卡麦角林对黄毛鼠睾丸组织结构及四种标志酶活力的影响

为探讨卡麦角林剂量和处理后时间对雄性黄毛鼠睾丸组织结构和相关酶活力的影响,以50μg/kg和100mg/kg卡麦角林连续3d灌胃雄鼠,在处理后第7d和24 d镜检睾丸组织并分析组织中酸性磷酸酶（Acid phosphatase,ACP）、碱性磷酸酶（Alkaline phosphatase,AKP）、乳酸脱氢酶（Lactate dehydrogenase,LDH）、谷胱甘肽过氧化物酶（Glutathione peroxidase,GSH-Px）的活力。结果发现：卡麦角林可使曲细精管内生精细胞、间质细胞和支持细胞受损,脱落解体。100µg/kg卡麦角林可降低ACP酶活力,处理后24 d时恢复;处理后AKP酶与对照无显著差异。处理组LDH酶活力显著增加,但剂量增加导致LDH活力增加幅度下降,且处理后24 d时恢复。100 µg/kg卡麦角林处理后24 d 时,GSH-Px酶活力显著高于对照组,且高于同浓度处理组第7d时的酶活力。处理后相同时间检测的GSH-Px活力高于50µg/kg处理组。结果表明卡麦角林对雄鼠生殖系统有一定的影响,可明显影响睾丸标志酶的活力。     

卡麦角林对雄性黄毛鼠社会行为的影响

不育控制既可直接降低害鼠种群的生育率,又能影响个体的社会行为,引起种群内等级关系和社群结构的变化,进而干扰种群繁殖。为探究不同剂量卡麦角林对雄鼠行为的影响和持效时间,选取健康雄性黄毛鼠使用50mg/kg和100 mg/kg卡麦角林灌胃给药,并于给药后第1 d和第18 d与正常雄鼠遭遇,第4 d和第21 d与正常雌鼠遭遇,比较给药前（卡麦角林灌胃前4 d和前1 d 时分别与正常雄鼠和雌鼠遭遇）和给药后个体行为的差异。结果显示：卡麦角林降低了雄鼠对正常雄鼠的探究、攻击时间,降低雄鼠对正常雌鼠的攻击时间和频次;100 μg/kg卡麦角林降低雄鼠对正常雌鼠的探究频次,且雄鼠自身修饰和休息频次显著减少。这表明卡麦角林可干扰黄毛鼠对同性和异性个体间的社会行为。此外,药物处理后第18 d和第21 d,雄性个体与同性和异性个体的社会行为与处理前无显著差异,表明停药后药物对行为的影响会随着时间的延长逐渐消失。       

黑线仓鼠繁殖输出与基础代谢率的关系

为了解黑线仓鼠繁殖输出与基础代谢率(BMR)的关系,阐明最大持续能量收支(SusMR)的限制水平, 揭示哺乳期能量收支对策,本文测定了哺乳期黑线仓鼠的体重、摄食量、BMR 和身体组成,以及哺乳期的胎仔数、胎仔重和泌乳能量支出(MEO)。结果显示,黑线仓鼠哺乳期体重降低了15.0 ± 0.8% , 摄食量显著增加, 哺乳高峰期平均摄食量为13.9 ± 0.3 g /d, 摄入能为222.1 ± 5.3 kJ/ d, 比哺乳初期增加121% , 比对照组高288% ;哺乳高峰期MEO 为62.4 ± 2.3 kJ/ d, 哺乳末期BMR 为49.7 ± 1.1 kJ/ d; 断乳时平均胎仔数4.7 ± 0.2、窝胎仔重50.5 ±1.6 g; 哺乳末期BMR 比对照组增加48% ,BMR 与消化系统各器官的相关性高于对照组; BMR 与胎仔数、胎仔重、乳腺重量和MEO 显著正相关。结果表明:初次繁殖的黑线仓鼠哺乳期SusMR 限制为4.47 ×BMR, 在自身维持和繁殖输出之间采取了“权衡分配”的原则,通过体重降低以减少BMR 的增加幅度, 从而有利于繁殖输出。     

剃毛和增加胎仔数对KM 小鼠哺乳期能量收支的影响

为探讨最大持续能量收支限制的因素和生理机理,本文测定了增加胎仔数和背部剃毛的KM 小鼠的哺乳
期摄食量和繁殖输出。基础代谢率(BMR)以封闭式流体压力呼吸计测定。结果发现,增加胎仔数对哺乳期体
重、摄食量、热传导率、BMR 和胎仔重的影响不显著;与非剃毛对照组相比,剃毛使哺乳高峰期日平均摄食量
增加了13.8% (P<0.001)、BMR 增加了18.1% (P< 0.01)、热传导增加了30.8% (P< 0.01),但剃毛对体
重、胎仔数和胎仔重的影响不显著;胎仔数与断乳时胎仔重显著正相关,与幼体平均体重显著负相关。BMR 与
母体体重和胎仔重显著正相关。这些结果表明,KM 小鼠哺乳期能量收支受到了限制,剃毛显著增强了KM 小鼠
的散热能力,但未影响繁殖输出;支持“外周限制假说”,不符合“热耗散限制假说”。     

不同剂量米非司酮对雌性小鼠繁殖的影响

为确定米非司酮抑制害鼠繁殖的效力及适宜剂量,每2 周对雌鼠灌服不同剂量的米非司酮1 次,检测给药期间和停药后小鼠繁殖及幼鼠的生长状况。结果发现,给药期间米非司酮抑制小鼠繁殖效果存在一定的量效关系。按体重小于1.25 mg/ kg 剂量的米非司酮对小鼠繁殖无显著抑制作用;2.5 mg/ kg 以上剂量能降低小鼠的产仔率;5 mg / kg 剂量能显著降低产仔率和胎仔数;10 mg / kg 以上剂量能使小鼠完全不育。停药后雌鼠繁殖能力的恢复与之前用药剂量负相关,给药组第一胎平均胎仔数仍显著少于对照组,且第一胎分娩时间也被延迟;至第二胎时平均胎仔数趋于恢复。该结果表明多次给予米非司酮能够有效抑制雌鼠繁殖,停药后仍有一定的持效期,因此具有作为害鼠不育剂的良好潜力。     

不同来源乳铁蛋白对幼鼠肠道发育的影响

目的 探究哺乳期乳铁蛋白（lactoferrin，LF）的缺失及不同来源LF补充后对幼鼠肠道发育的影响。方法 以LF基因敲除型雌鼠作为哺乳母鼠造成幼鼠哺乳期无LF的摄入，且从幼鼠出生第3~21天每日人工饲喂100 mg/kg 牛血清白蛋白（BSA）、牛源乳铁蛋白（bovine Lactoferrin，bLF）及重组人源乳铁蛋白（recombinant human Lactoferrin，rhLF），于幼鼠21日龄取样，测定各组小鼠小肠发育指标。结果 在本实验周期下，哺乳期rhLF的补充显著性增加小鼠回肠绒毛长度/隐窝深度值（P<0.05），且上调回肠Occludin和ZO-1基因的表达（P<0.05），增加小鼠十二指肠、空肠和回肠麦芽糖酶酶活/乳糖酶酶活比值（P<0.05），表明哺乳期rhLF的补充能够增强小鼠肠道消化吸收能力和肠屏障功能；哺乳期bLF的补充显著增加小鼠十二指肠及回肠麦芽糖酶活性/乳糖酶活性比值（P<0.05）。结论 对于哺乳期无LF摄入的乳鼠来说，哺乳期间LF的补充能够增强乳鼠肠道对营养物质的消化吸收能力、促进肠道的发育成熟、增强肠道屏障功能，并且，本实验中rhLF表现出比bLF更加有效的作用。     

妊娠期腹腔注射多氯联苯对大鼠生长发育的影响

将50只同期怀孕的大鼠分为5组,在怀孕第7—18d,每天给两组大鼠腹腔分别注射1和20mg／kg体重2,2’,4,4’-四氯联苯(PCB47);给另两组分别注射0．25和1mg／kg体重3,3’,4,4’-四氯联苯(PCB77);对照组注射0．1mL芝麻油。幼鼠出生时记录每窝产仔数和性比;出生后每隔7d称体重直到第119d;出生后第15天时检查幼鼠的睁眼率。与对照组相比,PCB47和PCB77所有剂量组每窝产仔数和性比无显著差异;PCB47(20g／kg体重组)和PCB77(两个剂量组)雌幼鼠肛门一生殖孔距离显著增加,出生后15d幼鼠的睁眼率显著降低;PCB77(1mg／kg体重组)雄幼鼠从出生后第35至119天体重显著降低。提示PCB77主要影响雄鼠的生长发育。     

广州地区西藏小型猪的繁殖行为学表现

目的对广州地区西藏小型猪的繁殖性能和繁殖行为进行了观察研究。方法以广州地区雌雄西藏小型猪为研究对象,根据其繁殖卡的详细资料进行分类统计。结果雄性西藏小型猪阴茎首次伸出日龄为(39.50±2.63)d,此时体重为(3.26±0.87)kg;其射精日龄为(65.22±3.69)d,体重为(5.34±1.03)kg。雌性西藏小型猪初情日龄为(142±5.3)d,成年母猪发情周期为(20.35±0.72)d,发情持续期(4.2±0.31)d;其妊娠期约为114 d左右。初产雌性西藏小型猪产仔数为(2.30±0.82)头,2月龄断乳存活率为86.5%;而经产雌性西藏小型猪产仔数为(5.70±1.00)头,其2月龄断乳存活率为91.4%。哺乳期雌性西藏小型猪母性强,护仔行为强烈。结论广州地区西藏小型猪生长发育繁殖正常,产仔率和2月龄存活率等繁殖性能指标与原产地一致。     

小鼠基础代谢率与繁殖输出和繁殖期末器官的关系

以封闭式流体压力呼吸计测定KM小鼠(Mus musculus)的基础代谢率(BMR);采用残差分析和Pearson相关分析检验BMR与繁殖输出、内脏器官的相关性。哺乳末期BMR显著高于繁殖前,繁殖前BMR与繁殖输出不相关,但哺乳末期BMR与体重、摄食量、胎仔数和胎仔重、内脏器官和消化道显著正相关;与消化道器官的相关性高于其他内脏器官。研究结果支持"哺乳期较高的BMR有利于消化系统增强消化和吸收能力,以增加能量摄入用于繁殖输出"的假设。     

BALB/c-nu裸小鼠繁殖中杂合仔鼠剔除时间对纯合裸仔鼠生长发育的影响

目的研究屏障设施下裸小鼠繁殖生产时,在不同时间段剔除杂合仔鼠对纯合裸仔鼠的成活率及生长发育情况的影响。方法选取25窝头胎生BALB/c-nu新生裸小鼠按剔除杂合仔鼠的时间不同分成五组,以24h剔除组为对照比较纯合裸仔鼠生长发育及死亡率、离乳率的差异性,统计分析其生长发育过程中的体重增长等。结果剔除组生长发育及死亡率与对照组之间均存在差异性,其中14d剔除组和21d剔除组差异极显著。结论剔除杂合仔鼠的时间对纯合裸仔鼠的成活率及生长发育情况的有很大影响。为了保证SPF级裸鼠生长发育要求,生产繁殖出合格的实验用裸小鼠,剔除全部杂合仔鼠的最佳时间应该在新生仔鼠出生24h内,超过3d则会极大地影响纯合裸小鼠的正常生长发育。     

Effects of oral meso-2,3-dimercaptosuccinic acid (DMSA) administration on late gestation and postnatal development in the mouse

The present study was conducted to evaluate the effects of meso-2,3-dimercaptosuccinic acid (DMSA) on late gestation and postnatal viability and growth in the mouse. DMSA was given po to four groups of pregnant Swiss mice at 0, 200, 400, and 800 mg/kg/day from day 14 of pregnancy until postnatal day 21. At birth, the following data were recorded: length of gestation, number of live, dead, and abnormal pups, sex, and individual pup weights. Each pup was weighed again on day 4, 14, and 21 of lactation. Pinna detachment, incisor eruption and eye opening were also monitored. No treatment-related signs of toxicity were noted in any of the dams during the study. No adverse effects on offspring survival or development were evident in the 200 or 400 mg DMSA/kg/day groups. However, on days 14 and 21 of lactation a significant decrease in pup body weight was observed in the 800 mg/kg/day group. Also, a significant increase in the relative weight of the brain was seen in this group. The "no observable effect level" (NOEL) for health hazards to the developing pup was greater than 400 mg/kg/day. This dose is higher than the amounts of DMSA usually given in the treatment of human heavy metal intoxications.     

Effects of chronic ingestion of caffeine on mammary growth and reproduction in mice

Normal mammary gland growth and reproduction were examined in C3H/HeMei mice given caffeine as drinking water (500 mg/l tap water) after weaning on day 20 of age. Caffeine ingestion had little effects on any of the day of vaginal opening, body growth, pattern of estrous cycles, mammary gland growth and reproduction except for the rearing rate on day 12 of lactation. Five out of 12 mothers given caffeine lost all pups before day 12 and resulted in 51% of the rearing rate on that day, while that of the control was 91%. The rate did not change thereafter in either group. The results indicate that the chronic heavy ingestion of caffeine would induce the high mortality of pups during early stage of lactation.     

Inhibition of lactation in the Beagle bitch with the prolactin inhibitor cabergoline (FCE 21336): Dose response and aspects of long-term safety

Sixteen healthy, lactating Beagle bitches with litters of three to six pups were assigned to four treatment groups for one daily oral treatment of cabergoline in an oily solution (0, 1.25, 2.50 or 5.0 mcg/kg body weight (BW) for 5 d, commencing on Day 8 of lactation. Bitches and all their puppies were weighed daily for 2 d before treatments started, and for 10 d thereafter. Technicians rated daily treatment effects on maternal health, maternal behavior and mammary glands, using a scoring system. Treatments had no effect on maternal health, maternal body weight, and maternal behavior. Treatments with the two higher doses caused a reaction and a regression of the mammary glands in a dose-related fashion, resulting in cessation of lactation with 5 mcg/kg BW. Maternal treatment did not adversely affect the puppies' health, and no puppy was lost during the trial. However, average daily weight gains of puppies declined with increasing levels of cabergoline, causing significant weight losses in the 2.5 and 5 mcg/kg treatment group. This became evident after 2 d of treatment. To save the puppies in the highest dosage group, hand-feeding, and later, crossfostering, had to be used with all litters, starting on Day 3 or 4 of treatment. Weight losses were dose-related with an ED(50) of 1.5 mcg/kg/d and persisted for at least 24 h after treatment had ceased. Since puppies were left with their mothers to provide a continued suckling stimulus, lactation rebounded in all bitches treated with 2.5 mcg/kg, but only in two of four bitches treated with 5 mcg/kg. All bitches returned to estrus at their normal intervals. Fertility and fecundity at the next breeding were undisturbed.     

Malnutrition in utero and lactation: relation between the weight gained by the mothers and the development of their offspring

Physiological weight changes in rat dams and their offspring as sequelae of malnutrition during pregnancy and lactation have been studied. Daily monitoring of the body weight as well as the consumption of food (malnutrition dams 14 g during pregnancy and 20 g during lactation) and drink in control and malnutrition dams was conducted. The number of pregnant dams that completed their pregnant period successfully was registered as well as the number and weight of the pups at birth and their evolution over a period of a month. The percentage of mortality of the pups during that period has been studied. The present results indicate a highly significant decrease in body weight in experimental dams, which determines a retardation in the physiological development of the pups, and yields a higher percentage of mortality in the experimental animals than in controls. It can thus be concluded that malnutrition in utero and during lactation affects the ratio between weight gain for dams and the physical development of their pups.     

Growth and survival of New Zealand sea lions, <Emphasis Type="Italic">Phocarctos hookeri:</Emphasis> birth to 3 months

Offspring birth mass and growth rate represent important life history traits, which influence many vital population and individual characteristics, while offspring survival is a key factor in variation in female reproductive success. For a threatened population of pinnipeds, such as New Zealand sea lions, Phocarctos hookeri, (Grey, 1844, NZ sea lions), understanding individual life history parameters and population dynamics is vital for their management and conservation. This is the first study of the behaviour of females during parturition, pup birth mass and growth, and pre-weaning survival of NZ sea lions, Enderby Island, Auckland Islands during austral summer breeding seasons, 2001/2002 to 2003/2004. Pregnant females arrived ashore 2.1 ± 0.16 days prior to giving birth. After parturition, mothers suckled their pups for 8.6 ± 0.16 days before leaving on their first foraging trip. Male pups were born significantly heavier than female (males 10.6 ± 1.4 kg, females 9.7 ± 0.9 kg). Pups lost on average 48 ± 0.14 g per day mass during the early postpartum period (between birth and mothers first foraging trip). Pup mortality did not vary by pup sex, birth mass, date of birth or any maternal characteristics however it varied significantly between years due to a bacterial infection epidemic (Pup mortality at 60 days: 2001 32%; 2002 21%; 2003 12%). The absolute growth rate per day for pups was 151 g/day over all years. Pup growth rate measured as the slope of linear line fitted to pup mass by age was consistently higher for pups with heavier birth mass, male pups and during the 2002 season. High offspring mortality and slow growth rates coupled with maternal foraging behaviour at their physiological limits may reflect a threatened species which has limited ability for population growth in an environment which is at the extreme of their historical range and impacted upon by fisheries.     

Breeding biology of weddell seals (Leptonychotes weddellii) at Drescher Inlet,riiser larsen ice shelf,Antarctica

Summary The breeding biology of Weddell seals (Leptonychotes weddellii) was studied at Drescher Inlet (Antarctica) during the austral late winter and spring 1986. The whelping season was estimated to last about 40 days, with a peak in pupping at late October. No post natal mortality was observed during the whole study. The attachment between parous females and their pups was strong during the first five weeks after parturition. From the third week on mothers spent more time in the water than the pups. Data on daily peak haul-out time of pups, post natal presence of pups on the ice and distribution of births during the whelping season, indicate that censuses should be carried out between 12.00 hours and 16.00 hours local time and during three weeks after the peak of the pupping season. Pups weaned between 6 and 7 weeks of age. Hormone concentrations (oestradiol-17 and progesterone) indicated that females did not come into oestrus during lactation. Throughout the whole lactation period the mother dominates the relationship with her pup. Growth of the pups was linear during the first 5 weeks post partum, during which period birth weight (x=29.1kg) increased more than 3 1/2 times. Until the 6th week of age the pups gained on average 2.6 kg/day, the respective weight loss in cows was 5.8 kg/day. The latter represents an average loss of nearly 38% of the initial weight at parturition. During the course of lactation, suckling frequency decreased, whereas the length of each bout increased resulting in an approximately constant total suckling duration per week. Of the energy used by females during the first 5 weeks, 52% was consumed by pups. Pups only took milk and the cows did not feed at all during the whole period of observation. Therefore the realized growth in pups, 10 g/min of suckling, was totally derived from energy stored by the cows.     

Thyroxine-induced hyperthyroidism upon the reproductive performance of female rats.

L-Thyroxine (L-T4) was injected into mature rats daily at levels of 0, 3, 6, 12, 24, 48 and 96 mug/100 g body weight through estrous cycling, conception, pregnancy, parturition and 20 days of lactation. Mothers which lactated to 20 days were killed and mammary glands measured for DNA and RNA content. Those which were not able to maintain their pups were killed on the day when all pups died. Estrous cycling and pregnancy were not markedly effected by exogenous L-T4 at levels 3-96 times the normal thyroxine secretion rate in rats. After parturition the mothers on L-T4 above 12 mug did not allow the pups to suckle. As a result the pups died within 2-7 days after birth. Levels of L-T4 from 3 to 12 mug allowed lactation to progress, but survival of pups to day 20 of lactation was significantly lower than in the normal control group. The results of this study indicate that high levels of L-T4 inhibit mammary growth and mild secretion. This, in turn, results in the loss of pups, probably through depletion of prolactin as a result of higher metabolic rate due to hyperthyroidism.     

Effects of cobalt on postnatal development and late gestation in rats upon oral administration

Four groups of pregnant Wistar rats, each of which consisted of 15 animals were administered 0, 12, 14 and 48 mg/kg/day of cobalt (II) chloride from the 14th day of gestation through 21 days of lactation. The offspring were observed for mortality, body weight, body and tail length and general symptomatology after 1, 4 and 21 days of nursing. The number of litters was higher for the control group. The survival ratios were also higher for the control group. Besides, a dose-dependent delay in the growth of the living young could be observed. No significant differences in organ weights in the animals killed 21 days after birth were observed. The blood parameters analysed did not show differences between the treated and control pups. Cobalt produced toxic effects on the mothers, affecting the late gestation as well as the postnatal development of the pups.