequate Se status for the dams. The increase in RBC GSH-Px activity was faster with 45.5 mg of Se/d, and GSH-Px activities remained high for up to 98 d after the end of supplementation. The improvement in Se status in calves as a result of maternal supplementation was greater in Exp. 1 than in Exp. 2, suggesting that the placental transfer of Se is more efficient than milk transfer. Prepartum oral Se supplementation of deficient beef cows with 13.0 mg of Se/d for 15 d allowed adequate Se status of dams and calves, and 45.5 mg of Se/d resulted in a faster improvement of Se status. Parenteral administration of 1.38 mg of Se to newborn calves did not sustain normal Se status in calves issued from deficient cows.     

Selenium Status and GSH-Px Activity in Semen and Blood of Boars at Different Ages Used for Artificial Insemination

This study was performed to determine the relationship between selenium (Se) content and Se-dependent glutathione peroxidase (GSH-Px) activity in blood and semen, and semen quality of boars at different age used in an artificial insemination (AI) station. Routine macroscopic and microscopic analyses of semen quality were accompanied by measurement of Se content and GSH-Px activity in blood and semen. The Se concentration in blood plasma, seminal fluid and spermatozoa was measured by fluorometric method, the GSH-Px activity by a method based on NADPH-coupled reaction. A total of 155 ejaculates and 58 blood samples were investigated. The results of this study showed that there was no direct relationship between the Se content and GSH-Px activity in blood plasma and semen, and semen quality of sexual matured boars. The mechanisms controlling Se content and GSH-Px activity in blood and semen seem to be independent. The age of boars as a differentiating factor for Se content and GSH-Px activity in blood and semen is possible. It is concluded that a determination of Se status and/or GSH-Px activity in organism before Se supplementation is indicated.     

Beneficial Effect of N-acetylcysteine against Oxidative Damage in Mice Liver Induced by Streptococcus agalactiae Serotype Ⅰa Isolated from Cow

The assay was aimed to investigate the effect of Streptococcus agalactiae on oxidative damage in mice liver and the beneficial effect of N-acetylcysteine against the damage. Forty adult mice were divided into 4 groups (control, NAC, S.agalactiae and NAC+S.agalactiae) randomly. Colorimetry was used to detect the content of MDA and the activities of GSH-Px, GST and POD. The results showed that, compared with the control group, there were extremly significant reductions in the activity levels of GSH-Px, GST and POD (P<0.01) accompanied by a extremly significant increase in the MDA content (P<0.01) in bacteria infected group; extremly significant increases in the activity levels of GSH-Px, GST and POD (P<0.01) accompanied by a extremly significant reduction in the MDA content (P<0.01) in NAC group.Compared with S.agalactiae group, extremly significant increases in the activities of GSH-Px, GST and POD (P<0.01), and extremly significant reduction of the MDA content (P<0.01) could be observed in NAC+S.agalactiae group, but when it came to control group, extremly significant reduction in the activities of GSH-Px, GST and POD (P<0.01), and extremly significant increase of the MDA content (P<0.01) could be observed. Thus, the results suggested that infection of Ⅰa S.agalactiae isolated from bovine could induce oxidative damage in mice liver, and NAC (100 mg/(kg·BW)) pretreatment could enhance the activities of GSH-Px, GST and POD, and decrease the MDA content to reduce the damage degree.     

Effects of riboflavin supplementation and selenium source on selenium metabolism in the young pig

The effect of dietary riboflavin (B2) supplementation and selenium (Se) source on the performance and Se metabolism of weanling pigs was studied. Pigs fed a B2-supplemented (10 mg/kg) casein-glucose diet for 18 d gained faster than pigs fed the B2-unsupplemented diet. Percentage active erythrocyte glutathione reductase (GR) declined rapidly when pigs were placed on the B2-unsupplemented diet and was lower (P less than .01) than that of B2-supplemented pigs after 12 d on test. Percentage active erythrocyte GR values fell below 50% before other B2 deficiency signs became evident. Supplementation of diets with 10 mg B2/kg resulted in increased kidney and muscle glutathione peroxidase (GSH-Px) activity. The Se concentration of liver and heart increased and plasma Se levels decreased with dietary B2 supplementation. Riboflavin supplementation and Se source did not alter apparent Se absorption, but B2 supplementation decreased urinary Se and thus increased Se retention. Also, there was less urinary Se excretion when selenomethionine was the dietary Se source and consequently more Se was retained than when sodium selenite was the dietary Se source. In a final trial, B2 supplementation increased kidney, muscle, heart and brain GSH-Px activity when sodium selenite was the dietary Se source, but not when selenomethionine was the dietary Se source.     

辣木叶多糖对过氧化氢诱导奶牛乳腺上皮细胞氧化损伤的保护作用

奶牛乳腺上皮细胞(BMECs)在奶牛泌乳期代谢旺盛,导致活性氧(ROS)大量产生,从而诱发氧化应激.辣木叶多糖(MLP)能有效清除ROS和自由基,但其是否具有缓解BMECs氧化损伤的潜力尚不清楚.因此,本文以MLP为添加剂,探究其对过氧化氢(H2O2)诱导BMECs氧化损伤的保护作用.本试验首先将分离的BMECs置于含...