How Does Heat-Stress Intensity Affect the Stability of Microbial Activity and Diversity of Soil Microbial Communities in Outfields and Homefields’ Cultivation Practices in the Senegalese Groundnut Basin?

Agroecosystems in the Senegalese groundnut basin experience long periods of high temperatures and drought, which disrupt the stability of soil microbial communities. This study evaluated how that stability is affected by homefields and outfields’ agricultural practices and the duration of heat stress. Specifically, we collected soils from organically farmed fields that receive continual high inputs of manure (homefields), and from fields that are rarely manured (outfields). Soil samples were submitted to artificial heat stress at 60°C for 3, 14, and 28 days, followed by 28 days of recovery at 28°C. We examined the functional stability of microbial communities by quantifying C mineralization, and characterized the stability of the communities’ taxonomic compositions via high-throughput DNA sequencing. We found that the microbial communities have a low resistance to heat stress in soils from both types of fields. However, the manuring practice does affect how the functional stability of microbial communities responds to different durations of heat stress. Although functional stability was not recovered fully in either soil, microbial community resilience seemed to be greater in homefield soils. Differences in manuring practices also affected the structural taxonomic stability of microbial communities: relative abundances of Bacilli, Chloroflexia, Actinobacteria and Sordariomycetes increased in the homefield stressed-soils, but decreased significantly in outfield soils. In contrast, relative abundances of α-Proteobacteria, γ-Proteobacteria and Eurotiomycetes increased significantly in outfield stressed-soils, while decreasing significantly in the homefield soils. Relative abundances of Bacilli changed little in outfield soils, indicating that this taxon is resistant to heat stress. In summary, the microbial communities’ capacities to resist heat stress and recover from it depend upon the organic richness of the soil (i.e., manuring practice) and the adaptation of soil microbes to environmental conditions.

Physiological and Biochemical Effects of 24-Epibrassinolide on Heat-Stress Adaptation in Maize (Zea mays L.)

Brassinosteroids (BRs) are a family of about 70 structurally related polyhydroxy steroidal phytohormones that regulate a number of physiological processes in plants. Among these, brassinolide (BL), 28-homobrassinolide (28-homoBL) and 24-epibrassinolide (24-EpiBL) are more common. The present study aims at studying the usefulness of 24-epiBL in ameliorating the impacts of heat-stress in maize along with its role in regulating cellular antioxidant defense system. Maize hybrid PMH 3 was grown in pots in a green house maintained at 14 hours day (25℃)/10hours night (17℃). A solution of 24-epiBL (1 μM) was applied externally at V4 stage. Leaf tissues were sampled from both treated and control plants. Subsequently, both the groups of pots were placed in plant growth chamber maintained at high temperature (48℃;RH 50%). Plants were sampled for biochemical analysis after 3, 6, 9, 24 and 48 hours of high temperature exposure. Exogenous application of 24-EpiBL arrested protein degradation and enhanced cell membrane stability, as compared to the control. The biochemical activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD) and peroxidase (POX) were found to be dynamically and variably modulated post 24-epiBL treatment. Thus, the study supports the role of BRs as anti-stress agents.

Effects of Compound Acidifier on Growth Performance and Serum Biochemical Parameters of Heat-stressed Wenchang Chickens

[Objective]The paper was to investigate the effects of compound acidifier on growth performance and serum biochemical parameters of heat-stressed Wenchang chickens.[Method]A total of 28881-day-old Wenchang chickens with the same genetic background and similar initial weight(985.63±20.35 g)were randomly divided into four groups,four replicates per group and 18 chickens per replicate.Birds were fed the basal diet supplemented with 0 g/kg(control group),1 g/kg(groupⅠ),2 g/kg(groupⅡ)and 3 g/kg(groupⅢ)compound acidifier.The trial lasted 35 d.[Result]The daily gain of experimental groupⅠwas significantly higher than those of control group and groupⅢ(P<0.05),and the feed intake of experimental groupⅠwas also markedly higher than that of control group(P<0.05),but the feed gain ratio of experimental groupⅠwas significantly lower than that of groupⅢ(P<0.05).Compared with control group,the serum total protein and albumin levels of experimental groupⅠincreased(P>0.05),but the serum uric acid concentration decreased(P>0.05).[Conclusion]Supplementing 1 g/kg compound acidifier could improve the growth performance of heat-stressed Wenchang chickens.

Milk production and composition and metabolic alterations in the mammary gland of heat-stressed lactating dairy cows

This experiment was conducted to investigate the effects of heat stress(HS) on the feed intake, milk production and composition and metabolic alterations in the mammary gland of dairy cows. Twenty Holstein cows were randomly assigned to one of two treatments according to a completely randomized design. Half of the cows were allocated to the HS group in August(summer season), and the other half were assigned to the HS-free group in November(autumn season). HS reduced(P<0.01) dry matter intake(DMI), milk yield, milk protein and milk urea nitrogen(MUN) of cows compared with HSfree control, but increased(P<0.01) milk somatic cell counts(SCC). We determined the HS-induced metabolic alterations and the relevant mechanisms in dairy cows using liquid chromatography mass spectrometry combined with multivariate analyses. Thirty-four metabolites were identified as potential biomarkers for the diagnosis of HS in dairy cows. Ten of these metabolites, glucose, lactate, pyruvate, lactose, β-hydroxybutyrate, citric acid, α-ketoglutarate, urea, creatine, and orotic acid, had high sensitivity and specificity for HS diagnoses, and seven metabolites were also identified as potential biomarkers of HS in plasma, milk, and liver. These substances are involved in glycolysis, lactose, ketone, tricarboxylic acid(TCA), amino acid and nucleotide metabolism, indicating that HS mainly affects lactose, energy and nucleotide metabolism in the mammary gland of lactating dairy cows. This study suggested that HS might affect milk production and composition by affecting the feed intake and substance metabolisms in the mammary gland tissue of lactating dairy cows.

Effects of Bupleurum extract on blood metabolism, antioxidant status and immune function in heat-stressed dairy cows

This experiment was conducted to evaluate the effects of Bupleurum extract （BE） on blood metabolites, antioxidant status, and immune function in dairy cows under heat stress. Forty lactating Holstein cows were randomly assigned to 1 of 4 treatments. The treatments consisted of 0, 0.25, 0.5, and 1.0 g of BE kg-1 dry matter. Supplementation with BE decreased （P〈0.05） blood urea nitrogen （BUN） contents and increased blood total protein （TP） and albumin （ALB） levels compared with control cows, but it had no effects （P〉0.05） on blood glucose （GLU）, nonesterified fatty acid （NEFA）, total triglycedde （TG）, low-density lipoprotein cholesterol （LDL-C）, and high density lipoprotein cholesterol （HDL-C）. Compared with control cows, cows fed BE had higher （P〈0.05） superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） activity. However, supplementation with BE had no effect （P〉0.05） on total antioxidant capacity （T-AOC） or malondialdehyde （MDA） levels. The immunoglobulin （Ig） A and G contents increased （P〈0.05） in cows fed 0.25 or 0.5 g of BE kg-1. Interleukin （IL）-2 and IL-4 levels were higher （P〈0.05） in cows fed 0.5 and 1.0 g of BE kg-1, and IL-6 was significantly elevated （P〈0.05） in cows fed 0.5 g of BE kg-1. There were no treatment effects （P〉0.05） on the CD4＋ and CD8＋ T lymphocyte ratios, CD4＋/CD8＋ratio, or tumor necrosis factor-α （TNF-α） level among the groups. These findings suggest that BE supplementation may improve protein metabolism, in addition to enhancing antioxidant activity and immune function in heat-stressed dairy cows.

Predicting heat-stressed EEG spectra by self-organising feature map and learning vector quantizers——SOFM and LVQ based stress prediction

Self-Organising Feature Map (SOFM) along with learning vector quantizers (LVQ) have been designed to identify the alterations in brain electrical potentials due to exposure to high environmental heat in rats. Three groups of rats were considered—acute heat stressed, chronic heat stressed and control groups. After long EEG recordings following heat exposure, EEG data representing three different vigilance states such as slow wave sleep (SWS), rapid eye movement (REM) sleep and AWAKE were visually selected and further subdivided into 2 seconds long epoch. In order to evaluate the performance of artificial neural network (ANN) in recognizing chronic and acute effects of heat stress with respect to the control subjects, unsupervised learning algorithm was applied on EEG data. Mean performance of SOFM with quadratic taper function was found to be better (chronic-92.6%, acute-93.2%) over the other two tapers. The effect of LVQ after the initial SOFM training seems explicit giving rise to considerable improvements in performance in terms of selectivity and sensitivity. The percentage increase in selectivity with uniform taper function is maximum for chronic and its control group (4.01%) and minimum for acute group (1.29%) whereas, with Gaussian it is almost identical (chronic-2.57%, acute-2.03%, control- 2.33%). Quadratic taper function gives rise to an increase of 2.41% for chronic, 1.96% for acute and 2.91% for control patterns.

Overall Performance, Carcass Yield, Meat Safety Potentials and Economic Value of Heat-Stressed Broilers Fed Diets with Balanced Electrolytes

Tropical regions across the globe are characterized by an annually prolonged hot weather conditions that showcase limiting production efficiency in livestock industry, as domesticated animals leave the zone of maximum comfort, under heat stress, with death and reduced carcass yield accompanying the subsequent alteration in body chemistry and behavior. However, pen house orientation, cooling systems, genetic modification and different dietary manipulations have been employed in poultry industry, but many of such did not account for the body’s acid-base equilibrium and the potentials of aggregate levels of dietary electrolytes in enhancing carcass yield of broilers under severe heat stress conditions. Therefore, this study was conducted to investigate the effects of different electrolyte-balanced diets on overall performance, carcass yield, meat safety potentials and economic value of heat-stressed broilers reared for five weeks. Arbor Acre broiler chicks (n = 300) were randomly allotted to diets with aggregate electrolyte balance of 210 (T1), 240 (T2), 270 (T3), 300 (T4), 330 (T5) and 360 (T6) mEq/Kg, in a completely randomised design. On day 35, birds whose weights were closest to the mean class weight were selected from each replicate pen for carcass yield assessment. Also, data on performance and cost-benefit analysis were analysed using descriptive statistics and ANOVA at α = 0.05. Electrolyte-balanced diets though contained salts that presumably could have improved satiety, yet they do not enhance appetite in heat-stressed broilers. However, dietary protein efficiency was enhanced at an electrolyte balance levels of 240 and 270 mEq/kg, which translated into increased body weight gain. Weights of primal parts of birds on 270 mEq/kg DEB were highest at 35 days. Feed cost values (per kilogram weight gain) of rations with 240 mEq/kg and 270 mEq/kg DEB were lower and showcased promising economic buoyancy to both rural and commercial poultry farmers, while ensuring a high food safety standard under tropical conditions.

百香果果壳提取物对热应激小鼠的保护作用

为研究百香果果壳提取物对热应激小鼠的保护作用,本试验选取健康清洁级ICR雄性小鼠40只,随机分为对照组、热应激组、低剂量组和高剂量组共4个组,每组10只。所有小鼠饲喂基础颗粒饲料,正常饮水。低剂量组和高剂量组分别按100和200 mg/(kg·bw·d)剂量灌胃百香果果壳提取物,对照组和热应激组小鼠每天灌胃等量生理盐水。持续灌胃14 d后,除对照组外,其余3个组小鼠每天热处理2 h,连续7 d,期间持续给药。试验结束时,空腹称量小鼠体重;分析小鼠体重变化;采集血液检测血清中谷氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、肌酐(Cr)、尿素氮(BUN)和热休克蛋白70(HSP70)生化指标,以及肿瘤坏死因子α(TNF-α)、白介素6(IL-6)、白介素2(IL-2)和γ干扰素(IFN-γ)细胞因子含量;收集小鼠肝脏和肾脏,观察其组织病理学变化。结果显示,热应激结束后,4个组小鼠体重无显著差异(P>0.05),但热应激组减重最多;与对照组比较,热应激组血清生化和细胞因子各指标均显著升高(P<0.05);与热应激组相比,低剂量组和高剂量组小鼠血清生化和细胞因子各指标均显著降低(P<0.05),小鼠肝脏和肾脏组织损伤有所减轻,且高剂量组优于低剂量组。结果表明,百香果果壳提取物对热应激小鼠具有一定的保护作用。

中药添加剂对热应激生长兔生长性能、屠宰性能、肠道微生态和血清生化指标的影响

本试验旨在研究饲粮中添加中药添加剂对热应激生长兔生长性能、屠宰性能、肠道微生态和血清生化指标的影响。选取48只健康、体重相近的2月龄新西兰白兔,随机分成2组,每组24只(公母各占1/2),单笼饲养。在夏季热应激状态下,对照组饲喂基础饲粮,中药组在基础饲粮中添加1%中药添加剂。预试期7 d,正试期42 d。结果表明:1)对照组和中药组之间末重、平均日增重和料重比差异不显著(P>0.05)。中药组的成活率较对照组有所增加(83.3%vs.70.8%,P>0.05)。2)中药组的半净膛重和半净膛率显著高于对照组(P<0.05)。3)中药组的盲肠内容物干物质含量显著高于对照组(P<0.05),盲肠内容物乙酸和丙酸含量有低于对照组的趋势(P=0.092)。4)对照组和中药组之间盲肠内容物细菌总数和alpha多样性差异不显著(P>0.05)。中药组的盲肠内容物栖粪杆菌属、普氏栖粪杆菌相对丰度显著高于对照组(P<0.05),盲肠内容物阿克曼菌属和大肠杆菌相对丰度有高于对照组的趋势(P=0.080、P=0.088)。5)中药组的粪便球虫圆小囊数有低于对照组的趋势(P=0.082)。6)对照组和中药组之间血清生化指标差异不显著(P>0.05)。综上所述,饲粮中添加中药添加剂可调控热应激生长兔肠道微生态,提高屠宰性能和肠道健康。

铬对奶畜热应激的调控作用及其研究进展

随着奶畜养殖业集约化程度的不断提高,如何避免热应激对奶畜养殖业乃至畜牧业造成重大的影响成为集约化牧场亟待破解的难题之一。热应激会引起动物生产性能、免疫力及繁殖性能下降等一系列变化。研究发现,微量元素铬(Chromium,Cr)对热应激引起的多种不良反应有抑制作用,从而减轻对动物机体的危害。本文结合了国内外学者对铬在奶畜热应激下的作用研究,综述了铬对奶畜热应激的调控作用及其研究进展。

热处理对选区激光熔化Al-Mn-Mg-Sc-Zr合金力学性能和腐蚀行为的影响

以Al-4.77Mn-1.37Mg-0.67Sc-0.25Zr(质量分数,%)合金粉末为原料,在激光功率330 W和扫描速率700 mm/s下进行选区激光熔化(Selective laser melting,SLM)形成SLM Al-Mn-Mg-Sc-Zr合金,结合慢应变速率拉伸实验、电化学测试、析氢浸泡实验及显微组织表征手段,分析了(350℃,8 h)热处理对SLM Al-Mn-Mg-Sc-Zr合金力学性能和腐蚀行为的影响。结果表明:SLM Al-Mn-Mg-Sc-Zr合金力学性能优异,抗拉强度、屈服强度和伸长率分别为423 MPa、376 MPa和25.1%。热处理后,SLM Al-Mn-Mg-Sc-Zr合金晶内析出大量针棒状纳米Al_(6)Mn相,抗拉强度和屈服强度分别提升至509 MPa和478 MPa。此外,SLM Al-Mn-Mg-Sc-Zr合金具有良好的耐蚀性能,热处理可以促进SLM Al-Mn-Mg-Sc-Zr合金的钝化,在-0.5 V极化电位时出现钝化台阶,降低SLM Al-Mn-Mg-Sc-Zr合金的电流密度,增加SLM Al-Mn-Mg-Sc-Zr合金的阳极极化率,使SLM Al-Mn-Mg-Sc-Zr合金的平均析氢速率从0.242 mL/(cm^(2)·h)降至0.216 mL/(cm^(2)·h),应力腐蚀敏感因子从3.379%降至0.405%。与此同时,热处理也促进了晶内微米富Si相以及晶界富Mn相和Mg相的析出,增加了SLM Al-Mn-Mg-Sc-Zr合金点蚀形核位置,增大了SLM Al-Mn-Mg-Sc-Zr合金的晶界电化学成分非均匀性,降低了SLM Al-Mn-Mg-Sc-Zr合金的点蚀和晶间腐蚀抗力。

雾水葛总黄酮的提取工艺优化及其对线虫应激能力的影响

目的 正交法优化雾水葛总黄酮的提取工艺,探究其对秀丽隐杆线虫抗应激能力的影响。方法采用NaNO_(2)-Al(NO_(3))_(3)-NaOH显色法测定雾水葛中总黄酮的质量分数,以雾水葛总黄酮提取率为指标,通过单因素考察及正交试验考察时间、温度、料液比、乙醇体积分数对总黄酮提取率的影响,优选出最佳提取工艺。设立给药组和空白组,通过观察线虫头摆动次数、H_(2)O_(2)氧化应激、抗热应激试验探究总黄酮对秀丽隐杆线虫抗应激能力的影响。结果最佳提取工艺:提取时间为40 min,提取温度为70℃,乙醇体积分数为60%,料液比为1∶40 (g∶mL),总黄酮提取率实测值为1.31%。给药组线虫头摆动次数明显多于空白组(P<0.01)。雾水葛总黄酮质量浓度为0.300 mg/mL时,给药组在氧化应激和热应激实验中平均寿命比空白组分别延长32.28%、42.96%。结论超声法操作简单、便捷、提取率高,提取所得总黄酮能增强秀丽隐杆线虫应激能力。

热应激对奶牛胚胎发育影响的研究进展

热应激是限制奶牛生产的一个主要因素,严重影响奶牛胚胎发育,显著降低奶牛的繁殖性能。随着全球变暖加剧和规模化养殖水平的提高,热应激对奶牛繁殖的负面效应越来越突出。文章从内分泌、卵母细胞成熟、早期胚胎质量和胎儿健康等方面阐述了热应激对奶牛胚胎发育的影响,期望为提高奶牛繁殖效率提供参考。

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。

奶牛对热应激的适应性机制及牧场缓解热应激策略

热应激是限制奶牛生产最重要的因素之一,它对奶牛的生产力、健康、繁殖和整体福利都会产生重大影响,并且随着热应激程度的加深对奶牛造成致命性影响。全球变暖加剧了热应激的负面影响。动物会通过改变其表型和生理特征来应对不断变化的环境,动物的生存能力通常取决于其应对或适应现有条件的能力。奶牛是恒温动物,通过减少代谢热量产生与体温调节等来应对并适应热应激,但这会以牺牲掉部分生产性能为代价。本文综述了热应激对奶牛泌乳性能的影响、热应激下泌乳性能降低的原因、奶牛对热应激的适应机制以及牧场应对热应激的策略,为奶牛热应激的研究及生产中改善奶牛热应激等提供参考。

基于TMT蛋白组学分析姜黄素对热应激蛋鸡肝脏抗氧化性能的影响

[目的]本试验旨在研究日粮添加姜黄素对由热应激引起的蛋鸡肝脏抗氧化性能损伤的影响。[方法]以南京盘滁机械化养鸡场提供的180只280日龄海兰蛋鸡为研究对象,随机分成3组:对照组(Con)饲喂基础饲粮,环境温度为(24±2)℃;热应激组(HS)是基于对照组的基础上每天维持热应激6 h以上,环境温度为(34±2)℃;姜黄素组(HS+CUR)是在热应激组的基础上,饲喂基础饲粮中添加150 mg·kg^(-1)姜黄素的试验饲粮;每组4个重复,每个重复15只鸡。采集蛋鸡肝脏组织样利用TMT(tandem mass tags)蛋白质组学技术分析蛋鸡肝脏蛋白质差异表达。[结果]实时荧光定量PCR结果显示:热应激组与对照组相比肝脏SOD1和GPX1的表达极显著降低(P<0.01),CAT表达水平显著降低(P<0.05);添加姜黄素可以极显著增加肝脏SOD1和GPX1表达水平(P<0.01),显著增加CAT表达水平(P<0.05)。TMT蛋白组学分析共检测到5 039个蛋白,其中4 235个具有定量信息,差异表达蛋白主要参与脂质和葡萄糖代谢、氧化应激、线粒体功能障碍和炎症反应等生物进程;主要参与的途径有PPAR信号通路、过氧化物酶体、脂质代谢、细胞色素P450、生物合成以及脂肪细胞因子信号通路等。选取15个显著表达的蛋白进行基因水平上的验证,结果表明基因水平和蛋白组学分析结果一致。[结论]补充姜黄素可以缓解蛋鸡由热应激引起的肝脏氧化应激以及与脂质代谢相关生物学过程。

不同水稻品种苗期叶片生理特性对高温胁迫的响应

【目的】系统研究高温胁迫对水稻苗期叶片生理特性的影响及其与水稻品种耐热性的关系,为制定耐热水稻品种的育种策略提供科学依据。【方法】以8个籼稻品种和8个粳稻品种为材料,在苗期设置对照(白天(07:00-19:00)28℃,夜晚(19:00-07:00)22℃,CK)和高温胁迫(白天(07:00-19:00)42℃,夜晚(19:00-07:00)35℃,HS)2种处理方式,根据幼苗存活率将供试品种分为高抗、中抗、敏感和高度敏感4个耐热性等级,研究高温胁迫对不同耐热性水稻品种苗期叶片的相对含水量、叶绿素含量、活性氧(ROS)积累、质膜损伤、抗氧化酶活性、渗透调节物质和内源激素含量的影响。【结果】高温胁迫下,东稻4号、湘两优2号、黄华占和长白9号的幼苗存活率较高,是苗期耐热性高抗品种;湘两优900、泰优390、郑旱6号、武运粳21、粤王丝苗和吉粳515是苗期耐热性高度敏感品种。与CK相比,HS处理导致苗期水稻叶片的相对含水量、叶绿素含量及内源IAA、Z+ZR和GA_(3)含量下降,ROS积累、质膜损伤(MDA含量和相对电导率)、抗氧化酶(SOD、POD、CAT和APX)活性、渗透调节物质(脯氨酸和可溶性糖)含量和内源ABA含量升高。高温胁迫下,耐热性水稻品种苗期叶片的相对含水量,叶绿素含量,SOD、POD和CAT活性及内源ABA含量均显著高于热敏感品种,ROS含量、相对电导率和MDA含量显著低于热敏感品种,APX活性、渗透调节物质含量及内源IAA、Z+ZR和GA_(3)含量无显著差异。高温胁迫下,水稻苗期叶片ROS积累量、抗氧化酶活性、质膜损伤程度和内源ABA含量与水稻苗期的存活率极显著相关,可作为耐热水稻品种筛选的参考评价指标。【结论】高温胁迫诱导水稻叶片ROS过量积累,引发氧化胁迫是导致叶片枯萎的重要原因,提高抗氧化防御能力和内源ABA信号通路是水稻抵抗高温胁迫的重要途径,可作为耐高温水稻种质资源的重要育种策略。

热应激对鸡肠道屏障的影响及损伤机制研究进展

热应激通过上调皮质醇激素,升高血清内毒素含量,上调肠道内炎症、氧化、凋亡水平增加肠道通透性,最终引发机体系统性炎症反应综合征(SIRS)、多器官功能障碍(MODS),给养殖业造成损失。近年来全球温度持续上升,热应激造成的畜牧业损失引起广泛关注。本文总结了热应激影响鸡生产性能、肠道形态结构、肠道屏障功能(包括炎症反应、氧化应激、凋亡水平)的相关研究及机制,旨在为防治家禽高温应激提供理论参考。

水稻开花期高温热害响应机理及其调控技术研究进展

近年来,频繁发生的极端高温天气严重影响了水稻的生长发育、产量及稻米品质形成。水稻开花期对高温最为敏感,研究花期高温诱导小穗败育机理及其调控措施对减缓水稻高温热害,保障我国粮食安全生产具有重要意义。本文综述了高温下水稻颖花开放、花药开裂及散粉、柱头花粉粒萌发及花粉管伸长的特征及其作用机制,探究水稻花期耐热性调控机制以及减缓水稻花期高温热害的栽培调控措施,不仅为水稻花期高温热害机理及防控技术研究提供新的研究思路,还对今后的研究方向进行了展望。

热应激对金定鸭生产性能、生殖激素水平及免疫指标的影响

试验旨在研究热应激对金定鸭生产性能、血液生殖激素、卵巢生殖相关基因表达量及免疫指标的影响。试验选用产蛋期400日龄的金定鸭,设置对照组(常温组)、试验组(热应激)。对照组环境温度(25±2)℃,试验组环境温度(35±2)℃;测定热应激下金定鸭生产指标、血清生殖激素指标和免疫指标、卵巢生殖基因表达量。结果显示:与对照组相比,试验组产蛋率、总蛋重和平均蛋重极显著降低(P<0.01);血清促卵泡生成素(FSH)含量显著降低(P<0.05);卵巢促性腺素释放激素(GnRH)基因表达量显著降低(P<0.05),促黄体生成素(LH)基因表达量极显著降低(P<0.05);血清IgG含量极显著降低(P<0.01),肿瘤坏死因子-α(TNF-α)含量显著升高(P<0.05)。由此可见,热应激对金定鸭生产性能、生殖激素水平及免疫指标产生不利影响,其中产蛋率、总蛋重、平均蛋重、血清FSH及卵巢LH、GnRH基因表达量均显著降低,蛋鸭炎性因子水平显著增加,机体免疫力显著下降。