Modulation of the in vitro Oxidative Stress and Erythrocyte Cell Membrane Integrity Using Aqueous, Hydroethanolic and Ethanolic Stem-Barks Extracts of Greenwayodendron suaveolens (Engl. & Diels) Verdc

Pneumonia, a respiratory infection induces acute or chronic inflammation, characterized by increased activity of lymphocytes and neutrophils, thus generating oxygen-free radicals that decrease the endogenous antioxidants defence system. The aim of this experimental study focused on the capacity of nontoxic aqueous, hydroethanolic and ethanolic extracts of Greenwayodendron suaveolens (Engl. & Diels) Verdc. subsp. suaveolens to regulate free reactive species and protein inflammation generated by infectious disease. The phytochemical screenings of G. suaveolens extracts were carried out according to precipitation and colorimetric methods. The total antioxidant and flavonoid contents were determined by the Folin-Ciocalteu and Aluminium Chloride ethanolic methods. The efficiency of G. suaveolens extracts on free radicals was evaluated using DPPH•, ABTS+•, and FRAP methods. The anti-inflammatory properties of extracts were evaluated according to in vitro protein (BSA) denaturation, Proteinase Inhibitory Action, and Red Blood Cell Membrane stabilization assays. The G. suaveolens aqueous, hydroethanolic and ethanolic extracts were used for the acute toxicity assessment according to the OECD protocol. The obtained results showed the presence of flavonoids, phenols, polyphenols, tannins, anthocyanins, alkaloids, terpenoids, and sterols as secondary metabolites families in G. suaveolens extracts. The highest contents of total antioxidants and flavonoids were highlighted in the hydroethanolic extract. However, it’s the G. suaveolens aqueous extract that showed the best free radical DPPH• and ABTS+• scavenging activities (SC50) of 11.06 μg/mL and 15.16 μg/mL respectively. The highest ferric-reducing activity was found in G. suaveolens ethanolic extract with 866.23 μg EGA/mg of dry weight. The hydroethanolic extract has shown a high anti-inflammatory activity through BSA denaturation and erythrocyte membrane haemolysis with inhibitory concentrations 50 (IC50) of 48.63 and 59.22 μg/mL respectively. In contrast, proteinase inhibitory activity revealed a better potential of IC50 (34.19 μg/mL) for the ethanolic extract. In oral acute toxicity, all treated groups revealed neither mortality nor any significant alteration in behaviour and locomotion. The lethal dose 50 (LD50) of G. suaveolens extracts was >5000 mg/kg. These results suggest that G. suaveolens stem-barks extracts may serve as therapeutic sources to prevent inflammation induced by oxidative stress, an important feature of infectious diseases.

Study on the Effects of Chinese Herb Additive on Milk Yield and Anti-heat Stress Ability of Holstein Cow

[Objective] The research aimed to explore the effects of Chinese herb additive on milk yield and anti-heat stress ability of Holstein cow.[Method] 36 Holstein cows with similar birth order and milk yield were equally and randomly divided into 3 groups which were control group, Chinese medicine Ⅰ group and Chinese medicine Ⅱ group. In control group, cows were fed with basic feed, while in Chinese medicine Ⅰ group, cows were fed with basic feed containing 4% compound Chinese herb additive and in Chinese medicine Ⅱ group, cows were fed with basic feed containing 3% compound Chinese herb additive.All cows in the 3 groups were analyzed comparatively.[Result] Adding some compound Chinese herb additive into basic feed would increase milk yield and anti-heat stress ability of Holstein cow,besides,it also could decrease cow diseases such as cow mastitis.Chinese medicine Ⅰ would generate the highest economic benefit of practical production.[Conclusion] Adding Chinese herb additive into basic feed is an effective way for reliefing heat stress and increasing milk yield.

Evaluation of Post-operative Anti-stress Response of Dexmedetomidine in Dogs

The stress response, caused by postoperative pain, may have adverse effects on physiological functions of bodies. And, it has been a research priority in veterinary anesthesia that is a method of minimizing the postoperative stress response. The paper aimed to explore the protective effect of dexmedetomidine on stress induced by surgical trauma by studying the effect of dexmedetomidine on the blood glucose, serum cortisol （Cor） and adrenocorticotropic hormone （ACTH） levels in the model of canine stress induced by surgical trauma. Therefore, 32 local healthy female dogs with similar physical conditions, aged from 11.3±2.4 months and meanbody mass （±SD） （7.7±2.2） kg, were randomly divided into four groups： control group DZ （10 min after administration of intramuscular injection of 2 mL normal saline）, group SQY （10 min before administration of intramuscular injection of 20 μg ？ kg-1 dexmedetomidine）, group SHY （10 min after administration of intramuscular injection of 20 μg ？ kg-1 dexmedetomidine） and group DLD （10 min after administration of intramuscular injection of 0.1 mL ？ kg-1 tilidine）. The corresponding drug was sucked out and diluted to 2 mL by saline. The four groups were all excised the uterus and ovaries and established surgical trauma stress model, then given the prescribed dose of the drug on the day of operation, the next day and the 3rd day. Besides, the dogs should be fasted during the days of drug administration. Blood samples were separated and taken to measure, blood glucose, serum Cor and ACTH concentration. The concentration of blood glucose was significantly lower in group SHY than that in group DZ on the day of surgery and the day after surgery （p〈0.05）, besides, it was not obviously different from other two groups. While, the concentration of Cor in group SHY had no significant differences from other three groups （p〉0.05） and was closer to the preoperative values; ACTH concentration in group SHY was significantly different from other three groups on the day of operation （p〈0.05）, and there existed significant difference （p〈0.05） with group DZ on the 2nd day after the operation. The results of analyses showed that 20 μg ？ kg-1dexmedetomidine could decrease the levels of Cor and ACTH in dog serum after operation, which played the role of anti-stress response stimulated by operations.

Effect of flight transport stress on blood parameters in beagles and the anti-stress effect of dangshen

Background: This study investigated the effect of flight transport stress on beagles' routine blood indexes and biochemical parameters and evaluated the anti-stress effect of dangshen(Codonopsis pilosula).Methods: We selected 12 beagles and divided them into two groups. One group was treated with dangshen decoction two hours before the flight, and the other group was untreated. Their routine blood indexes and clinical biochemical parameters were tested and analyzed before transport, after unloading and after adaptation for 1, 2, 3, 4, 5, and 6 days after administering dangshen.Results: We found that flight transportation stress adversely influenced many of the beagles' routine blood indexes. These recovered during adaptation, with dangshen administration assisting recovery of most indexes. Flight transport stress also adversely influenced biochemical indexes in the beagles. Again these recovered during adaptation, and dangshen aided in the recovery.Conclusion: Thus, we found that flight transport adversely affected the beagles' blood indexes, and dangshen reversed the damage from transport stress.

Reducing Dietary Cation-Anion Difference on Acid-Base Balance, Plasma Minerals Level and Anti-Oxidative Stress of Female Goats

Reducing dietary cation-anion difference （DCAD） has been proved an effective way to prevent milk fever in dairy cows. Based on the similar physiological gastro-intestinal tract anatomy and metabolic process between female goats and dairy cows, this study was conducted to evaluate the effects of varying DCAD on fluid acid-base status, plasma minerals concentration and anti-oxidative stress capacity of female goats. Urinary pH, plasma Ca, P and Mg; and anti-oxidative stress indices of total superoxide dismutase （T-SOD）, hydrogen peroxide （HzO2）, glutathione peroxidase （GSH-Px） and malondialdehyde （MDA） were determined to evaluate the effect. Forty-eight Guizhou black female goats （（15±1.9） mon of old, （22.3±3.75） kg of BW） were randomly allocated to 4 blocks of 12 goats each and were fed 1 of 4 diets differed in DCAD level （calculated as Na＋K-C1-S, mEq kg-1 DM）. Levels of DCAD were preliminarily designed to be control （＋ 150 mEq kg^-1 DM, CON）, high DCAD （＋300 mEq kg^-1 DM, HD）, low DCAD （0 mEq kg^-1 DM, LD） and negative DCAD （-150 mEq kg^-1 DM, ND）, respectively. A commercial anionic salts （Animate） and sodium bicarbonate （NaHCO3） were supplemented to reduce and increase DCAD level, respectively. There was no difference in dry matter intake for 4 groups of goats. Urine pH was aggressively decreased （P〈0.0001） with reduced DCAD and there was a strong association between DCAD and urine pH （R2=0.793, P〈0.0001）. Compared with CON and HD feeding of LD and ND resulted in greater （P〈0.05） plasma Ca concentration. Plasma P level was increased （P〈0.05） when anionic salts were supplemented. The DCAD alteration did not affected （P〉0.05） plasma Mg level. There was no significant （P〉0.05） difference in plasma GSH-Px activity and H202, but anionic salts supplementation in LD and ND significantly increased （P〈0.05） plasma T-SOD activity and tended to reduce MDA （P〈0.1） over HD and CON. Results from this study indicated that reducing DCAD could decrease urine pH and increase plasma Ca concentration of female goats. Additionally, reducing DCAD was helpful to enhance anti-oxidative stress capability of female goats.

Role of mitogen activated protein kinase cascade pathway and anti-stress response in liver transplantation

OBJECTIVE: To explore the changes of mitogen activated protein kinase (MAPK) cascade pathway and anti-stress response of hepatocytes after liver transplantation. METHODS: Ten normal liver specimens and 18 punctured donor liver specimens were divided into 3 groups: A (control: 10), B (no rejection: 10) and C (acute rejection:8). MAPK, Ras, Jun and heat shock protein 70 (HSP70) were tested immunohistochemically while Ras and HSP70 were tested by in situ hybridization. All sections were subjected to image analysis. RESULTS: Protein expressions of MAPK, Ras and Jun were increased by an ascending order of groups A, B and C. The protein expression of HSP70 was the highest in group B but lower in group C. Expressions of Ras and HSP7O mRNA were consistent with those of protein. CONCLUSIONS: The changes of the MAPK cascade pathway and anti-stress response of hepatocytes after liver transplantation are one of regulation mechanisms for protecting the hepatocytes from damage after liver transplantation. This mechanism is active to support individual survival.

Pre-Stressed Rope Reinforced Anti-Sliding Pile

Pre-stressed rope reinforced anti-sliding pile is a composite anti-sliding structure. It is made up of pre-stressed rope and general anti-sliding pile. It can bring traditional anti-sliding pile＇s retaining performance into full play, and to treat with landslide fast and economically. The difference between them is that the pre-stressed rope will transfix the whole anti- sliding pile through a prearranged pipe in this structure. The working mechanics, the design method and economic benefit are studied. The results show that the pre-stressed rope reinforced anti-sliding pile can treat with the small and middle landslides or high slopes well and possess the notable advantage of technology and economic.

Effects of Chinese Herb Additive on Milk Yield and Anti-heat Stress Ability of Holstein Cows

[Objective] To explore the effects of Chinese herb additive on milk yield and anti-heat stress ability of Holstein diary cow. [Method] A total of 36 Holstein cows at same parity and with similar milk yield were randomly divided into three groups, namely, control group, Chinese medi- cine group I and Chinese medicine group I1. The cows in the Chinese medicine group I were fed basal diet containing 4% compound Chinese herb additive; those in the Chinese medicine group II were fed basal diet containing 3% compound Chinese herb additive; and those in the control group were fed common basal diet. All cows in the three groups were analyzed comparatively. [Result] Supplementing some compound Chinese herb ad- ditive into basal diet increased milk yield and anti-heat stress ability of Holstein cows, besides, it also decreased cow diseases like cow mastitis. The Chinese medicine group I generated the highest economic benefit of practical production. [ Conclusion] Supplementing Chinese herb additive in- to basal diet is an effective way to relieve heat stress and increase milk yield.

A fractional differential constitutive model for dynamic stress intensity factors of an anti-plane crack in viscoelastic materials

Fractional differential constitutive relationships are introduced to depict the history of dynamic stress inten- sity factors （DSIFs） for a semi-infinite crack in infinite viscoelastic material subjected to anti-plane shear impact load. The basic equations which govern the anti-plane deformation behavior are converted to a fractional wave-like equation. By utilizing Laplace and Fourier integral transforms, the fractional wave-like equation is cast into an ordinary differential equation （ODE）. The unknown function in the solution of ODE is obtained by applying Fourier transform directly to the boundary conditions of fractional wave-like equation in Laplace domain instead of solving dual integral equations. Analytical solutions of DSIFs in Laplace domain are derived by Wiener-Hopf technique and the numerical solutions of DSIFs in time domain are obtained by Talbot algorithm. The effects of four parameters α, β, b1, b2 of the fractional dif- ferential constitutive model on DSIFs are discussed. The numerical results show that the present fractional differential constitutive model can well describe the behavior of DSIFs of anti-plane fracture in viscoelastic materials, and the model is also compatible with solutions of DSIFs of anti-plane fracture in elastic materials.

化学诱变提高植物抗逆性的研究进展

化学诱变是农业上一种传统的育种技术,在植物抗逆育种方面受到育种家的青睐,用于改善植物的抗寒、抗旱、耐盐碱性等育种方面的研究。植物组织培养技术是实现细胞或个体快速繁殖的有效途径。以上两种技术的结合,可有效提高突变的频率,人为扩大植物遗传变异范围。近年来,化学诱变与生物技术结合在植物抗逆诱变育种方面展现出了积极的发展前景,对于植物新品种选育具有重要的实践意义。本研究综述了化学诱变的特点、常用化学诱变剂[主要是甲基磺酸乙酯(EMS)和叠氮化钠(NaN3)]的诱变机制、使用方法、诱变效果以及影响化学诱变的因素等,并介绍了化学诱变在植物抗逆育种领域中的新近研究进展。

奎宁酸的抗氧化活性和神经保护作用研究

奎宁酸是一种小米来源的类黄酮类物质,为探究奎宁酸的神经保护作用,该研究建立了H_(2)O_(2)诱导的SH-SY5Y细胞氧化应激模型,通过MTT法测定奎宁酸对SH-SY5Y细胞活性影响,同时测定了抗氧化酶超氧化物歧化酶(superoxide dismutase,SOD)的活性和氧化应激标志分子谷胱甘肽(glutathione,GSH)、丙二醛(malondialdehyde,MDA)的含量,利用实时荧光定量PCR检测了抗氧化酶和炎症因子表达情况,并用Western blot测定了炎症因子的蛋白表达量。研究结果表明,100μg/mL的奎宁酸处理显著抑制H_(2)O_(2)引起的SH-SY5Y细胞存活率下降;对细胞抗氧化指标的检测显示,奎宁酸处理可以增强细胞SOD的活性,增加GSH的水平并降低细胞的MDA水平,提高SOD、过氧化氢酶(catalase,CAT)、谷胱甘肽过氧化物酶(glutathione peroxidase,GPx)等抗氧化酶基因的表达水平,降低氧化损伤;另外,奎宁酸还可以降低H_(2)O_(2)诱导的SH-SY5Y细胞中炎症因子白介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)的表达水平,减轻SH-SY5Y细胞的损伤。综上,奎宁酸可以通过抑制细胞氧化应激水平、发挥抗炎作用保护神经细胞不被损伤,为进一步探究小米多酚在氧化应激相关疾病中的作用奠定了基础。

构建进化路线的语义要素法

在构建进化路线的过程中,进化节点产生条件以及种类的判别缺乏标准化的客观依据,导致低效率并具有较大的主观盲目性。通过分析进化树组成路线的本质语义要素与递进循环关系,将结果汇总为语义表,得到构建进化路线的语义要素法。语义要素可以作为进化节点产生条件以及种类的判别依据,提高了构建效率,并且判别与表示的标准化有利于成果的客观记录与交流。最后,以海底电缆反应力锥切削装置为例,验证了方法的效率和进步优势。

商陆提取物药理作用研究进展

商陆是我国传统峻下逐水中药,收载于历版《中华人民共和国药典》,入药部位为根部,具有利尿泻下、抗炎、抗肿瘤、祛痰镇咳平喘等药理活性。临床多用于治疗肾炎、肝硬化腹水、乳腺增生、银屑病等疾病。通过对商陆提取物和化学成分药理作用进行总结,为今后商陆深入研究及合理开发利用提供支持和参考依据。

STRESS INTENSITY FACTORS CALCULATION IN ANTI-PLANE FRACTURE PROBLEM BY ORTHOGONAL INTEGRAL EXTRACTION METHOD BASED ON FEMOL

For an anti-plane problem, the differential operator is self-adjoint and the corresponding eigenfunctions belong to the Hilbert space. The orthogonal property between eigenfunctions （or between the derivatives of eigenfunctions） of anti-plane problem is exploited. We developed for the first time two sets of radius-independent orthogonal integrals for extraction of stress intensity factors （SIFs）, so any order SIF can be extracted based on a certain known solution of displacement （an analytic result or a numerical result）. Many numerical examples based on the finite element method of lines （FEMOL） show that the present method is very powerful and efficient.

高水头抽水蓄能电站地应力综合测试及抗劈裂分析

抽水蓄能电站建设处于加速期,合理布置地应力试验和精准获取地应力数据对高水头抽水蓄能电站意义重大。以某高水头抽水蓄能电站为案例,针对高水头抽水蓄能电站地形特点及地应力特征,在不同勘察阶段进行综合地应力测量,同时联合地应力场反演,获取空间三维地应力场分布规律并对围岩进行抗劈裂分析。综合实测结果表明:二维地表深孔结果随埋深梯度有变化,中浅部有应力集中现象,符合高水头抽水蓄能电站的地应力分布特征。三孔交汇法及孔壁应变法的地应力量值及方向吻合,地下厂房和高压岔管部位岩体的最大实测主应力为20.9 MPa,最小主应力为7.0 MPa;岩体以水平应力为主。最大主应力方向集中为NEE向。有利用综合实测结果加强模型精细化进行初始地应力场反演,能较好地反映此类工程的地应力场特征,利于围岩的抗劈裂分析及后续衬砌方案的选择。综合地应力测试对于高水头抽水蓄能的地应力获取具有可行性。可供高水头抽水蓄能电站工程的地应力勘察参考。

斜拉桥施工阶段π型混凝土梁翼缘板裂缝成因分析与防裂措施研究

为了解斜拉桥施工阶段π型混凝土梁翼缘板斜向裂缝成因并制定合理的防裂措施,以某主跨120 m的π型预应力混凝土梁斜拉桥为背景,针对其悬臂施工阶段主梁翼缘板下表面出现斜向裂缝的现象进行分析。采用ANSYS软件建立该桥施工阶段杆系模型与混凝土梁实体模型,分析梁体自重、斜拉索张拉、预应力张拉、混凝土收缩、混凝土水化热作用下主梁翼缘板下表面应力情况。结果表明:梁体自重及斜拉索张拉作用下,翼缘板下表面未出现拉应力;横向及纵向预应力张拉作用下,翼缘板下表面产生一定的拉应力,但未超过混凝土抗拉强度标准值;混凝土收缩作用下,翼缘板下表面产生极小的拉应力,不会引起裂缝;混凝土养护过程中水化热作用下,翼缘板下表面混凝土与周边混凝土存在一定温差,部分测点第一主应力超过混凝土抗拉强度标准值,是开裂的主要原因。针对混凝土水化热作用影响,提出主肋布置冷却水管与翼缘板下方火炉加热并用的防裂措施,建立热流耦合模型分析防裂效果。结果表明:所采用的措施能够改善主梁养护过程中水化热温度场分布,各测点第一主应力均未超过混凝土抗拉强度标准值。

枯草芽孢杆菌和酵母培养物联合添加在断奶仔兔上的应用效果研究

试验旨在研究饲粮中添加枯草芽孢杆菌和酵母培养物,对伊拉肉兔生产性能、养分消化率、血清免疫、抗氧化和抗应激能力的影响。选择396只35日龄、体重为(0.979±0.037)kg健康的断奶伊拉肉兔,按随机区组设计分为4个处理(每个处理11个重复,每个重复9只兔),分别为基础饲粮(对照组)、添加1000 mg/kg枯草芽孢杆菌、添加3000 mg/kg酵母培养物、添加1000 mg/kg枯草芽孢杆菌+3000 mg/kg酵母培养物(联合添加组)。试验期共30 d。结果表明:与对照组相比,饲粮添加3000 mg/kg酵母培养物,可提高断奶仔兔1~15 d平均日增重(ADG),降低料重比(F/G)(P<0.05);联合添加显著提高断奶仔兔16~30 d平均日增重,降低料重比(P<0.05);与对照组相比,3个处理组均可提高断奶仔兔粗蛋白(CP)的表观消化率(P<0.05);饲粮添加3000 mg/kg酵母培养物或与1000 mg/kg枯草芽孢杆菌联用可提高断奶仔兔干物质(DM)和粗脂肪(EE)的表观消化率(P<0.05);联合添加可提高断奶仔兔粗纤维(CF)的表观消化率(P<0.05);与对照组相比,饲粮添加3000 mg/kg酵母培养物或与1000 mg/kg枯草芽孢杆菌联用,可提高断奶仔兔血清总抗氧化能力(T-AOC)、免疫球蛋白M(IgM)和干扰素γ(IFN-γ)含量,降低血清醛固酮和皮质醇的含量以及钾钠比值(P<0.05);与对照组相比,3个处理组均可提高断奶仔兔免疫球蛋白A(IgA)、G(IgG)和血清热休克蛋白70(Hsp70)的含量,降低断奶仔兔血清丙二醛(MDA)的含量(P<0.05);联合添加组断奶仔兔血清溶菌酶含量高于其他组(P<0.05)。由此可见,饲粮添加3000 mg/kg酵母培养物或与1000 mg/kg枯草芽孢杆菌联用,能提高断奶仔兔养分表观消化率,改善免疫力,增强抗氧化能力和抗应激能力,改善生长性能。

复合添加剂对冷季绵羊瘤胃发酵及养分表观消化率的影响

【目的】研究复合添加剂对冷季绵羊瘤胃发酵及养分表观消化率的影响。【方法】选用体重[(39.64±2.72)kg]相近、健康状况良好的6月龄阿勒泰羊公羊60只,随机分为1个对照组和3个复合添加剂组(E_(1)组、E_(2)组、E_(3)组),每组15只羊。对照组饲喂基础饲粮,E_(1)组在基础饲粮中添加2.2%的复合添加剂Ⅰ(沙棘叶粉∶氯化铵∶谷氨酰胺=15∶5∶2),E_(2)组在基础饲粮中添加2.2%的复合添加剂Ⅱ(沙棘叶粉∶氯化铵∶胍基乙酸=15∶5∶1),E_(3)组在基础饲粮中添2.2%的复合添加剂Ⅲ(沙棘叶粉∶氯化铵∶谷氨酰胺∶胍基乙酸=15∶5∶2∶1)。预试期15 d,正试期30 d。【结果】(1)整个试验阶段,E_(1)、E_(2)和E_(3)组的平均日采食量显著或极显著高于对照组(P<0.05或P<0.01);E_(1)和E_(3)组第1~15 d料重比极显著低于对照组(P<0.01)。(2)E_(1)组的乙酸/丙酸显著高于E_(3)组(P<0.05);E_(2)组的异戊酸浓度显著高于对照组(P<0.05);其它瘤胃发酵参数组间差异不显著。(3)E_(1)组的干物质、有机物、粗蛋白、中性洗涤纤维、酸性洗涤纤维及总能的表观消化率最高,极显著高于对照组(P<0.01),E_(2)组粗脂肪的表观消化率最高,极显著高于对照组(P<0.01)。饲粮中添加复合添加剂有助于提高冷季绵羊的养分表观消化率。【结论】复合添加剂Ⅰ(沙棘叶粉∶氯化铵∶谷氨酰胺=15∶5∶2)在冷季绵羊生产中的应用效果较好。

套筒灌浆搭接及对接接头高应力反复拉压试验

为比较套筒灌浆搭接及对接接头间力学性能差异,进行了41个搭接接头和20个对接接头的单拉及高应力反复拉压试验。结果表明:单拉及高应力反复拉压时,两种接头均能实现最大力下总伸长率大于6%、延性系数大于4,强度基本满足规范要求;高应力反复拉压后单拉时,两种接头承载力均有所提高,但接头初始刚度和延性下降;防偏转措施可减少搭接接头残余变形,但其约束刚度有限,搭接接头残余变形略大于对接接头,防偏转搭接接头及对接接头残余变形基本满足规范要求;高应力反复拉压后单拉时,搭接接头套筒中部截面在加载前期纵向受拉、环向受压,加载后期纵向受压、环向受拉,对接接头套筒加载过程中均为纵向受拉、环向受压;高应力反复拉压结束后单拉时,防偏转、不防偏转搭接接头套筒中部截面近钢筋侧最大纵向拉应变分别为对接接头的0.10~0.39倍、0.13~0.18倍,最大环向压应变分别为对接接头的0.09~0.49倍、0.02~0.32倍,搭接接头对套筒材性要求较低;钢筋直径相同时搭接接头材料成本较对接接头降低约35%。

藿香提取物对夏季蛋种鸡产蛋性能、内分泌激素、抗应激能力、抗氧化能力及繁殖性能的影响

本试验旨在探究藿香提取物(ARE)对夏季蛋种鸡产蛋性能、蛋品质、内分泌激素水平、抗应激能力、抗氧化能力和繁殖性能的影响。选取288只65周龄、健康且产蛋率相近的大午金凤蛋种鸡,随机分成4组,每组6个重复,每个重复12只鸡。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加0.05%(0.05%ARE组)、0.10%(0.10%ARE组)和0.15%(0.15%ARE组)藿香提取物的试验饲粮。预试期7 d,正试期49 d。结果显示:1)与对照组相比,0.15%ARE组蛋种鸡第1~49天产蛋率极显著提高(P<0.01),各试验组第1~49天平均日采食量均极显著提高(P<0.01);0.15%ARE组第1~28天料蛋比显著低于0.05%、0.10%ARE组(P<0.05)。2)饲粮添加不同水平藿香提取物对蛋种鸡蛋品质相关指标无显著影响(P>0.05)。3)0.15%ARE组第49天血清中促性腺激素释放激素(GnRH)、雌二醇(E_(2))含量和促卵泡素(FSH)活性极显著高于其他组(P<0.01);0.10%ARE组第28天血清中FSH、促黄体生成素(LH)活性极显著高于对照组和0.05%ARE组(P<0.01)。4)与对照组相比,0.15%ARE组第49天血清中三碘甲状腺原氨酸(T_(3))、四碘甲状腺原氨酸(T_(4))含量显著提高(P<0.05),第28天血清中瘦素(LEP)含量极显著降低(P<0.01)。5)0.15%ARE组第28天血清中皮质酮(CorT)含量极显著低于对照组和0.10%ARE组(P<0.01),各试验组第49天血清中CorT含量极显著低于对照组(P<0.01);0.15%ARE组第28天和第49天血清中热休克蛋白70(HSP70)含量显著降低(P<0.05)。6)0.10%ARE组第28天血浆中总超氧化物歧化酶(T-SOD)活性和总抗氧化能力(T-AOC)极显著高于其他组(P<0.01);与对照组相比,各试验组第49天血浆中T-SOD活性极显著提高(P<0.01),丙二醛(MDA)含量显著降低(P<0.05)。7)0.05%ARE组种蛋受精率显著高于对照组和0.10%ARE组(P<0.05);与对照组和0.05%ARE组相比,0.15%ARE组种蛋死胚率显著降低(P<0.05),母鸡提供的健雏率显著提高(P<0.05)。综上所述,在饲粮中添加藿香提取物可以通过提高夏季蛋种鸡的抗应激能力和抗氧化能力来提高机体健康水平,同时可以调整机体内分泌,进而提高夏季蛋种鸡的产蛋性能和繁殖性能,并且本试验中以0.15%藿香提取物的应用效果最佳。