Stable gastric pentadecapeptide BPC 157 in honeybee (Apis mellifera) therapy,to control Nosema ceranae invasions in apiary conditions

Nosema ceranae can cause major problems, such as immune suppression, gut epithelial cell degeneration, reduced honeybee lifespan, or suddenly colony collapse. As a novel approach in therapy, we hypothesize the stable gastric pentadecapeptide BPC 157 in honeybee therapy, to control N. ceranae invasions in apiary conditions: BPC 157 treated sugar syrup (0.25 L sugar syrup supplemented with 0.1 μg/ml BPC 157), as well as the pure sugar syrup (0.25 L sugar syrup; control), was administered to honeybee colonies in feeders situated under the roof of the hives, during 21 consecutive days, at the end of beekeeping season. The strength of honeybee colonies was increased 20 and 30 days after initial feeding with BPC 157 supplement (Day 1, 36.100 ± 698; Day 20, 64.860 ± 468; Day 30, 53.214 ± 312 estimated number of honeybees), in field conditions. The similar successful outcome occurs with the N. ceranae spore loads counted in the homogenates of sampled adult honeybees (Day 1, 6.286 ± 2.336; Day 20, 3.753 ± 1.835; Day 30, 2.005 ± 1.534 million spores/bee). Accordingly, with the noted increased strength of the colonies fed with sugar syrup supplemented with BPC 157, the number of N. ceranae spores per honeybee gradually decreased as well. Besides, honeybees infected with N. ceranae fed with sugar syrup exhibited severe damage of midgut wall layers and epithelial cells. By contrast, in honeybees infected with N. ceranae fed with sugar syrup supplemented with BPC 157, all damages were markedly attenuated, damages of the outer muscular coat, in particular. In conclusion, the results of the first field trial on diseased honeybee colonies with BPC 157 indicate significant therapeutic effects with the used oral therapy with BPC 157 supplementation.     

Effectiveness of tilmicosin against Paenibacillus larvae, the causal agent of American Foulbrood disease of honeybees

American Foulbrood (AFB) of honeybees (Apis mellifera L.), caused by the Gram-positive bacterium Paenibacillus larvae is one of the most serious diseases affecting the larval and pupal stages of honeybees (A. mellifera L.). The aim of the present work was to asses the response of 23 strains of P. larvae from diverse geographical origins to tilmicosin, a macrolide antibiotic developed for exclusive use in veterinary medicine, by means of the minimal inhibitory concentration (MIC) and the agar diffusion test (ADT). All the strains tested were highly susceptible to tilmicosin with MIC values ranging between 0.0625 and 0.5 microg ml(-1), and with MIC(50) and MIC(90) values of 0.250 microg ml(-1). The ADT tests results for 23 P. larvae strains tested showed that all were susceptible to tilmicosin with inhibition zones around 15 microg tilmicosin disks ranging between 21 and 50mm in diameter. Oral acute toxicity of tilmicosin was evaluated and the LD(50) values obtained demonstrated that it was virtually non-toxic for adult bees and also resulted non-toxic for larvae when compared with the normal brood mortality. Dosage of 1000 mg a.i. of tilmicosin applied in a 55 g candy resulted in a total suppression of AFB clinical signs in honeybee colonies 60 days after initial treatment. To our knowledge, this is the first report of the effectiveness of tilmicosin against P. larvae both in vitro and in vivo.     

不同越冬饲料对蜜蜂中肠消化酶活性、组织发育状态以及抗氧化酶基因表达的影响

本试验旨在研究不同越冬饲料对蜜蜂中肠消化酶活性、组织发育状态以及抗氧化酶基因表达的影响,以便为广大蜂农选择越冬饲料提供参考。在2015年10月底选取群势相当的本地意大利蜜蜂(Apis mellifera L.)越冬蜂群(群内无储备越冬饲料脾)9群(5框蜂/群),随机分为3个试验组(3群/组),从11月2号开始分别以蜂蜜(蜂蜜组)、果葡糖浆(果葡糖浆组)和白砂糖水(白砂糖∶水=2∶1,蔗糖组)为越冬饲料进行饲喂,饲喂至11月下旬蜂群进入越冬期。整个试验期为2015年10月底至2016年3月初。分别于越冬前(11月初)、越冬中期(1月初)和越冬后(3月初)采集蜜蜂中肠,测定中肠消化酶(淀粉酶、蔗糖酶和蛋白酶)活性,在越冬中期采集蜜蜂中肠用于中肠组织发育状态和抗氧化酶基因[超氧化物歧化酶1(Sod1)、超氧化物歧化酶2(Sod2)和过氧化氢酶(CAT)]相对表达量等指标的检测。结果表明:在越冬中期,果葡糖浆组和蜂蜜组的蜜蜂中肠内淀粉酶活性显著高于蔗糖组(P0.05)。在越冬中期和越冬后,饲喂不同越冬饲料的蜜蜂中肠内蔗糖酶活性差异不显著(P0.05)。在越冬中期,果葡糖浆组的蜜蜂中肠内蛋白酶活性显著高于蔗糖组和蜂蜜组(P0.05)。蜂蜜组和蔗糖组的蜜蜂中肠肠壁厚度极显著大于果葡糖浆组(P0.01),且蜂蜜组和蔗糖组的蜜蜂中肠隐窝深度也极显著大于果葡糖浆组(P0.01)。在越冬中期,蔗糖组的蜜蜂中肠Sod1基因的相对表达量显著高于蜂蜜组和果葡糖浆组(P0.05)。由此得出,蜂蜜能够提高越冬蜂中肠消化酶活性,蜂蜜和白砂糖有利于越冬蜂中肠组织的发育,而且白砂糖能够提高越冬蜂中肠抗氧化酶基因的表达。因此,蜂蜜和白砂糖比果葡糖浆更适合作为蜜蜂的越冬饲料。     

In vitro and in vivo susceptibility of the honeybee bacterial pathogen Paenibacillus larvae subsp. larvae to the antibiotic tylosin

The minimal inhibitory concentrations (MICs) of tylosin were determined to 67 strains of Paenibacillus larvae subsp. larvae, the causal agent of American Foulbrood (AFB) disease, from different geographical origins. MIC values obtained ranged from 0.0078 to 0.5 microg/ml. These very low values imply that no resistance to tylosin was found in any isolate of the Foulbrood pathogen. The measurement of diseased larvae with AFB-clinical symptoms in three different field studies demonstrated that tylosin treatment could be effective in vivo. No negative effects in colonies were noted at any dosage rates or forms of application. These studies demonstrate that tylosin, as tartrate, can be used to treat AFB in honeybee colonies.     

Efficacy of silver ions against Sacbrood virus infection in the Eastern honey bee Apis cerana

Although silver is known to be a broad-spectrum biocidal agent, the effects of this metal against Sacbrood virus have not yet been investigated. In this study, we evaluated the efficacy of silver ions against natural Korean sacbrood virus (KSBV) infection of Apis (A.) cerana. Ten KSBV-infected colonies containing A. cerana with similar strength and activity were selected from an apiary located in Bosung-gun (Korea). Among these, five colonies were randomly assigned to the treatment group that was fed sugar syrup containing 0.2 mg/L silver ions. The other colonies were assigned to the untreated control group in which bees were given syrup without the silver ions. To assess the efficacy of the silver ions, colony strength, colony activity, and the number of dead larvae per hive were measured. During the experimental period, the test group maintained its strength and activity until day 32 while those of bees in the control group decreased sharply after day 8 to 16. Survival duration of the test group was significantly longer (40 days) than that of the control group (21 days). These results strongly indicated that silver ions are effective against KSBV infection in A. cerana.     

Phenotypic and genotypic characterization of Paenibacillus larvae isolates

Paenibacillus larvae is the causative agent of American Foulbrood (AFB), a severe disease of honeybees (Apis melifera). The aim of this work was to develop a strategy for the subtyping and the epidemiological analysis of P. larvae. Phenotypic characterisation, susceptibility to several antibiotics, electrophoresis of whole bacterial proteins, rep-PCR, ribotyping and DGGE were assessed using a collection of P. larvae isolates from different Uruguayan and Argentinean locations. Results indicated that there are two P. larvae genotypes circulating in Uruguay ERIC I-BOX A (worldwide distributed) and ERIC I-BOX C (exclusively detected in Argentina until this study). These results suggest that P. larvae isolates had moved between Argentina and Uruguay, probably through the Uruguay River. Patterns of whole bacterial proteins, DGGE and ribotyping did not improve the P. larvae intraspecific discrimination. Antibiotic susceptibility assays showed that 100% isolates were OTC-sensitive and 22% (belonging to ERIC I-BOX A group) were sulfisoxazole-resistant. This work may contribute to the elucidation of basic aspects related to the epidemiology of AFB in Uruguay and in the region.     

Influence of dietary protein, fat or amino acids on the response of weanling swine to aflatoxin B1

Two experiments were conducted using corn from clean or aflatoxin B1 (AFB1)-contaminated (182 ppb) sources. Weanling pigs (28 d) were fed one of eight dietary treatments arranged in a 2 x 2 x 2 factorial design. In Exp. 1 (192 pigs), treatments varied in corn source (clean or AFB1-contaminated), CP level (18 or 20%) and added fat (0 or 5%). At the end of the 28-d growth trials, plasma samples were obtained. An AFB1 x CP level interaction was detected (P less than .05) for growth rate (ADG), feed intake (FI) and feed/gain ratio (F/G). Feeding AFB1 reduced (P less than .05) ADG (.30 vs .37 kg/d) and FI (.57 vs .66 kg/d) and increased F/G (1.88 vs 1.78) of pigs fed 18% CP diets. Performance of pigs fed 20% CP diets was not altered by AFB1. Adding 5% fat to diets improved (P less than .05) F/G but did not improve ADG of pigs fed AFB1. There was an AFB1 x CP x fat interaction (P less than .05) for plasma cholesterol. Adding fat or increasing the CP level prevented the depression of plasma cholesterol in pigs fed AFB1. In Exp. 2 (96 pigs), all diets contained 18% CP and the treatments varied in corn source (clean or AFB1-contaminated), added L-lysine HCl (0 or .25%) and added DL-methionine (0 or .15%). Feeding AFB1 reduced (P less than .05) ADG of pigs fed the 18% CP diet (.44 vs .50 kg/d) but not of pigs fed diets supplemented with .25% lysine.(ABSTRACT TRUNCATED AT 250 WORDS)     

基础日粮添加蜂胶对母猪生产性能的影响

为了研究蜂胶对母猪生产性能的影响,选择16头配种时间、胎次基本一致的长大妊娠母猪为材料,随机分成对照组和试验组。对照组只饲喂基础日粮,试验组则在基础日粮中添加蜂胶。试验从母猪妊娠81d进产房开始,到仔猪21日龄断奶后7d结束。研究结果表明,与对照组相比,试验组仔猪断奶重平均提高0.62kg,差异极显著(P<0.01);成活率提高4.51%,差异显著(P<0.05);在哺乳和断奶前7d,试验组仔猪腹泻率分别比对照组低1.37%(P<0.05)、2.96%(P<0.01)。因此,蜂胶对提高母猪生产性能有较大促进作用。     

Evidence for plasmid-mediated tetracycline resistance in Paenibacillus larvae, the causal agent of American Foulbrood (AFB) disease in honeybees

Paenibacillus larvae is the causal agent of American Foulbrood (AFB) disease, the most virulent bacterial disease of honeybee (Apis mellifera L.) brood. Oxytetracycline is the main antibiotic used for prevention and control of AFB. Using the polymerase chain reaction, isolates were screened for the presence of the tetracycline resistance tet(K) and tet(L) determinants. Four isolates (5%), which correlated with the Tc-resistant phenotypes, were found to carry the tet(K) determinant, whereas none carried the tet(L) determinant. P. larvae cells were also screened for the presence of extrachromosomal DNA and evidence obtained that tetracycline resistance is plasmid-encoded. A few P. larvae isolates were found to be able to transfer the tet(K) determinant to Bacillus subtilis, suggesting that a conjugation mechanism may be involved in the transfer of the tetracycline-resistant phenotype. Minimum inhibitory concentrations to tetracycline were determined for 75 isolates of P. larvae from different geographical origins and found to range between 0.062 and 128 microg tetracyclineml(-1), with MIC(50) and MIC(90) values of 1 and 4, respectively. According to results from P. larvae populations, isolates could be considered as susceptible when their MICs were <4, intermediate for MICs values 4-8 and resistant for MICs > or = 16. To our knowledge, this is the first report of Tc(r)Paenibacillus species carrying a tet(K) gene, and also the first record of P. larvae strains carrying tet(K) determinants and its correlation with the presence of extrachromosomal DNA.     

Impact of supplementing diets with propolis on productive performance,egg quality traits and some haematological variables of laying hens

One hundred and twenty eight, 28‐weeks‐old Lohmann LSL hybrid layers were used in this experiment, which lasted 12 weeks to investigate the effect of propolis supplementation on the productive performance, egg quality traits and haematological variables of laying hens. All hens were randomly classified into four equal experimental groups, eight replicates (4 birds/each). Hens in group 1 were fed on a commercial diet and considered as control group, while those in groups 2, 3 and 4 were fed on the same commercial diet and supplemented with 250, 500 and 1000 mg propolis/kg diet. The obtained results revealed that daily feed consumption/hen increased insignificantly with increasing propolis level than that of the control group. Regarding the means of egg mass and egg production rate, it was observed that the laying hens fed diets containing 250 and 1000 mg propolis/kg significantly (p < 0.05) produced more and heaver egg in comparison with control group. External egg quality traits have not affected with increasing the level of propolis, while eggshell weight was significantly (p < 0.05) increased. The internal egg quality traits except albumen and yolk percentages increased significantly (p < 0.05) with increasing propolis level for treated hens as compared to those in the control. Concerning the haematological parameters, the results showed that the levels of total protein and globulin increased significantly with increasing propolis level, while cholesterol and liver enzymes were significantly decreased (p < 0.05). Heterophils count of hens in the treated groups significantly decreased, whereas the lymphocyte count significantly increased, resulting in a decreased H/L ratio than that of the control group. Thus, it could be concluded that the supplementation of 250 mg propolis/kg diet is highly recommended to improving egg production, blood constituent and haematological parameters of the commercial laying hens.     

Growth performance,carcass quality,biochemical and haematological traits and immune response of growing rabbits as affected by different growth promoters

The aim of the article was to study the effect of different growth promoters on growth performance, carcass quality, biochemical and haematological traits and immune response of growing rabbits. A total number of 105 male growing NZW rabbits during 35–91 days of age were randomly distributed among 7 groups fed the same basal diet and submitted to different dietary treatments: the first group was unsupplemented and used as control; the other groups were supplemented respectively with bee pollen and/or propolis at 200 mg/kg BW of each and inulin and/or mannanoligosaccharides (MOS) at 35 mg/kg BW of each. Body weight gain, daily feed intake, feed conversion ratio (FCR), biochemical and haematological blood parameters, carcass characteristics, histological studies of ileum and spleen and economical efficiency were measured. Bee pollen administered alone or with propolis significantly (p < 0.01) the body weight gain and improved FCR in respect of the control group. Inulin with MOS significantly improved just FCR than the control group. Bee pollen with propolis and MOS supplemented‐groups resulted in significantly higher (7.96 and 8.41% respectively) white blood cells compared to the control group. Plasma total cholesterol was significantly higher for the MOS group in respect of the control, bee pollen, inulin and inulin with MOS supplemented‐groups. Propolis resulted in significantly higher dressed carcass percentage than the control group and higher carcass index than only bee pollen with propolis supplemented‐group. Bee pollen, in particular if in combination with propolis, could be used as a supplement in the growing rabbits during days 35–91 of age with positive effects on growth rate and feed conversion ratio.     

Immunomodulation by dietary vitamin C in healthy and aflatoxin B1-induced immunocompromised rohu (Labeo rohita)

The aim of this study was to examine the immunomodulatory effect of high levels of dietary vitamin C in healthy and immunocompromised rohu (Labeo rohita) treated with aflatoxin B1 (AFB1). Four groups of rohu were fed experimental diets containing either no vitamin C or supplemented with vitamin C at 500 ppm for 60 days. On the first day of feeding, one group fed the high vitamin C diet and one fed the vitamin C deficient diet, were injected intraperitoneally with a single doses of AFB1 at 1.25 mg kg(-1) body weight. The effect of AFB1 and high dietary vitamin C on specific and non-specific immunity, and disease resistance against Aeromonas hydrophila were examined in the rohu. The ability of vitamin C to counteract immunosuppression induced by AFB1 was also examined. Specific immunity indicated by haemagglutination and haemolysin titres against sheep red blood cells (SRBC), and bacterial agglutination appeared to be unaffected by either the AFB1 treatment or the vitamin C enriched diet. A significant reduction was observed in the non-specific immunity of AFB1-treated fish, however, indicated by lowered bactericidal and lysozyme activities. High dietary vitamin C, on the other hand, enhanced the non-specific immunity of fish, including an enhanced phagocytic ratio and increased serum lysozyme activity. Feeding a high level of dietary vitamin C to AFB1-treated fish increased these parameters to levels similar to those found in control fish. High dietary vitamin C significantly (p < 0.05) enhanced protection against Aeromonas hydrophila infection in both healthy and immunocompromised fish. Results from this study help to establish the beneficial effect of dietary vitamin C on AFB1-induced immunosuppression, as well as confirming the immunostimulatory effect of vitamin C in rohu.     

蜂胶乙醇提取物抗四氧嘧啶对大鼠损伤的效果研究

目的:研究蜂胶乙醇提取物在用四氧嘧啶制造糖尿病大鼠模型过程中的保护作用。方法:对大鼠进行分组。用蜂胶对大鼠进行连续灌胃,30天后,对大鼠注射四氧嘧啶,观察各组大鼠的状态及血糖变化;观察蜂胶对糖尿病大鼠模型的影响。结果:实验前后分别测定各组大鼠的空腹血糖,蜂胶灌胃组跟对照组相比较,蜂胶灌胃组能明显降低大鼠的血糖,蜂胶灌胃组大鼠跟模型组大鼠相比较P<0.01,大鼠状态明显较好;蜂胶能明显降低糖尿病大鼠的血糖。结论:蜂胶能调节血糖,预防和治疗糖尿病。     

Toxicology of aflatoxin B1, warfarin, and cadmium in young pigs: performance and hematology

Observations on the interactions of cadmium (Cd) x aflatoxin B1 (AFB1) and Cd x warfarin included several variables of animal performance and hematology. Cadmium was fed daily for 40 days (groups IV, V, VI) and a Cd-free diet was fed to groups I, II, and III. Groups II and V were treated with AFB1, and groups III and VI were treated with warfarin--each for 5 days during the 5th week of the experiment and the effects were observed for 10 days. All pigs fed the diet with added Cd had developed severe anemia by the 4th week of the experiment. The incorporation of this toxic concentration of Cd (83 micrograms/g) in the diet seemed to have blocked the liver microsomal enzyme system (cytochrome P-450), diminishing the toxic effects of 5 daily oral doses (0.2 mg/kg of body wt) of AFB1 (group V pigs), but enhancing synergistically the toxic anticoagulant effects of the same doses of warfarin in young pigs (group VI). The data presented also indicated that the feeding of toxic concentrations of Cd stimulated increased glutathione peroxidase activity, which conjugated the AFB1 epoxides with their excretion as reduced glutathione but enhanced the toxic anticoagulant effects of warfarin in young pigs.     

不同家蝇幼虫制品对黄羽肉仔鸡营养物质可利用率、肠道菌群和血清生化指标的影响

本研究旨在探讨不同家蝇幼虫制品对黄羽肉仔鸡营养物质可利用率、肠道菌群和血清生化指标的影响。选取 １日龄的黄羽肉仔鸡 ２５２只,随机分成 ７组,每组 ３个重复,每个重复 １２只鸡。对照组饲喂基础饲粮,其余 ６组饲喂分别用 ０．２％、０．５％的家蝇幼虫肽,０．２％、０．５％的家蝇幼虫酶解物,０．２％、０．５％的脱脂家蝇幼虫粉等量替代基础饲粮中鱼粉的试验饲粮。结果表明：１）添加家蝇幼虫肽有提高干物质、粗蛋白质和能量的可利用率的趋势（Ｐ＞０．０５）,且随着添加剂量的增加而提高;添加 ０．５％的家蝇幼虫肽可显著提高粗脂肪、钙、磷和粗灰分的可利用率（Ｐ＜０．０５）。２）添加家蝇幼虫肽可显著提高试验第２周和第４周肠道乳酸杆菌和双歧杆菌的数量（Ｐ＜０．０５）,显著降低大肠杆菌和沙门氏菌的数量（Ｐ＜０．０５）。３）添加家蝇幼虫肽可显著降低试验第 ２周血清谷丙转氨酶活性（Ｐ＜０．０５）和显著提高血清总蛋白含量（Ｐ＜０．０５）,且以０．５％的家蝇幼虫肽组效果最优。在饲粮中添加不同家蝇幼虫制品均能显著降低黄羽肉仔鸡血清尿素氮含量（Ｐ＜０．０５）。由此得出,家蝇幼虫肽具有改善黄羽肉仔鸡肠道菌群、提高营养物质可利用率的作用,且以 ０．５％的添加量效果较好。     

繁奶康对奶牛泌乳早期泌乳性能及血液指标的影响

选择20头荷斯坦高产牛,采用配对分组设计分为对照组和试验组,每组各10头。对照组使用原日粮,试验组产前21d每天在日粮中添加繁奶康125g,于分娩当天添加量增至300g直到试验结束,以探讨日粮添加繁奶康对奶牛泌乳早期产奶性能(产奶量及乳品质)的影响。结果表明,补充繁奶康,产奶量、乳脂校正乳产量试验组明显高于对照组(P0.05);奶牛采食量、乳脂率、乳蛋白率、乳糖率及乳干物质含量两组间差异不显著(P0.05)。血液指标谷草转氨酶、谷丙转氨酶活性两组间无显著差异(P0.05),高产奶牛补充繁奶康对泌乳早期产奶性能有较好的改善作用。     

日粮中添加蜂胶制剂对断奶仔猪生产性能和皮肤颜色的影响

试验旨在研究蜂胶在仔猪上的应用效果。试验采用90头杜×长×大三元杂交仔猪,随机分成对照组、试验1组、试验2组,每组设3个重复,每个重复10头,对照组饲喂基础日粮,试验1组饲喂基础日粮+0.03%蜂胶制剂,试验2组饲喂基础+0.05%蜂胶制剂,试验期为30 d。结果表明,在日粮中添加蜂胶制剂能够明显提高仔猪的生产性能和皮肤颜色,降低仔猪腹泻率。     

Vertical transmission of American foulbrood (Paenibacillus larvae) in honey bees (Apis mellifera)

The mode of transmission between hosts (horizontal versus vertical) of disease agents is important for determination of the evolution of virulence in pathogens. For disease management, it is imperative that the epidemiology of the disease is understood and pathogen transmission rates between hosts is a key factor for this understanding. Surprisingly little is known about transmission rates in honey bee pathology. We have studied the rate of vertical transmission of Paenibacillus larvae, the causative agent of American foulbrood (AFB) in honey bee colonies, as colonies reproduce by colony fission (swarming), by culturing for the spores from repetitive samples of adult bees. The results demonstrate vertical pathogen transmission to daughter swarms. The spore density declines over time in both mother colonies and daughter swarms if mother colonies do not exhibit clinical disease symptoms. Occasional positive samples more than a year post swarming, also in daughter swarms, indicate production of infectious spores from diseased larvae, without clinical disease observable by beekeepers, and/or maintenance of infective spores in the hive environment, allowing both horizontal and vertical transmission to be maintained. The results suggest that the virulence of AFB, being lethal at colony level in contrast to other bee diseases shaped by evolution, could be dependent on apicultural practices and that the pathogen probably would be maintained without causing frequent colony mortality in a natural system.     

类黄酮对蛋鸡生产性能、蛋品质和血液生化特性的影响

试验选用864只39周龄海兰褐蛋鸡,随机分为3个处理,每个处理3个重复,每个重复96只鸡,采用单因素随机试验设计,分别饲喂添加0、30 mg/kg蜂胶黄酮（PF）和6 mg/kg大豆黄酮（DA）的玉米-豆粕型日粮8周。结果表明,日粮中添加PF和DA对蛋鸡产蛋率、破软壳率、料蛋比有改善的趋势;日粮中添加PF和DA能够显著降低蛋黄胆固醇的含量,在蛋保存的第7和14天两者均能不同程度降低蛋黄丙二醛的含量;在试验第4、8周,日粮中添加DA和PF能够显著提高血清HDL水平（P<0.05）,在试验第8周,DA显著降低血清TC和TG水平,而PF显著降低血清TC水平并显著提高血清胰岛素水平（P<0.05）;此外,日粮中添加DA和PF能够显著提高第4周时T、B淋巴细胞转化率（P<0.05）,且添加PF显著提高第8周时T淋巴细胞转化率（P<0.05）。     

黄曲霉毒素B1、复方中药和硒对肉鸡肝组织匀浆中自由基代谢的影响

为观察黄曲霉毒素B1(AFB1)对肉鸡肝组织匀浆自由基代谢的变化,并研究复方中药与硒对AFB1的拮抗效应,将10日龄120只试验肉鸡随机分成4组,每组30只,分别为Ⅰ组(对照组)、Ⅱ组(AFB1组:AFB10.2mg/kgBW)、Ⅲ组(AFB10.2mg/kgBW+亚硒酸钠2mgSe/kgDM)和Ⅳ组(AFB10.2mg/kgBW+复方中药20g/kgDM)。分别处理后于17、24、31、38日龄宰杀5只肉鸡,提取肝组织,检测肝组织中的总抗氧化能力(T-AOC)、总超氧化物歧化酶(T-SOD)活性和过氧化氢酶(CAT)及丙二醛(MDA)含量的变化。结果显示,口服AFB1(0.2mg/kgBW)后T-SOD、T-AOC和CAT活性降低(P<0.05),MDA含量明显升高(P<0.05),而复方中药与硒治疗组T-SOD、T-AOC和CAT活性升高(P>0.05或P<0.05),MDA含量明显下降(P>0.05或P<0.05)。证实,由自由基增多而引起的脂质过氧化损伤在肉鸡AFB1慢性中毒发病机理中起着重要的作用,复方中药与硒均可有效降低脂质过氧化造成的损伤。