Effect of heat stress on early embryonic development in the beef cow

Hereford and Hereford X Angus cows (n = 31) were utilized to determine the effects of heat stress on early embryonic development and survival. After acclimation to handling, cows were cannulated via the jugular vein on d 7 and assigned to either a control (C) chamber environment of 22 C, 35% relative humidity (RH) or one of two heat stress treatments. Ambient temperature was maintained at 37 C for 12 h followed by a decrease to 33 C for the remainder of the day in both treatment groups. Relative humidity was maintained at 27% in treatment 1 (TRT 1) and 38% in treatment 2 (TRT 2). On d 8 to 16, daily measurements of respiration rate (RES), rectal temperature (REC) and water intake were taken along with samples of blood, which were analyzed for hematocrit (HEM) and plasma concentration of protein (PP), progesterone (P4), estradiol-17 beta (E2), thyroxine (T4) and glucose (GLU). The uterus was recovered and flushed with saline on d 17 to recover the conceptus and uterine contents. Conceptus (if present) and corpus luteum (CL) wet weight were determined. Cows subjected to TRT 2 had increased RES and REC (P less than .01), while HEM was decreased (P less than .05) compared with C cows. Plasma T4 concentration was decreased (P less than .10) in TRT 2 compared with TRT 1 and cows, while P4 concentration were not significantly different. Corpora lutea wet weights were reduced (P less than .10) in heat-stressed cows vs C cows.(ABSTRACT TRUNCATED AT 250 WORDS)     

交感神经对小鼠妊娠早期血清中性激素的影响

本文运用交感神经阻断剂6-OHDA(100 mg/kg体重)腹腔注射昆明系小鼠,研究交感神经对妊娠早期外周血清性激素水平的影响.结果显示:交感神经损毁后,妊娠早期外周血清中雌二醇浓度着床前(E3)升高明显,着床期下降;血清中孕酮浓度着床前升高,着床后降低.结论:交感神经通过调控妊娠早期外周血性激素的生理水平,从而维持妊娠的发生,促进妊娠早期胚胎发育.     

卵母细胞质移植对兔原核胚体外发育的影响

卵母细胞胞质中存在着大量的母源性信息，正常受精卵的发育启动和早期卵裂主要由这些母源性信息所控制。为了评估卵胞质含量对早期胚胎发育的影响，以假显微注射兔原核胚为对照，采用显微注射技术将兔原核期胚胎去除或增加一定量的细胞质：试验一，增加5％和20％的细胞质；试验二，移入5％小鼠MⅡ期卵母细胞胞质。胚胎经显微操作后进行R1／R2序贯培养。结果显示，（1）增量5％组胚胎的2细胞胚（72．00％）、8细胞胚（60．00％）、桑椹胚（58．00％）和囊胚（54．00％）的发育率均显著（P〈0．05）高于增量20％组胚胎（分别为47．62％、35．71％、33．33％和30．95％），但与对照组之间无显著差异（P〉0．05）；囊胚细胞数在2个增量组和对照组3者之间也无显著差异（P〉0．05）。（2）将5％小鼠MⅡ期卵胞质移入兔原核胚后，各阶段胚胎发育率和囊胚细胞数与增量5％组、对照组相比均无显著差异；早期胚胎经PCR检测，在2细胞胚（5／5）、8细胞胚（5／5）和桑椹胚（5／5）均全部检测到了供体小鼠mtDNA的D—loop区3’端片段，而在囊胚却仅有1枚（1／5）能够检测到。结果表明，增加少量细胞质不会对兔原核胚的体外发育造成显著影响，但胚胎发育率随着细胞质体积的增加有下降趋势，而异种卵胞质对兔原核胚的发育没有明显影响，在囊胚期虽仍能检测到异种卵胞质中mtDNA的存在，但异种mtDNA会随胚胎发育而逐渐减少。     

Effects of purple sweet potato anthocyanins on development and intracellular redox status of bovine preimplantation embryos exposed to heat shock

The development of cleavage stage preimplantation embryos is disrupted by exposure to heat shock, such as high temperatures in the summer season. In this study, we investigated whether addition of anthocyanins, which are strong scavengers of reactive oxygen species (ROS), improves development and intracellular redox status of heat-exposed bovine preimplantation embryos by reduction of heat shock-derived oxidative stress. After in vitro fertilization (IVF), embryos were cultured at 38.5 C through Day 8 (Day 0=day of IVF) with 0, 0.1, 1 and 10 microg/ml anthocyanins (non-heat-shocked group). On Day 2, embryos were cultured at 41.5 C for 6 h with 0, 0.1, 1 and 10 microg/ml anthocyanins followed by culture at 38.5 C until Day 8 (HS group). After exposure to heat shock, the intracellular ROS and glutathione (GSH) contents of individual embryos were measured in the non-heat-shocked and HS groups using fluorescent probes. On Day 8, the blastocysts formation rates of the embryos and total cell numbers of blastocysts were evaluated. Embryos exposed to heat shock without anthocyanins showed a significant decrease in blastocyst formation rate and GSH content (P<0.05) and an increase in intracellular ROS (P<0.05) compared with non-heat-shocked embryos. In contrast, addition of 0.1 microg/ml anthocyanins significantly (P<0.05) improved the blastocyst formation rate of the heat-shocked embryos. Addition of any dose of anthocyanins produced a significant decrease in the ROS levels (P<0.05) and tended to increase the GSH levels under heat-shock conditions. However, addition of higher concentrations (1 and 10 microg/ml) of anthocyanins to the culture media under heat shock did not improve the development of embryos. These results indicate that anthocyanins maintain the intracellular redox balance of heat-shocked bovine embryos by reducing intracellular oxidative stress and increasing the GSH levels. Thus, alterations of the redox state using natural antioxidative polyphenols is a useful approach for reducing heat shock-derived oxidative stress.     

交感神经对小鼠排卵和早期胚胎发育的影响

为了研究交感神经对妊娠的调控作用,给小鼠连续5 d腹腔注射交感神经化学损毁剂——6-OHDA(100 mg/kg),将交感神经化学性损毁,然后通过阴道涂片法和显微解剖的方法,对交感神经损毁后小鼠发情周期的变化、排卵的数量和妊娠发生后胚胎数量及大小进行了观察。结果表明:交感神经化学损毁后发情周期和排卵的数量没有明显的变化,但是胚胎的数量明显减少,小鼠胚胎数量在妊娠第7天比对照组同期减少了64.4%,在妊娠第9天比对照组同期减少了69.9%;对胚胎的大小进行测量时发现,交感神经损毁组在妊娠第7天与对照组同期相比,长径减小了0.51 mm,短径减小了0.56 mm;妊娠第9天时,交感神经损毁组与对照组同期相比,长径减小了0.37 mm,短径减小了0.47 mm,差异显著(P<0.05)。说明交感神经主要影响胚胎的早期发育,对发情周期和排卵没有明显的影响。     

Effect of dietary supplemental ascorbic acid and folic acid on the growth performance,redox status,and immune status of broiler chickens under heat stress

This experiment was conducted to investigate the effects of dietary supplemental L-ascorbic acid (AA) and folic acid (FA) on broiler chickens under heat stress (HS) conditions when supplemented either alone or in combination. For this aim, the effect of these supplements on the broilers’ growth performance, some blood parameters, antioxidant, and immune status were evaluated. Hatchling Cobb-500 broilers (total = 240) were fed either corn and soybean meal-based diet (control group) or basal diet supplemented with 200 mg AA/kg diet, 1.5 mg FA/kg diet, or 200 mg AA plus 1.5 mg FA/kg diet, for 35 days during the summer months (n = 6 replicates/group, 10 birds/replicate). The minimum and maximum average temperatures ranged from 84.5 to 96.2 °F, and the relative humidity ranged from 68.5 to 76.5%. Supplemented vitamins either alone and (or) in combination increased (P < 0.01) broilers’ growth performance, thyroid hormones levels, insulin growth factor1, blood hemoglobin, total protein, albumin, globulin, heat shock protein70, total antioxidant capacity, catalase enzyme activity, superoxide dismutase enzyme activity, antibody titer against Newcastle disease virus, and decreased (P < 0.01) heterophil/lymphocytes. The effects (P < 0.01) of the supplemented vitamins on the analyzed parameters were better when they were added in combination. In conclusion, the combination of AA and FA at 200 and 1.5 mg/kg, respectively, increased the broilers’ antioxidant status with coordinated improvement in the growth performance and health status under HS.

     

热应激对雄鼠生殖器官及精子发生的影响

每天在固定时间用不同梯度温度(42℃,37℃和33℃)处理实验组鼠1 h,热应激前后分别记录小鼠的肛温和体重.在应激的第8 d、13 d分别处死受试鼠后分离睾丸、附睾并分别称量其重量,计算睾丸、附睾与体重指数,将睾丸和附睾组织切片后镜检.结果表明,应激组小鼠的肛温显著升高(P＜0.05);睾丸和附睾内的精子数量、生精细胞上皮层数显著减少,精母细胞数量减少,且排列混乱,细胞的凋亡数量增多;而睾丸、附睾与体重指数无明显变化.     

Oxidative stress and redox regulation on in vitro development of mammalian embryos

Many factors affect development of mammalian preimplantation embryos in vitro. It is well known that in vitro development of bovine embryos is highly affected by culture condition including energy source, growth factors, pH or gas environment. Many efforts have been made towards the suitable environments which can successfully support embryo development in vitro. For a rapid growth and differentiation, embryo requires energy by utilizing ATP, NADPH with oxygen molecules. These energy substrates are produced from the electron transport chain in the mitochondria. In addition to energy production, reactive oxygen species (ROS) are also generated as by-product of such energy production system. ROS production is sensitively controlled by the balance of oxidizing and reducing status and affected by several antioxidant enzymes such as superoxide dismutase (SOD), Catalase, glutathione peroxidase (GPx) or low molecular weight thiols such as glutathione (GSH). Imbalance of oxidation and reduction causes production of excess ROS, which causes the developmental arrest, physical DNA damage, apoptosis induction or lipid peroxidation. Environmental oxygen condition during embryo culture also highly affects embryo development as well as intracellular redox balance. Several studies have revealed that regulation of intra- and extra- cellular reducing environment by reducing excess ROS by using antioxidants, reducing oxygen concentration are effective for improving embryo development. Also, recent studies have demonstrated the difference in gene expression affected by oxidative stress. This review briefly summarizes the effects of ROS and the role of redox balance on preimplantation embryos for improving the efficiency of in vitro production of mammalian embryos.     

Effects of transportation on early embryonic death in mares

Incidence of early embryonic death (EED) and associated changes in serum cortisol, progesterone and plasma ascorbic acid (AA) in transported mares were investigated. Mares were transported for 472 km (9 h) during either d 16 to 22 (T-3 wk, n = 15) or d 32 to 38 (T-5 wk, n = 15) of gestation. Blood samples were drawn from control, nontransported mares (NT-3 wk, NT-5 wk, n = 24) and transported mares pre-trip, midtrip, and at 0, 12, 24, 48 and 72 h post-transport and daily for the next 2 wk. Incidence of EED between transported and nontransported mares was not different (P greater than .05). Serum cortisol in all transported mares increased (P less than .05) relative to pre-trip values at midtrip and 0 h post-transport. Relative to NT mares, serum cortisol was higher (P less than .05) at midtrip in T-3 wk mares and 0 h post-transport in T-5 wk mares. Serum progesterone in all T mares increased (P less than .05) at midtrip relative to pre-trip values and was higher (P less than .05) in T-3 wk mares than in NT-3 wk mares at midtrip and 0 h post-transport. Post-transport decreases (P less than .05) in concentrations of progesterone were observed in mares that aborted. Plasma AA in transported mares increased (P less than .05) at midtrip in T-5 wk mares and decreased (P less than .05) relative to pre-trip values at 24 and 48 h post-transport (T-3 wk and T-5 wk mares, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

热应激对奶牛血液中内毒素含量和抗氧化指标的影响

选用16头健康的中国荷斯坦奶牛,随机分为两个处理（夏季组和冬季组）,每个处理8个重复,每个重复1头牛。当夏季组奶牛牛舍温湿度指数（THI）〉72的时间连续达到15d,冬季组牛舍THI〈72的时间连续达到15d时,颈静脉采血15mL制备血清,检测血清中内毒素、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）的活性,以及丙二醛（MDA）的含量。结果表明：夏季热应激可导致奶牛血清内毒素、MDA含量极显著升高,SOD和GSH-Px活性极显著和显著（P〈0.05）下降。     

醋酸铅对母鼠生殖与胚胎发育影响

将420只体质量为(15.32±2.01)g的雌性昆明系小鼠随机分为5个处理组和1个对照组,每组设7个重复,每个重复10只。各处理组分别腹腔按体质量注射10、15、20、25、30mg/kg的醋酸铅溶液,对照组注射等体积的灭菌生理盐水,每隔2d注射并称重1次,共注射10次,期间记录小鼠体质量及临床表现。当小鼠体质量达到25g以上时,分批对各试验组和对照组进行超排处理,腹腔注射10IU马绒毛膜促性腺激素(PMSG),47h后注射10IU人绒毛膜促性腺激素(hCG),并与公鼠合笼。合笼后87~96h内颈椎脱臼处死小鼠,观察卵巢、子宫形态,并统计胚胎数,同时制作卵巢、子宫石蜡切片,观察其病理组织学变化,研究醋酸铅对雌性小鼠卵巢、子宫组织结构及早期胚胎发育的影响。结果显示:(1)当醋酸铅染毒剂量≥20mg/kg时,可明显抑制小鼠体质量的增长,随着染毒剂量的增加,作用时间的延长,小鼠体质量增加明显趋缓,与对照组相比,差异显著或极显著(P0.05,P0.01);(2)染铅组母鼠早期胚胎发育受到显著影响,主要表现为回收胚胎总数以及受精卵发育到桑椹胚和囊胚的总数均显著低于对照组(P0.05),而各染铅组退化胚、延迟胚数和未受精卵总数显著高于对照组(P0.05);(3)染铅组卵巢中的初级卵泡、次级卵泡、成熟卵泡数量明显低于对照组,而原始卵泡、闭锁卵泡数量明显高于对照组。(4)染铅组小鼠卵巢和子宫形态发生明显畸形,当醋酸铅染毒剂量≥20mg/kg时,与对照组相比,差异显著或极显著(P0.05,P0.01)。且上述变化均呈明显的剂量一时间效应。研究结果表明,当醋酸铅暴露剂量≥20mg/kg时,可对小鼠生长发育具有明显抑制作用,同时使母鼠生殖器官卵巢和子宫的结构造成严重损害,并影响其生殖功能与早期胚胎发育。     

热应激对种公牛精液品质的影响

作者阐述了热应激对种公牛精液品质的影响及使公牛的促黄体素(LH)、睾酮水平降低，精子生成受阻，精液品质严重下降。热应激所致的精液品质下降需经7～9周才能恢复正常。降温可减缓热应激对种公牛繁殖机能的危害。     

光照周期和饲喂水平对蛋鸡卵巢和输卵管形态发育的影响

为研究光照周期和限饲对蛋鸡卵巢和输卵管发育及形态学的影响,选用体质健康的10周龄海兰灰蛋鸡240只,采用3×2双因子设计,分别在短光照周期(8L∶16D),中长光照周期(12L∶12D)和长光照周期(16L∶8D)下采取自由采食(对照)和限饲(自由采食量的80%)处理,共计6个组,分别为短光照对照组(Ⅰ)、短光照限饲组(Ⅱ)、中长光照对照组(Ⅲ)、中长光照限饲组(Ⅳ)、长光照对照组(Ⅴ)和长光照限饲组(Ⅵ),每组4个重复,每个重复10只鸡。结果显示:1光照周期显著影响14周(w)卵巢单位面积内卵泡数量(P0.05)及18 w卵巢卵泡直径(P0.05),短光照周期组卵巢单位面积内卵泡数量显著高于中长光照周期组(P0.05);短光照周期的卵巢卵泡直径显著高于中长光照周期和长光照周期组(P0.05);2饲喂水平显著影响14 w卵巢重及18 w卵巢卵泡直径(P0.05),Ⅲ组卵巢重显著高于Ⅳ组(P0.05),3个对照组18 w卵巢卵泡直径分别显著高于其限饲组(P0.05);3光照周期与饲喂水平的互作对18 w卵巢卵泡直径及18 w卵巢单位面积内卵泡数量影响显著(P0.05);43个对照组输卵管皱褶发育均匀,皱褶长度,厚度明显优于其限饲组。     

Effects of fever and hyperthermia on the embryonic development of rabbits.

The effects of viral induced fever and environmental hyperthermia on embryonic development in pregnant rabbits are described. Embryonic development was not disturbed following fever, but there were anomalies in development following hyperthermia. Possible explanations for the different effects of hyperthermia and fever are discussed.     

热应激对反刍动物营养物质消化、瘤胃发酵、甲烷生成的影响及缓解热应激的措施

热应激是影响动物生产的重要因素.正常的瘤胃功能是反刍动物健康生产的重要保证.了解热应激对瘤胃功能的影响,有利于针对性地采取营养措施缓解热应激造成的对反刍动物的不利影响.文章主要综述热应激对反刍动物营养物质消化、瘤胃发酵、甲烷生成的影响及缓解热应激的措施.     

急性热应激对鸡呼吸系统损伤及肺脏热休克蛋白表达的影响

为探讨热应激对鸡肺脏组织损伤的影响,将60只35日龄SPF鸡随机分为对照组,热应激1、2、3、5、10 h组,每组10只,试验开始后环境温度迅速从25℃升高到35 ℃,观察热应激组鸡临床症状,热应激结束迅速剖杀、取病料,检测血清pH值、乳酸脱氢酶(LDH)、钾离子和钙离子浓度,石蜡切片检测肺脏组织结构,Western ...     

调节胚胎期代谢提高蛋鸡抗热应激能力

应用维生素E、维生素C及普鲁卡因组合的生理调节剂对蛋鸡胚胎期进行调控，试验分为对照组和3个不同剂量组合的试验组，即试验1组（VE＋VC）、试验2组（VE＋普鲁卡因）、试验3组（VE＋VC＋普鲁卡因），研究不同剂量及组合的胚胎调节剂对出壳后母鸡在热应激条件下生产性能、血液指标和卵泡的变化。试验结果显示：试验1组应激前后平均蛋重分别提高7．50％和9．82％（P〈0．01）；热应激期产蛋率提高5．81％（P〈0．05）。试验2组应激前后产蛋率分别提高了7．45％和9．69％（P〈0．01）。试验1、2、3组总产蛋量在应激前后均有提高，尤其试验1组和2组（P〈0．01）。常温期试验1组胰高血糖素和试验3组T4水平分别提高55．52％和10．03％（P〈0．01）；试验1、2、3组热应激期T4水平分别提高28．65％、132．74％和72．79％（P〈0．05）或（P〈0．01）。试验2组热应激期白蛋白水平和常温期葡萄糖水平分别提高27．36％和31．16％（P〈0．05）；试验3组常温期葡萄糖水平提高25．15％（P〈0．05）。试验2组异嗜性粒细胞和H／L的比值下降，单核细胞数上升（P〈0．05）。试验2组卵泡中大白泡和小白泡的数量显著增多（P〈0．05）。以上结果表明，补充适量的Ve、Vc和普鲁卡因能提高蛋鸡抗热应激能力，改善产蛋性能。     

Storage of hatching eggs: The effect on early embryonic development

1. Embryos of eggs incubated for 42 h after storage for 7 or 14 d were retarded by 5.3 and 12.2 h, respectively, compared with those of non‐stored incubated eggs.

2. This was not due entirely to a delay in the initiation of embryonic development; the rate of development during the first 2 d of incubation was significantly lower in eggs stored for 14 d than in non‐stored eggs.

3. There was no correlation between the developmental age of an embryo after any specified incubation time and either the original weight of the egg or the weight loss during storage.

4. The incidence of dead and malformed embryos increased progressively with the duration of storage.     

热应激对动物体内蛋白质周转代谢的内分泌途径的影响

本文讨论了高温条件下机体内分泌激素对蛋白质合成、分解的影响,试图从内分泌角度解释高温对动物体蛋白质沉积的影响机理.     

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