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1.
The effect of ethanol exposure on the fatty acid composition of brown and white adipose tissue in three successive rat progenies at the end of an experimental period (24 weeks) was studied. Ethanol-treated rats received a standard rat chow diet and 5, 10 and 15% ethanol in the ad libitum drinking fluid over 3 successive weeks. Then a concentration of 20% ethanol was maintained for 5 additional weeks up to the end of the experimental period. The males and females in the ethanol treated group were mated to obtain the 1st generation of offspring. Then female and male rats from the 1st generation were mated to obtain the 2nd generation. Finally, males and females from the 2nd generation were mated to obtain the 3rd generation of ethanol treated rats. Another group served as control and received only water and a standard rat chow diet. The control group was handled in the same way as the other experimental groups. In the 1st and 2nd generations the percentage of stearic acid (18:0) decreased and palmitoleic (16:1n7) and oleic acid (18:1n9) increased in both adipose tissues of ethanol-treated rats with respect to control. Additionally, n-3 and n-6 series were reduced both in brown and white adipose tissues. In the 3rd generation the fatty acid composition of the white adipose tissue was similar to that of control rats. Thus, no significant difference in essential fatty acids and oleic acid (18:1n9) were found. However, the fatty acid composition of the brown adipose tissue, in the 3rd generation, was similar to that observed in the 1st and 2nd generation. Thus, a decrease in essential fatty acids and an increase in oleic acid (18:1n9) was found. This suggests adaptation to ethanol consumption during successive progenies in white adipose tissue. However, in brown adipose tissue the values indicate a triglyceride storing during the thermogenesis, which is more important to newborns.  相似文献   

2.
Occurrence of hormonal disorders in 32 mature female albino rats fed on a 2 ppm of dieldrin for 3 weeks prompted a study into the effect of the insecticide on hormonal and histopathological changes in rat. FSH levels were significantly decreased in the 1st and 2nd weeks of the experiment, before they returned nearly to normal in the 3rd week. But LH levels, however, were significantly decreased only in the 1st week and slightly increased in the 2nd and 3rd weeks. Histopathological changes revealed severe haemorrhagic spots in the submucosal areas of the uterine wall, in addition to lymphocytic infiltration in the Graafian follicles due to direct effect of dieldrin on the genital tract of the rats.  相似文献   

3.
本试验旨在研究饲料牛磺酸水平对不同生长阶段斜带石斑鱼幼鱼生长性能和体成分的影响。以酪蛋白和明胶为蛋白质源,配制牛磺酸水平分别为0(D1)、0.5%(D2)、1.0%(D3)和1.5%(D4)的试验饲料。将初始体重为(13.85±0.25)g斜带石斑鱼幼鱼随机分为4组,每组4个水族箱(体积为120 L),每箱放养25尾。试验鱼每天投喂饲料2次至表观饱食,养殖周期84d,分别在饲喂的第28、56和84天称重、取样。试验第1~28天为第1个生长阶段,第29~56天为第2个生长阶段,第57~84天为第3个生长阶段。结果表明:在每个生长阶段下,牛磺酸添加组(D2、D3和D4组)试验鱼的增重率、特定生长率、摄食率和饲料效率均显著高于未添加牛磺酸组(D1组)(P0.05),且D3组试验鱼的增重率显著高于其他牛磺酸添加组(第3个生长阶段的D4组除外)(P0.05)。在同一饲料牛磺酸水平下,第1个生长阶段试验鱼的增重率、特定生长率、摄食率和饲料效率均显著高于第2个和第3个生长阶段(P0.05)。在饲喂至第28、56和84天时,各牛磺酸添加组试验鱼的肝体比和脏体比均显著低于未添加牛磺酸组(P0.05),肥满度则与未添加牛磺酸组无显著差异(P0.05)。在同一饲料牛磺酸水平下,饲喂至第56和84天时的肝体比和脏体比均显著低于饲喂至第28天时(P0.05)。饲喂至第84天时,各牛磺酸添加组鱼体的粗蛋白质含量显著高于而粗脂肪含量显著低于未添加牛磺酸组(P0.05)。上述结果表明,饲料中维持一定水平的牛磺酸有利于斜带石斑鱼幼鱼的生长,饲料牛磺酸不足或过多均不利于其生长。饲料中添加牛磺酸降低斜带石斑鱼幼鱼体脂沉积而增加体蛋白质沉积。以增重率为评价指标,通过回归分析得到3个生长阶段斜带石斑鱼幼鱼饲料的适宜牛磺酸水平分别为1.20%(第1个生长阶段)、1.08%(第2个生长阶段)、1.00%(第3个生长阶段)。斜带石斑鱼幼鱼对牛磺酸的需要量随鱼龄的增长而下降。  相似文献   

4.
Brain stem auditory-evoked response in the nonanesthetized horse and pony   总被引:3,自引:0,他引:3  
The brain stem auditory-evoked response (BAER) was measured in 10 horses and 7 ponies under conditions suitable for clinical diagnostic testing. Latencies of 5 vertex-positive peaks and interpeak latency and amplitude ratio on the 1st and 4th peaks were determined. Data from horses and ponies were analyzed separately and were compared. The stimulus was a click (n = 3,000) ranging from 10- to 90-dB hearing level (HL). Neither horses nor ponies responded with a BAER at 10 dB nor did they give reliable responses at less than 50 dB. The 2nd of the BAER waves appeared in the record at lower stimulus intensities than did the 1st wave for the horse and pony. Horses and ponies had a decreasing latency for all waves, as a result of increasing stimulus intensity. Latencies were shorter for the ponies than for the horses at all stimulus intensities for the 1st, 2nd, 3rd, and 4th waves, but not the 5th wave. At 60-dB HL, the mean latencies for the 1st through 5th wave, respectively, for the horse were 1.73, 3.08, 3.93, 4.98, and 6.00 ms and for the pony 1.48, 2.73, 3.50, 4.56, and 6.58 ms. Interpeak latencies, 1st to 4th wave, averaged 3.22 ms (horse) and 3.11 ms (pony) for all stimulus intensities from 50- to 90-dB HL and had a tendency to decrease slightly as stimulus intensity increased. Amplitude ratios (4th wave/1st wave) were less than 1 for all stimulus intensities in the horse. In the pony, the ratio was less than 1 at greater than or equal to 70-dB HL and greater than 1 at less than or equal to 60-dB HL.  相似文献   

5.
Acute toxicosis developed in a group (n = 35) of fattening hogs and replacement gilts that had excessive vitamin D3 inadvertently added to their feed. All of the pigs were lethargic, and emesis was evident in about half of the pigs 1 to 2 days after they consumed the feed. On the 2nd day, 3 of the pigs died. The remaining pigs were given a different ration. Five additional pigs died during the next 2 weeks. Clinical toxicosis also was observed in 1 of 2 feeder pigs fed the suspect feed in the laboratory and in 2 of 2 pigs fed the suspect feed by the company that had mixed the feed. Gross necropsy findings consistently observed were hemorrhagic gastritis and diffuse interstitial pneumonia. Myocardial degeneration and nephrosis were seen in, respectively, 1 of 6 and 4 of 6 pigs necropsied. Histologically, necrosis and mineralization of variable severity were observed in the fundic gastric mucosa, lungs, kidneys, bone, heart, and small blood vessels of the lungs and heart. Less necrosis and more mineralization were observed in pigs that survived longer than 6 days. The 2 pigs fed the suspect feed in the laboratory had increased concentrations of serum calcium from the 3rd to the 9th days or the 1st to the 3rd days, after feeding the suspect feed. Serum phosphorus concentrations were increased from the 1st until the 2nd or 3rd day, and serum magnesium concentrations were increased from the 1st or 2nd to the 3rd day after feeding the suspect feed.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

6.
五脉山黧豆是长根茎型豆科牧草,是典型的无性系植物.在松嫩平原生长季后期,五脉山黧豆无性系种群生物量59.6%分配于分株,40.4%分配于根茎.经过对样本的观察,创建了按实际生活年限划分豆科植物根茎年龄的方法.五脉山黧豆的根茎最多可生活3个年度,但至生长季后期3龄级根茎存活量甚少,并已经失去了繁殖力.当年形成的1龄级根茎大多是从2龄级根茎上产生.2龄级根茎几乎没有死亡.根茎长度的年龄结构表现为1龄级与2龄级大体相同,3龄级陡度减少.根茎生物量的1龄级比率比根茎长度的有所增加,2龄和3龄级则有不同程度的减少.五脉山黧豆无性系种群采用了优先向1龄级根茎输送与贮藏营养物质的生存与发展策略.在水淹后恢复演替群落具有地被植物种间竞争的条件下,五脉山黧豆仍可以通过指数函数迅速地增加着无性系的子代数量,同时也迅速地扩展着无性系的生态位空间.  相似文献   

7.
Thenium closylate-piperazine phosphate combination tablets, tablets containing either thenium or piperazine, and control tablets (excipients only) were administered in 2 doses 5 to 7.5 hours apart to weaned pups and young dogs, in critical controlled trials to test efficacy against naturally acquired infections of Toxocara canis. In the 1st trial, the combination tablets produced a mean clearance of 94% from 18 pups. Tablets containing thenium alone showed a mean clearance of 9% from 25 pups, and tablets containing piperazine alone caused a mean clearance of 56% from 16 pups. Clearances, corrected for spontaneous worm losses observed in pups treated with the control tablets, were 90% (combination), 5% (thenium alone), and 52% (piperazine alone). In the 2nd and 3rd trials, efficacy of the combination tablet in 15 pups was 78% when corrected for worm losses in pups which had received placebo (excipient) tablets. Each component in the combination tablet contributed its full single-entity efficacy and, if in combination, synergistic effect between the components.  相似文献   

8.
乌苏里貉生长期颗粒配合饲料择优试验   总被引:4,自引:0,他引:4  
作者采用单因子随机分组设计方法对育成期乌苏里貉颗粒配合饲料进行了配方筛选择优试验。结果表明,3个试验组貉其体重、体长的增长均较快,组间无显著差异(P>005);第3组貉对日粮总能、粗蛋白、脂肪的消化率高于1组、2组和对照组,屠宰取皮结果,亦以第3组最好,饲料消耗成本对照组最高,综合比较,本试验以第3组日粮配方较佳。  相似文献   

9.
试验旨在建立猪圆环病毒2型(PCV2)诱导的小鼠体内免疫细胞氧化胁迫模型。筛选PCV2感染剂量及感染时间,采用腹腔注射、滴鼻和灌胃3种途径联合方式于第1、2、3 天或第1、3、5、7天给予昆明系小鼠感染PCV2病毒原液或10-1 PCV2病毒液,分别于感染后7、14、21 d剖杀小鼠,测定活性氧(ROS)、总谷胱甘肽(T-GSH)、还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)水平及黄嘌呤氧化酶(XOD)、髓过氧化物酶(MPO)、诱导型一氧化氮合酶(iNOS)活性,探讨PCV2感染时间与活性氧水平变化的关系,建立免疫细胞氧化胁迫动物模型。结果显示,第1、2、3天每天经3种途径联合感染PCV2病毒原液,1 mL/只,为后续试验感染最佳方案。PCV2感染小鼠3个时间点细胞内ROS水平较空白对照组均极显著升高(P < 0.01),感染后7、14 d GSH水平显著降低(P < 0.05);感染后7 d GSSG水平极显著高于空白对照组(P < 0.01);感染后7 d T-GSH水平显著低于空白对照组(P < 0.05),感染后14 d T-GSH水平极显著低于空白对照组(P < 0.01)。感染后7 d脾脏XOD、MPO、iNOS活性与空白对照组相比均存在显著差异(P < 0.05)。结果表明,PCV2成功感染小鼠,试验感染方案为第1、2、3 天每天经3种途径联合感染PCV2病毒原液,1 mL/只,且用PCV2病毒原液感染7 d是建立小鼠体内免疫细胞氧化胁迫模型的最佳条件。  相似文献   

10.
The aim of this experiment was to establish the oxidative stress model of immune cells in mice induced by PCV2. Optimal infection titer and time of PCV2 were selected. On the 1st,2nd and 3rd day or 1st, 3rd,5th and 7th day,Kunming mice were treated with 100 PCV2 or 10-1 PCV2 by 3 ways (intraperitoneal injection, intranasal administration and intragastrical administration). 7, 14, 21 d post administration, we killed the mice. Reactive oxygen species (ROS),total glutathione (T-GSH),reduced glutathione (GSH),oxidized glutathione (GSSG) levels and xanthine oxidase (XOD), myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) activity were determined to investigate the relationship between the infection time point and the change of ROS level after PCV2 infection. Thus to establish mice immune cells oxidative stress model. The results showed that infection with 100 PCV2 virus in 3 ways every day both at day 1, 2, 3 and 1 mL per mouse was the best program for the follow-up experiment. The intracellular level of ROS of mice infected with PCV2 was extremely significantly increased both at 7, 14 and 21 d (P < 0.01);7 and 14 d post infection, GSH level of PCV2 infected mice had significant difference compared with that of control group (P < 0.05). 7 d after infection, GSSG level was extremely significantly higher than that of control group (P < 0.01); 7 d after infection, T-GSH level was significantly lower than that of control group (P < 0.05), T-GSH was extremely significantly lower than that of control group at 14 d post infection (P < 0.01). XOD, MPO and iNOS activity between PCV2 infection group and blank control group were significantly different at 7 d post infection (P < 0.05). It suggested that PCV2 successfully infected mice, experimental infection programme was Kunming mice were treated with 100 PCV2 by three ways (intraperitoneal injection, intranasal administration and intragastrical administration) both at the 1st,2nd and 3rd day of the experiment.The best condition to establish the oxidative stress model of immune cells in mice was using 100 PCV2 to infect for 7 days.  相似文献   

11.
Studies were conducted into the effects on pituitary gonadotrophic hormones in ovariectomized rats of butorphanol, a synthetic morphine derivative which was claimed to be a potent analgesic with few side-effects, in comparison to effects of the naturally occurring alkaloid morphine. For this purpose, 3 groups of ovariectomized rats were used. Rats of the 1st group were injected butorphanol at 2 dose levels (1 or 2 mg/kg body weight [b.w.]. Those of the 2nd group were injected morphine sulphate (10 or 20 mg/kg b.w.). The 3rd group was injected saline and served as control. Blood samples were collected by orbital sinus punctures, just before treatment and 1 hour post injection. Luteinizing hormone (LH) and follicle-stimulation hormone levels were determined in the sera of rats by radio-immuno-assay. The results revealed that morphine, at the 2 dose levels used, produced more than 90% decrease in serum LH concentration, whereas butorphanol produced more than 70% decrease in serum LH levels. Both morphine and butorphanol, at the 2 doses used, produced more than 76% decrease in serum follicle stimulating hormone concentration. It is concluded that butorphanol, the morphinic derivative, has a depressive effect on the synthesis and/or release of gonadotrophic hormones. This inhibitory effect, however, was nearly as potent as that produced by morphine sulphate.  相似文献   

12.
Studies were conducted during the summer of 2 successive years (1971 and 1972) to determine the effects of gastrointestinal nematode parasitism on performance failure of stocker beef steers grazed at high stocking rates on Coastal bermudagrass pastures. During each of the 2 years, 3 groups of steers were rotated at 7- to 10-day intervals on sets of three 1.63-ha pastures from mid-May to late October. (Each group was maintained on a given set of pastures.) In the 1971 program, from mid-May to early August (phase 1) each group consisted of 48 steers for a stocking rate of 29.6 steers/ha. From early August to late October (phase 2) the number of steers per group was reduced to 36 (stocking rate of 22.2 steers/ha) to improve the plane of nutrition. In the 1972 program, 2 groups were stocked at 48 steers per group (29.6 steers/ha) and a 3rd group was temporarily stocked with 58 steers (10 additional steers) to provide 2 animals each month for necropsy evaluation of worm burdens. With exception of the monthly removal of 2 steers from the 3rd group, the stocking rate in 1972 remained intact for the entire grazing season. In 1971, the 3 groups (groups 1, 2, and 3) were treated with thiabendazole (2 doses, 16 days between doses) before grazing. Parasite burdens and levels of pasture contamination were low initially and body weight gains were good during the 1st 3 months of grazing (phase 1). In the 2nd half (phase 2) of the grazing program, 1 group of steers given free-choice supplemental feed (1% of body weight/steer each day) and treated with anthelmintic (thiabendazole; 2 doses, 18 days between doses, during August) and another group, given supplemental feed only, had significantly better weight gains than did the 3rd group, not given supplemental feed nor treated with anthelmintic. There was no weight gain advantage derived from the reduced stocking rate in phase 2. Tracer calves, which were allowed to graze on pastures, developed an increased level of infection after August. Fecal egg counts in the principal steers and recovery of infective larvae from pasture paralleled the infection level in tracer calves. Necropsy evaluation of steers from groups 1, 2, and 3 at the end of the 1971 program indicated a similarity in total worm counts, but in the group not given supplemental feed nor treated with anthelmintic there was more generalized inflammation and a greater number of lesions in the abomasum (Ostertagia) and the caudal portion of the intestine (Oesophagostomum). Steers in the 3rd group also were in poorer condition. Initial worm burdens in the 3 steer groups (groups 4, 5, and 6) were low at the start of the 1972 program. One group was given freechoice supplemental feed (0.5% of body weight/steer each day) and treated with anthelmintics (thiabendazole in the 1st dose, levamisole in the 2nd dose, 12 days between doses, in May and August) and another group was given supplemental feed throughout the summer; the 3rd group was treated with anthelmintics (in May and August)...  相似文献   

13.
This study was performed to identify, recording from single fibers of the ethmoidal nerve, nasal receptors which respond to changes in the upper airway pressure during nasal occlusion. In 15 anaesthetized rats breathing through the nose, three consecutive nasal occlusions were performed while recording the afferent activity of ethmoidal nerve fibers, the EMG activity of an external intercostal muscle, temperature in the nose and upper airway pressure. Twenty-two afferent fibers were activated during the three inspiratory efforts with occlusions applied at end-expiration, when the upper airway was subjected to negative pressure (-1.93, -2.16 and -2.22 kPa at the 1st, 2nd and 3rd effort, respectively). The number of impulses was 24, 22 and 20 (n = 22) at the 1st, 2nd and 3rd effort, respectively. The pressure threshold were measured as -0.73, -0.87 and -0.96 kPa (n = 22) in each effort. Three fibers were also stimulated by positive pressure during occlusions performed at end-inspiration. In 5 rats breathing through a tracheostomy, maintained negative (-0.1-3.7 kPa) and positive (0.8-3.0 kPa) pressures were applied to the isolated upper airway. All the 12 fibers tested were activated by the maintained negative pressure, whereas three of them were also activated by the maintained positive pressure. However, none of fibers tested were stimulated by tracheal occlusions. These results indicate that the ethmoidal branch of the trigeminal nerve contains fibers connected to nasal 'pressure' receptors, mostly 'negative pressure' receptors, that may play a role in the maintenance of upper airway patency.  相似文献   

14.
紫花苜蓿不同茬次及年际间生产性能的动态规律   总被引:1,自引:0,他引:1  
在海河平原区,先后选取22个、14个苜蓿(Medicago Stiva)品种,雨养条件下通过7年和4年的试验结果表明:不同茬次干草产量表现为逐渐降低的趋势,每年刈割4次:第1茬 > 第2、3茬 > 第4茬;刈割5次:第1茬 > 第2茬 > 第4茬 > 第3茬 > 第5茬;前2茬苜蓿年平均干草产量均占全年总产量的52%以上,第3茬干草占全年总产量的25%以下;随茬次的增加,株高总体上表现为逐渐下降的趋势;第2茬草的叶茎比极显著高于第3、4茬(P<0.01),第4茬草的叶茎比最低;粗蛋白含量为第2、3茬>第1、4茬,并且差异极显著(P<0.01)。苜蓿在海河平原区存在明显的“夏眠”现象,造成了光、温、水资源的浪费。7年连续测定结果表明,在海河平原区紫花苜蓿适宜的利用年限为4~5年。  相似文献   

15.
克隆了家蚕苏氨酸脱氢酶基因(Bmtdh),其cDNA长1 310 bp(No.ABA43639.1),包括227 bp 5′-UTR和1 026 bp的完整开放读码框(ORF)。Bmtdh在家蚕基因组上以单拷贝形式存在,编码342个氨基酸,其Ile29-Val322区域是一个完整的表面异构酶功能域。表达谱分析与EST数据的分析表明,Bmtdh在丝腺和卵巢中的转录水平高于其它组织,并且Bmtdh在家蚕4龄眠期、5龄早期的转录水平也很高,而在卵期(G2胚胎)和1龄早期没有检测到其转录表达,表明Bmtdh基因可能参与了蚕丝蛋白的合成过程。  相似文献   

16.
为培育高产苜蓿(Medicago sativa L.)新品种,以110个苜蓿高产单株的半同胞后代为材料,研究其第1茬、第2茬、第3茬、第4茬及全年产草量一般配合力,并在此基础上进行聚类分析。结果表明:产草量一般配合力较高的植株共22株,一般配合力中等的植株共48株,一般配合力较低的植株共40株;淘汰40株产量一般配合力较低的单株,收到70株产量一般配合力较高的单株相互杂交的种子,完成了一次轮回选择。苜蓿第1茬、第2茬、第3茬、第4茬产草量广义遗传力分别为H2=34.95%,H2=50.42%,H2=29.52%,H2=1.9%;苜蓿全年产草量的广义遗传力为H2=25.58%。  相似文献   

17.
1. Thirty adult female pigeons (Columba livia domestica) were randomly divided into 3 equal groups; the 1st and 2nd groups were immunised with bovine serum albumin (BSA) at 0 and 20 d, the 2nd group also received 1 g L-carnitine per litre of drinking water from -5 to 25 d post-immunisation (dpi) and the 3rd group, a control group, received neither treatment. 2. Body weights and serum samples were taken at 0, 5, 10, 15, 20, 25, 30 and 35 dpi. 3. Both BSA-specific IgG and IgM responses were enhanced by about 10% by L-carnitine supplementation. 4. L-carnitine supplemented pigeons showed a higher water consumption. Body weight loss during the onset of the immune response showed a slight tendency to be counteracted by L-carnitine supplementation. 5. The impact of L-carnitine on resistance and resilience to an immunological challenge is discussed.  相似文献   

18.
The effect of short-term nutritional supplementation on hormonal and ovarian dynamics was studied in goats. Cycling Shiba goats were divided randomly into maintenance (group M, n=4) and high-energy (group H, n=4) groups. After the detection of the ovulation (Day 0, 1(st) ovulation), group H received a high-energy diet providing 2.5 times of the maintenance energy requirement for 7 days from Day 7 to Day 13 and were administered 2 mg of prostaglandin F(2alpha) (PGF(2alpha)) on Day 10 to induce luteal regression followed by the follicular phase. Follicular and luteal dynamics were monitored using ultrasonography daily or every other day, and blood samples were collected daily from Day 0 to the third ovulation (3(rd) ovulation) following the second ovulation (2(nd) ovulation) induced by PGF(2alpha) administration. Blood samples were also collected at 10-min intervals for 6 h on Day 9 and Day 11 for analysis of pulsatile LH secretion. The mean concentrations of glucose and insulin were significantly (P<0.05) higher in group H than in group M on Days 8, 9, 12, 13 and Days 8, 9 and 10, respectively. For both the 2(nd) and 3(rd) ovulations, no significant difference was detected in ovulation rate between groups M and H. On the other hand, the interpeak interval for wave-like patterns of FSH in group H was significantly (P<0.05) shorter than in group M during the period between the 1(st) and 2(nd) ovulations (4.3 +/- 0.3 vs. 6.5 +/- 1.5 days). The mean LH pulse frequency in group H was significantly (P<0.05) greater than in group M on Day 11 (4.5 +/- 0.6 vs. 3.3 +/- 0.5 pulses/6 h). The present study clearly demonstrated that short-term (7 days) nutritional supplementation promoted pulsatile LH and wave-like FSH secretions in cycling goats. However, no significant increase in ovarian performance was found under such endocrine and metabolic conditions.  相似文献   

19.
Survival of Newcastle disease virus (NDV) and Salmonella enteritidis serovar typhimurium (introduced as infected carcasses) in Lactobacillus-fermented edible waste material was studied to determine the ability of the fermentation to activate disease agents in carcasses. Two trials were conducted. In the 1st trial, the fermented wastes contained 20% infected carcasses (protein) consisting of equal numbers of chicken (NDV) and rat (Salmonella) carcasses, and the 2nd trial contained 40% carcasses (protein). Mixtures were incubated at 20 C, 30 C, and 40 C for 216 hours. Samples were obtained daily for quantitative virus and bacterial isolation. Temperature, pH, and redox potential were monitored. In both trials, pH and redox potential changes occurred between 24 and 48 hours depending on the incubation temperature. In both trials, NDV survived 4 days at 20 C, 2 days at 30 C, and 1 day at 40 C. Salmonella enteritidis serovar typhimurium survived 5 days at 20 C, 1 day at 30 C, and was not isolated from the 40 C samples after 24 hours in both trials.  相似文献   

20.
Prenatal stress has been seen as a reason for reproductive failures in pig offspring mostly originated or mediated by changed maternal functions. Experiments were conducted in pregnant gilts (n=32) to characterize effects of elevated maternal glucocorticoids on the secretion of reproductive hormones (LH, progesterone) during the 1st (EXP 1), 2nd (EXP 2) and 3rd (EXP 3) trimester of pregnancy (TP). Transiently elevated cortisol release was repeatedly achieved by application of 100 IU adenocorticotropic hormone (ACTH) (Synacthen Depot) six times every second day beginning either on day 28 (EXP 1), day 49 (EXP 2) or day 75 of pregnancy (EXP 3). Glucocorticoid concentrations were examined in umbilical blood vessels of fetuses which mothers were subjected to ACTH at 2nd and 3rd TP (EXP 4). Furthermore, the pituitary function of newborn piglets of EXP 2 was checked by a LH-RH challenge test. In sows, LH concentrations were at low basal level (0.1-0.2 ng/ml) but with pulsatory release pattern during each TP. The number of LH pulses/6 h (LSM +/- SE) of saline treated Controls increased with ongoing pregnancy and decreased to the 3rd TP (1.3 +/- 0.2 in EXP 1 vs. 2.0 +/- 0.1 in EXP 2 vs. 1.4 +/- 0.1 in EXP 3, p<0.05). After ACTH treatment the number of LH pulses left unchanged in Experiments 1 and 2 (1.3 +/- 0.2 and 1.5 +/- 0.1) and decreased in EXP 3 (0.8 +/- 0.2, p<0.05). Differences (p<0.05) were obtained comparing the LH pulse number of ACTH and saline treated sows at the 2nd and 3rd TP. Moreover, areas under the curve (AUC) of each LH pulse and of LH over baseline were significantly reduced by treatment. Levels of progesterone increased (p<0.05) for 150 to 170 min after each ACTH application both in EXP 1 and EXP 2, but not in EXP 3. The mean progesterone concentration was different between trimesters, and ACTH and Controls (1st TP: 30.0 +/- 0.9 and 24.4 +/- 0.7 ng/ml; 2nd TP: 35.5 +/- 0.9 and 29.1 +/- 1.0 ng/ml; 3rd TP: 13.6 +/- 0.2 and 13.1 +/- 0.1 ng/ml; p<0.05). In fetuses (n=87) recovered 3 h after ACTH or saline (EXP 4), the plasma cortisol concentrations were significantly increased in umbilical vein (93.7 +/- 5.5 vs. 47.0 +/- 5.3 nmol/l) and artery (95.7 +/- 5.4 vs. 66.4 +/- 5.4 nmol/l), and in periphery (46.8 +/- 5.3 vs. 27.1 +/- 5.3 nmol/l) compared to controls. Plasma ACTH concentrations, however, did not differ in fetuses of both treatment groups. Postnatal LH-RH challenge tests (1st and 28th day post partum) induced LH surges in female piglets (n=67) both of ACTH and saline treated sows, but did not differ between groups (1st day: 7.2 +/- 0.8 vs. 8.1 +/- 0.7 ng/ml; 28th day: 10.5 +/- 1.7 vs. 13.6 +/- 2.2 ng/ml). However, basal LH of piglets whose mothers were submitted to ACTH during 2nd TP was lower on 1st day (1.7 +/- 0.2 vs. 2.3 +/- 0.2 ng/ml, p<0.05) but not on 28th day (1.0 +/- 0.2 vs. 1.1 +/- 0.2 ng/ml). However in both groups, the basal LH was always higher on 1st as on 28th day (p<0.05). Thus, chronic intermittent ACTH administration is able to influence the release pattern of maternal reproductive hormones. However, these findings demonstrate that these effects are dependent on the stage of pregnancy. Furthermore, it was shown that maternal cortisol can cross the placenta during gestation and thus may affect maternal-fetal interactions and, as a result, reproductive function of offspring.  相似文献   

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