用16S rRNA荧光定量PCR技术分析低出生体重儿肠道菌群变化及影响因素

目的监测低出生体重儿肠道细菌分布情况,并分析影响低出生体重儿肠道微生态平衡的因素。方法以低出生体重儿(1 500g≤体重2 500g)为研究对象,采用16SrRNA荧光定量PCR技术检测新生儿出生后第1天、3天、7天粪便中双歧杆菌、乳杆菌、大肠埃希菌和肠球菌4种细菌的含量,比较正常新生儿与低出生体重儿肠道菌群构建的差异;分析不同胎龄、体重、喂养方式、疾病状态等因素对低出生体重儿肠道微生态平衡的影响。结果 (1)低出生体重儿组和健康新生儿组粪便中大肠埃希菌、肠球菌、乳杆菌和双歧杆菌含量与婴儿日龄呈明显正相关关系,且低出生体重儿组婴儿粪便4种细菌含量均明显低于健康对照组(P0.05)。(2)2 000g≤体重2 500g组低出生体重儿大肠埃希菌和肠球菌含量在各日龄明显高于体重2 000g组新生儿(P0.05),双歧杆菌和乳杆菌含量在3日龄和7日龄阶段明显高于体重2 000g组(P0.05),而1日龄阶段差异无统计学意义(P0.05)。(3)母乳喂养组在3日龄和7日龄阶段双歧杆菌和乳杆菌含量明显高于乳制品喂养组(P0.05)。(4)无并发症患儿组在3日龄和7日龄阶段乳杆菌和双歧杆菌含量明显高于有并发症组(P0.05)。结论低出生体重儿肠道菌群构建规律异于正常新生儿,尤其是乳杆菌和双歧杆菌的定植差异更为突出;低出生体重儿的出生体重与肠道乳杆菌和双歧杆菌的含量呈正相关;母乳喂养对低出生体重儿肠道中益生菌的定植有明显的优势;新生儿相关疾病直接影响低出生体重儿肠道微生态的构建,可导致其胃肠道生态系统的异常;16S rRNA荧光定量PCR技术适用于评价婴幼儿肠道微生态状况。     

邻苯二甲酸酯染毒哺乳期母鼠对雄性仔鼠睾丸Leydig细胞形态及功能的影响

目的:观察邻苯二甲酸二乙基己基酯(DEHP)对哺乳期雄性仔鼠睾丸子Leydig细胞(PLC)形态和功能的影响及作用机制。方法:SD孕鼠20只,随机均分为4组(n=5):正常对照组,低剂量组,中剂量组,高剂量组。仔鼠出生第1天起分别以0、10、100、750 mg/(kg·d)DEHP灌胃染毒母鼠,直到仔鼠出生后21 d。用化学发光法检测雄性仔鼠血清睾酮(T)水平;测量体重、睾丸重量、肛生殖器距离(AGD);光镜及电镜下观察睾丸Leydig细胞形态结构;免疫组化方法检测睾丸类固醇激素合成急性调节蛋白(St AR)表达;Real-time PCR法检测睾丸胰岛素样生长因子Ⅰ(IGF-Ⅰ)mRNA的表达。结果:与正常组比较,低剂量组T无明显变化,中、高剂量组血清T水平明显降低(P0.01)。低剂量组睾丸重量增加(P0.05),高剂量组睾丸重量、仔鼠体重明显下降(P0.01);中、高剂量组AGD明显缩短(P0.01)。低剂量组睾丸Leydig细胞明显增生,呈簇状分布;中、高剂量组睾丸Leydig细胞灶区轻度增生,高剂量组部分生精小管生精细胞层次减少、生精细胞凋亡并脱落。电镜观察各给药组Leydig细胞胞浆脂质颗粒减少,线粒体、内质网减少。低剂量组IGF-ⅠmRNA表达增高(P0.05);中、高剂量组睾丸St AR蛋白表达降低(P0.05)。结论:哺乳期染毒DEHP可干扰仔鼠PLC的睾酮合成,St AR蛋白的降低和Leydig细胞的损伤可能是其机制。     

低出生体重儿肠道菌群及肠道屏障功能的研究

目的研究低出生体重儿的肠道菌群分布情况和肠道屏障功能的变化。方法以低出生体重儿(1 500g≤体重2 500g)为研究对象,采用16SrRNA荧光定量PCR技术和JY-DLT肠道屏障功能分析系统检测低出生体重儿出生后第7天粪便中双歧杆菌、乳杆菌、大肠埃希菌、肠球菌4种细菌的含量以及血清中的二胺氧化酶、D-乳酸和细菌内毒素的浓度,比较正常新生儿与低出生体重儿肠道菌群和肠道屏障功能的差异,分析不同喂养方式、并发症对低出生体重儿肠道菌群及肠道屏障功能的影响。结果 (1)低出生体重儿组粪便中大肠埃希菌、肠球菌、乳杆菌、双歧杆菌含量均明显低于健康新生儿组(P0.05),血清中二胺氧化酶、D-乳酸高于健康新生儿组(P0.05),细菌内毒素水平差异无统计学意义(P0.05)。(2)母乳喂养组低出生体重儿粪便中双歧杆菌和乳杆菌含量明显高于乳制品喂养组(P0.05),且血清中二胺氧化酶和和D-乳酸含量低于乳制品喂养组(P0.05),细菌内毒素水平差异无统计学意义(P0.05)。(3)无并发症组低出生体重儿粪便中乳杆菌和双歧杆菌含量明显高于有并发症组(P0.05),其血清中二胺氧化酶、D-乳酸和细菌内毒素水平均低于有并发症的低出生体重儿(P0.05)。结论低出生体重儿的肠道菌群和肠道屏障功能都与正常新生儿存在差异,母乳喂养有助于肠道有益菌的定植和肠道屏障功能的恢复。     

低出生体重儿肠道微生态构建影响因素的 动态监测

目的动态监测低出生体重儿肠道菌群,分析不同体重、不同喂养方式及疾病状态等因素对患儿肠道微生态的影响,为规范临床低出生体重儿宫外营养支持措施及治疗手段提供依据。方法应用16SrRNA荧光定量PCR技术检测正常新生儿和低出生体重儿生后第1、3、7天粪便中大肠埃希菌、肠球菌、乳杆菌及双歧杆菌的含量。结果 (1)在生后7d内,无论正常新生儿还是低出生体重儿,其粪便中大肠埃希菌、肠球菌、乳杆菌和双歧杆菌的含量均随日龄的增加而增加,且生后7d内正常新生儿的粪便中大肠埃希菌、肠球菌、乳杆菌和双歧杆菌的含量均显著高于低出生体重儿(P0.05),正常新生儿生后7d内粪便中各细菌的增长率均高于低出生体重儿。(2)体重2 000~2 500g的低出生体重儿粪便中大肠埃希菌和肠球菌在各日龄中的含量明显高于体重2 000g的新生儿(P0.05);同时其粪便中双歧杆菌和乳杆菌含量在3日龄和7日龄阶段明显高于体重2 000g的新生儿(P0.05)。(3)3日龄和7日龄母乳喂养组的低出生体重儿粪便中双歧杆菌和乳杆菌含量明显高于乳制品喂养组(P0.05);且母乳喂养组新生儿生后7日内粪便中大肠埃希菌、乳杆菌和双歧杆菌含量的增长率均高于乳制品喂养组,尤其是双歧杆菌的增长率(126.49%vs 54.81%)。(4)合并并发症的3日龄和7日龄的低出生体重儿,粪便中乳杆菌和双歧杆菌含量均明显低于无合并症的低出生体重儿(P0.05);且无并发症组的低出生体重儿其粪便中肠球菌、乳杆菌和双歧杆菌的增长率均高于有并发症组的低出生体重儿,大肠埃希菌增长率则低于有并发症组。结论低出生体重儿肠道菌群的定植时间晚且数量少,体重、喂养方式及有无并发症是影响新生儿肠道菌群丰度的重要因素。母乳喂养可促进低出生体重儿肠道中益生菌的定植。疾病因素会导致肠道菌群丰度的降低,使肠道菌群紊乱,其程度可能与病情的严重程度相关。     

秀珍菇粉对H22荷瘤小鼠体内抗肿瘤作用研究

目的本试验旨在研究秀珍菇抗肿瘤作用及其抑瘤机制。方法选用ICR雄性小鼠60只,取10只作为空白组,剩余50只小鼠通过腋部皮下接种H22小鼠腹水构建荷瘤小鼠模型,造模后随机分为模型组、阳性药(CTX)组、秀珍菇低、中、高剂量组,每组10只。模型组小鼠灌服生理盐水,阳性药组小鼠按20 mg/kg体重隔天腹腔注射注射环磷酰胺(CTX)生理盐水溶液,秀珍菇低、中、高剂量组小鼠分别按750、1500、3000 mg/kg体重每天剂量灌服秀珍菇生理盐水混悬液。给药10 d后,测定各组小鼠平均瘤重,肿瘤抑制率;测定免疫器官脏器指数、血清免疫球蛋白和细胞因子含量;测定肝、肾抗氧化指标;观察肿瘤和脾组织HE染色病理切片。结果 (1) CTX及秀珍菇低、中、高剂量组小鼠的平均瘤重均极显著低于模型组(P0. 01),四组小鼠肿瘤抑制率分别为55. 18%,29. 06%、47. 47%和48. 80%。(2)与空白组比较,模型组小鼠脾指数、血清Ig A和TNF-α含量及肝MDA含量显著升高(P0. 05,P0. 01),血清IL-6含量有上升趋势(P 0. 05),而血清IL-2含量、肝CAT和GSH-Px活性及肾SOD、GSH-Px和CAT活性显著降低(P0. 05,P0. 01);同时,CTX组小鼠胸腺指数显著低于空白组(P0. 05)。(3)秀珍菇对荷瘤小鼠免疫和抗氧化功能异常改变具有逆转作用:与模型组比较,秀珍菇各剂量组小鼠血清Ig A和TNF-α含量及高剂量组小鼠IL-6水平显著降低(P 0. 05,P 0. 01),低剂量组小鼠血清IL-2水平显著升高(P 0. 01);秀珍菇处理还显著提高了各剂量组荷瘤小鼠肝CAT活性及肾SOD和CAT活性(P 0. 05,P 0. 01),显著升高中、高剂量组肝GSH-Px活性和低、中剂量组肾GSH-Px活性(P 0. 05,P 0. 01),并显著降低中剂量组的肝MDA含量(P 0. 05)。(4)与CTX组比较,秀珍菇高剂量组小鼠脾指数显著提高(P 0. 05),而血清IL-6水平显著降低(P 0. 05)。(5)肿瘤组织病理切片显示CTX组和秀珍菇各剂量组的肿瘤坏死面积明显增加。结论秀珍菇可抑制H22实体移植瘤生长,其机制与其具有较强的免疫调节和抗氧化作用有关。     

急性铅染毒对小鼠神经系统的危害研究

目的:了解急性铅染毒对小鼠神经系统的影响。方法:将80只ICR小鼠随机分为4组(n=20):低、中、高汞组小鼠分别予以注射醋酸铅溶液1%(2、10、25 mg/kg)染毒,隔日1次,连续3次;对照组予以等量的生理盐水;染毒后对小鼠行为、体重、血浆、脑匀浆丙二醛(MDA)和总超氧化物歧化酶(T-SOD)生理指标进行测定。结果:铅染毒小鼠易激惹、多动,体重明显降低(P<0.05),血浆丙二醛(MDA)、总超氧化物歧化酶(T-SOD)和脑匀浆丙二醛(MDA)明显增高(P<0.01),并与染铅剂量呈正线性相关(P<0.01)。结论:急性铅染毒能提高小鼠脂质过氧化水平,并可代偿性提高机体总超氧化物歧化酶(T-SOD)活性,确定铅染毒对神经系统具有毒性作用。     

灵孢多糖辅助治疗抑郁症的作用及机制

目的：建立大鼠抑郁模型,研究和探讨灵孢多糖注射液辅助治疗抑郁症的作用及机制。方法：将48只SD大鼠随机分为正常组、抑郁组、生理盐水组及灵孢多糖（低剂量、中剂量、高剂量）治疗组各8只。应用慢性应激刺激的方法诱导抑郁组、生理盐水组、灵孢多糖治疗组大鼠抑郁,通过行为学指标评估建模是否成功。建模成功后,在生理盐水组中注射生理盐水;在灵孢多糖治疗组中分别注射低、中、高剂量灵孢多糖注射液,比较各组间的疗效差异。采用免疫组化的方法测定大鼠脑内多巴胺、去甲肾上腺素、5-羟色胺、酪氨酸羟化酶等单胺类神经递质含量的表达情况。结果：成功的建立了大鼠抑郁模型,抑郁组中大鼠各项行为学指标与正常组相比均明显减少,差异有统计学意义（P〈0．05）;灵孢多糖治疗组大鼠脑内的多巴胺、去甲肾上腺素、5一羟色胺、酪氨酸羟化酶与抑郁组、生理盐水组大鼠脑内的含量均明显升高,差异有统计学意义（P〈0．05）。结论：灵孢多糖注射液对改善抑郁症状有良好的疗效,具有辅助治疗抑郁症的作用。     

过量人参皂苷对小鼠脑组织谷氨酸代谢的影响

目的:探讨过量人参皂苷对小鼠脑组织中谷氨酸代谢的影响。方法:常规饲养昆明小鼠,按照最终浓度低(8 mg/kg)、中(40mg/kg)、高(200 mg/kg)剂量连续灌胃人参皂苷24天,记录小鼠体重变化。第25天颈脱臼处死小鼠,取出全脑匀浆后测定谷氨酸水平,谷氨酰胺酶活力。结果:各实验组与对照组相比,体重明显下降;低、中、高实验组谷氨酸水平分别高与对照组13.66%、21.67%、39.83%,其中中剂量组和高剂量组显著高于空白组(P0.05);谷氨酰胺酶活力较对照组分别增高2.06%、2.91%、10.11%,高剂量与空白组差异显著,有统计学意义(P0.05)。结论:高剂量人参皂苷能使神经系统兴奋,可能与增高谷氨酰胺酶活力、从而提高脑组织中谷氨酸含量有关。     

高体重布氏田鼠产仔数较多但繁殖输出及氧化损伤不受影响

体重可影响动物几乎所有的生物学变量。高体重双亲通常产生较大胎仔数。繁殖过程代价很高,可能伴随着氧化损伤。为比较双亲体重对繁殖期能量学特征、繁殖输出和氧化损伤的影响,检测了高体重组(雌性:51. 5 g ± 1. 6 g;雄性:60. 4 g ±2. 5 g)和低体重组(雌性:35. 5 g ± 1. 2 g;雄性:49. 6 g ± 2. 8 g)布氏田鼠繁殖过程中母体的体重和摄食量,分娩时的胎仔数和胎仔总重,及后代断乳时母体的身体成分、激素含量(血清瘦素和催乳素)和氧化损伤(血清丙二醛、蛋白质羰基和肝脏丙二醛含量)。结果显示:(1)高体重组妊娠末期的母体体重增量显著高于低体重组;(2)高体重组母体的出生胎仔数显著高于低体重组,但出生及断乳时的平均胎仔重、胎仔总重和母体繁殖期间的能量摄入无显著差异; (3)血清激素含量、身体成分、身体脂肪重量及氧化损伤指标均无组间差异。结果表明,高体重布氏田鼠可产生较多的出生胎仔数,但母体并不通过摄入更多的能量来保证其繁殖输出,对氧化损伤也没有影响。这些结果对于理解不同体重的动物在繁殖期间的能量策略以及繁殖与生存之间的权衡等生活史理论具有重要意义。     

石菖蒲不同部位对戊四唑点燃大鼠神经肽Y含量的影响

目的:研究石菖蒲不同部位对戊四唑点燃癫痫模型大鼠神经肽Y含量的影响.方法:SD大鼠80只,腹腔注射戊四唑(PTZ)溶液35mg·kg1体重,隔天1次,共14次.点燃成功的大鼠,分8组,每天灌胃1次,分别给予石菖蒲挥发油50mg·kg-1体重、石菖蒲去油水提液高剂量28g·kg-1体重、中剂量14·kg-1体重、低剂量7g·kg-1体重、β-细辛醚100mg·kg-1体重、α-细辛醚70mg·kg-1体重,阳性对照组给予丙戊酸钠(VPA)126mg·kg-1体重治疗,模型组给予同量生理盐水.另设正常组5只,正常喂养,不作任何处理.治疗36天后注射同剂量戊四唑点燃测试药效,断头取脑,分取海马用放免法测定神经肤Y(NPY)含量.结果:与正常组比较,治疗后造模的各组大鼠海马神经肽Y含量升高,石菖蒲去油水提液低剂量组、阳性组有统计学意义(P<0.01),模型组与正常组比较有统计学意义(P<0.05).结论:治疗后造模各组大鼠海马神经肤Y含量升高,起抗癫痫作用.     

Ameliorative effect of L-methionine on Pb-exposed mice

The present investigation was carried out to study the ameliorative effects of l-Met (l-methionine) on Pb-exposed mice by the measurement of the weight gain, the weight of organs, the Hb content, the level of lipid peroxidation (LPO), and the Pb and Fe contents of selected organs and serum. Thirty mice were randomly divided into the healthy control group (A), the Pb control group (B), and the Pb+l-Met-treated group (C). Lead-induced depression of growth and Hb content was reversed when l-Met was added to the daily drinking water. The level of LPO of all the samples from group B was significantly higher than group A (p<0.05); however, in group C, it was lowered, especially that in the brain, kidney, and serum, which were not significantly different than normal (p>0.05). Significant enhancement of Pb content (p<0.05) and significant decrease of Fe content of all the samples in group B (p<0.05) were observed. However, dietary Met significantly lowered Pb concentration of all the samples (p<0.05) compared to that of the liver and kidney, reaching no significance in comparison to group A (p>0.05). The Fe concentration changed little (p>0.05). The result suggests that l-Met has an ameliorative effect on Pb-exposed mice.     

不同剂量当归口服对硫化钠致小鼠斑秃模型的影响

目的:探讨当归口服对硫化钠致小鼠斑秃模型的影响及其可能机制。方法:将50只雄性KM小鼠随机均分为空白对照组、模型组和当归高、中、低剂量组,每组10只。模型组和当归高、中、低剂量组均以8%硫化钠酒精溶液局部外涂建立斑秃模型,当归高、中、低剂量组予以不同剂量当归煎剂灌胃,空白对照组和模型组予以等体积生理盐水灌胃,每天1次,连续7 d。采用酶联免疫吸附(ELISA)和苏木-伊红素(HE)染色法分别检测小鼠血清白细胞介素-10(IL-10)水平和单位视野毛囊数,同时对小鼠背部脱毛区毛发生长情况进行评分。结果:模型组毛发生长评分、单位视野毛囊数及血清IL-10水平均显著低于空白对照组(P0.05)。与模型组比较,高、中、低剂量组毛发生长评分、单位视野毛囊数及血清IL-10水平均显著高于模型组(P0.05)。中剂量组组毛发生长评分明显高于高、低剂量组(P0.05),低剂量组评分与高剂量组毛发生长评分、单位视野毛囊数及血清IL-10水平比较无明显差异(P0.05)。结论:口服当归对硫化钠致斑秃小鼠模型有生发作用,且以中剂量效果最佳,其生发作用可能与提高血清IL-10水平有关。     

Birth Weight,Intrauterine Growth Retardation and Fetal Susceptibility to Porcine Reproductive and Respiratory Syndrome Virus

The severity of porcine reproductive and respiratory syndrome was compared in pregnant gilts originating from high and low birth weight litters. One-hundred and eleven pregnant gilts experimentally infected with porcine reproductive and respiratory syndrome virus on gestation day 85 (±1) were necropsied along with their fetuses 21 days later. Ovulation rates and litter size did not differ between groups, but fetuses from low birth weight gilts were shorter, lighter and demonstrated evidence of asymmetric growth with large brain:organ weight ratios (i.e. brain sparing). The number of intrauterine growth retarded fetuses, defined by brain:organ weight ratios greater than 1 standard deviation from the mean, was significantly greater in low, compared to high, birth weight gilts. Although γδ T cells significantly decreased over time in high compared to low birth weight gilts, viral load in serum and tissues, gilt serum cytokine levels, and litter outcome, including the percent dead fetuses per litter, did not differ by birth weight group. Thus, this study provided no substantive evidence that the severity of porcine reproductive and respiratory syndrome is affected by dam birth weight. However, intrauterine growth retarded fetuses had lower viral loads in both fetal thymus and in endometrium adjacent to the umbilical stump. Crown rump length did not significantly differ between fetuses that survived and those that died at least one week prior to termination. Taken together, this study clearly demonstrates that birth weight is a transgenerational trait in pigs, and provides evidence that larger fetuses are more susceptible to transplacental PRRSv infection.     

Therapeutic influences of almond oil on male rats exposed to a sublethal concentration of lead

Globally, human exposure to heavy metals has risen dramatically. Lead (Pb) is one of the most toxic heavy metals to human and other living organisms. Pb affects certain biochemical and physiological activities of the body. Many scientific investigations have documented the therapeutic and antioxidant properties of natural products which isolated from plant sources. The present study was therefore undertaken to evaluate the therapeutic influence of almond oil against Pb toxicity in male rats. The experimental rats were distributed into four groups. The first group was served as control. The second group was treated with 100 mg/kg body weight of Pb. The third group was subjected to almond oil (800 mg/kg body weight) and Pb. The fourth group was supplemented with almond oil. After six weeks, blood serum specimens were analyzed. In the second group, Pb produced a marked increase of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), total bilirubin, glucose, triglycerides, low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), creatine kinase (CK), lactate dehydrogenase (LDH), creatinine, blood urea nitrogen (BUN), uric acid and malondialdehyde (MDA) levels, while the levels of total protein, albumin, high density lipoprotein cholesterol (HDL-C), glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were significantly decreased. In contrast, the treatment with almond oil notably improved the biochemical changes and showed antioxidative effect. The present study disclosed the therapeutic influence of almond oil on the basis of its antioxidant effect against Pb toxicity. Moreover, these new findings indicated that the constituents of almond oil have a promising significant potential in biomedical and pharmacological studies.     

虎眼万年青多糖降血糖作用的研究

目的:研究虎眼万年青多糖对四氧嘧啶诱导的糖尿病小鼠的降糖作用以及对糖尿病相关特征的影响。方法:采用腹腔注射四氧嘧啶致糖尿病小鼠模型;分成阳性药物组、模型对照组、空白对照组、虎眼万年青多糖高、中、低剂量组,连续给药14d,观察糖尿病小鼠的体重、血糖水平、总胆固醇(TG)和甘油三脂(TC)的变化。结果:经灌胃给药14d后,与空白对照组比较,模型组小鼠体质量呈下降趋势(P0.01),血糖值(P0.01)、总胆固醇TG(P0.01)、甘油三酯TC(P0.01)均明显上升;与模型组比较,虎眼万年青多糖高、中剂量组能有效降低糖尿病小鼠的血糖水平(P0.01),总胆固醇TG(P0.01),甘油三脂TC(P0.01),并且虎眼万年青多糖高剂量组可缓解糖尿病小鼠体重减轻症状(P0.01),而低剂量组作用效果不明显(P0.05)。结论:虎眼万年青多糖能够降低四氧嘧啶致糖尿病小鼠血糖水平,改善血脂代谢紊乱。     

Effects of oral administration of nicotine on organ weight, serum testosterone level and testicular histology in adult male rats

This study investigated the effects of oral administration of nicotine on body and reproductive organ weight, serum testosterone level and testicular histology in adult male rats. Forty male rats divided into five groups and treated for a period of 30 days with 0.5mg/kg (low dose) and 1.0 mg/kg (high dose) body weight of nicotine while the control rats received 0.2 ml/kg normal saline. The fourth and fifth groups were gavaged with 0.5mg/kg and 1.0mg/kg body weight of nicotine but were left untreated for another 30 days. These groups served as the recovery groups.  At the end of each experimental period, the animals were scarified and their reproductive organs were removed and weighed immediately. There was no significant change in the body weight. There was a significant decrease (p <0.05) in the testicular and epididymal weight of rats for both treatments while the decrease in the seminal vesicle weight for both treatment groups was not significant. The prostate weight was not significantly increased in both groups. The recovery groups showed appreciable recovery in their organ weight. Serum level of testosterone of both groups was significantly decreased in a dose dependent manner when compared with those of the control rats. The histological section showed testicular degeneration and disorganization in the cytoarchitecture, as the observed changes were pronounced in the high dose group than the low dose group. However, there were both regeneration of the germinal epithelium and restructuring of the interstitum towards normal in the recovery groups. No lesion was observed in the epididymis of the rats. The results suggest that nicotine has deleterious effect on the male reproductive organ of albino rats ameliorated by nicotine cessation.     

Effect of level of nutrition on onset of puberty and conception rates of zebu heifers

Sixty zebu heifers were divided into three equal groups and reared on isocaloric diets but on different levels of protein. The protein levels were 19.17% (high), 13.37% (medium; NRC recommendations) and 8.3% (low). All animals were examined weekly per rectum for the presence of follicles and corpora lutea and also checked daily for standing heat. The presence of a mature corpus luteum was considered to indicate the attainment of puberty. Body weight and pelvic dimensions were taken at biweekly intervals. Intact bulls were introduced to heifers after they reached puberty and once they reached 200 kg live weight. Pregnancy diagnosis was carried out at 60, 90 and 120 days following introduction of bulls. Mean age at puberty for heifers in the high protein group (570.4 days), medium protein group (640.8 days) and low protein group (704.2 days) differed significantly (P<0.05). body weight at puberty for heifers in the high, medium and low protein groups was 207.1, 187.0 and 161.7 kg, respectively (P<0.05). Pelvic size at puberty was not influenced by the nutritional level. Conception rates of heifers in the three groups were influenced by level of nutrition. Pregnancy rates for the high protein group (58.8%), medium protein group (27.8%), and low protein group (16.7%) by 90-day post-breeding period were significantly different (P<0.05), but body weight at conception between the groups did not differ significantly. The results show that increasing the protein level in the diet is a means of improving the reproductive performance of zebu cattle.     

合欢花对慢性应激大鼠生长和脑单胺类神经递质含量的影响

为探讨合欢花对慢性应激大鼠生长和脑单胺类神经递质的影响,采用15只大鼠,设置了对照组、应激组和合欢花组3组实验。应激组和合欢花组均接受7天的应激刺激,之后合欢花组再灌胃合欢花10天。实验结束后,取3组大鼠的脑组织,用高效液相色谱法测定高香草酸(HVA)、去甲肾上腺素(NE)、多巴胺(DA)和5-羟色胺(5-HT)的含量。结果表明,应激组大鼠日增重显著低于对照组(P=0.011);而合欢花组大鼠的日增重极显著高于应激组(P=0.002)。应激组大鼠海马、纹状体和前额叶中的HVA含量与对照组相比,虽有升高的趋势,但无显著差异;两组间的NE、DA和5-HT也无显著差异。合欢花组大鼠海马中的HVA、DA含量明显高于应激组,而前额叶中的多巴胺和5-羟色胺,以及纹状体中的5-羟色胺均明显低于应激组。这表明合欢花对慢性应激引起的大鼠生长受抑有缓解作用,对其脑内单胺类神经递质有调节作用。     

Lead and Cadmium Synergistically Enhance the Expression of Divalent Metal Transporter 1 Protein in Central Nervous System of Developing Rats

Divalent metal transporter 1 (DMT1) can transport a large range of ions, including toxic lead (Pb) and cadmium (Cd), across membranes. In this study, a total of 24 rats were divided into four groups for intragastrical perfusion treatment: control, Pb alone, Cd alone, and Pb + Cd. Pb and Cd contents in blood were detected, and the mRNA and protein levels of DMT1 were analyzed in the cerebellum, cortex, and hippocampus. Both Pb and Cd levels were elevated in all groups perfused with Pb and/or Cd, except for Pb level in the Cd-alone group (P < 0.05). The mRNA level of DMT1 did not differ among the four groups (P > 0.05). However, the DMT1 protein expression was significantly increased by 0.9-, 1.0-, and 1.1-fold in cerebellum, cortex, and hippocampus of the Pb + Cd group than in controls, respectively. Pb and Cd exposure can synergistically induce DMT1 protein synthesis and has implications for transportation of toxic ions in the developing rat’s brain. Chengwu Gu and Songjian Chen contributed equally to this work, they are joint first authors.     

美洲鳗鲡幼鱼饲料中鱼油的适宜添加水平研究

为研究饲料中鱼油添加水平对美洲鳗鲡(Anguilla rostrata)幼鱼生长性能、消化酶、体成分及肝脏脂肪代谢的影响, 以确定美洲鳗鲡幼鱼饲料中鱼油的适宜添加水平, 选用初始体重(8.34±0.12) g的美洲鳗鲡幼鱼800尾, 随机分成5组, 每组4个重复, 每个重复40尾; 分别投喂添加0(对照组)、3%(FO3组)、6%(FO6组)、9%(FO9组)和12%(FO12组)鱼油的试验饲料, 试验期56d。结果表明, 饲料中添加鱼油显著影响美洲鳗鲡幼鱼生长性能, FO6组美洲鳗鲡幼鱼的增重率、投饵率和饲料效率显著高于其他处理组(P<0.05)。与对照组相比, 鱼油添加组美洲鳗鲡幼鱼肠道脂肪酶活性显著提高(P<0.05), 蛋白酶和淀粉酶活性显著降低(P<0.05); FO6组、FO9组和FO12组全鱼粗脂肪含量显著提高(P<0.05), 全鱼粗蛋白质含量在FO12组显著降低(P<0.05), 全鱼水分和灰分含量无显著变化(P>0.05); FO9组和FO12组脂肪酸合成酶活性显著降低(P<0.05), FO12组脂蛋白酯酶和肝脂酶活性显著升高(P<0.05)。综上, 饲料中添加适宜鱼油水平可以提高美洲鳗鲡幼鱼的生长性能, 调节肠道脂肪酶活性、全鱼粗脂肪含量和肝脏脂肪代谢酶水平或活性; 美洲鳗鲡幼鱼获得最佳增重率和饲料效率时, 饲料中鱼油添加水平推荐为6.43%—6.78%。