Digestibility of macronutrients and nitrogen balance in pregnant rabbits

Primiparous New Zealand White does have been used to establish the weekly differences of several apparent digestibility coefficients (CDA) and the nitrogen balance, between pregnant and non-pregnant does, as well as the evolution of the same parameters along the state of gestation. The intake was 180 g/animal and day at the most. The results show that protein followed by dry matter CDAs were the most negatively affected in pregnant does with regard to the non-pregnant ones and throughout the gestation. For the other CDAs, the differences were only significant in the fourth week between pregnant and non-pregnant does, and also with regard to the remaining weeks of gestation. In this way, the organic matter and carbohydrate CDAs were lower whereas the fat one became higher. In relation to nitrogen balance, it was meaningfully greater in the third week of pregnancy with respect to the control animals. Also, a gradual increase may be observed throughout the gestation state, being especially important in the third and fourth week.     

Discriminant analyses for pregnancy-related changes in hematological and serum biochemical values in cynomolgus monkeys (Macaca fascicularis)

Hematological and serum biochemical data obtained from 45 non-pregnant and 142 pregnant cynomolgus monkeys (Macaca fascicularis) were analyzed by discriminant analyses. All animals used had been reared under uniform environmental conditions at Tsukuba Primate Center for Medical Science, N. I. H., Japan. The examination items were as follows: red blood cell count(RBC), hematocrit value(Ht), hemoglobin concentration(Hb), mean corpuscular volume(MCV), white blood cell count(WBC), total protein (TP), albumin (ALB), glucose (GLU), total cholesterol (TCHO), free cholesterol (FCHO), triglyceride (TG), and albumin-globulin ratio (A/G). The pregnant animals were divided into four groups according to their gestation ages (Group I: 1-40 days; II: 41-80 days; III: 81-120 days; and IV: more than 121 days). During pregnancy period (Groups II, III and IV), significant decrease of TP, ALB, TCHO, FCHO and TG was observed. RBC, Ht and Hb decreased in the last of the four periods of pregnancy (Group IV). Discrimination was possible between each of these four pregnant groups and the non-pregnant group on the basis of the Mahalanobis' generalized distance. To clarify the relationship among groups, canonical discriminant analysis (discriminant analysis with reduction of dimensionality) was carried out. As a result, the non-pregnant group and the pregnant I group could be clearly discriminated from the other pregnant groups (II, III, and IV) by the first canonical variate. Judging from the relative eigenvector value of each variable for the first canonical variate, the effective discriminant variables were RBC, Ht, Hb, MCV, TP and A/G.(ABSTRACT TRUNCATED AT 250 WORDS)     

Urinary selenium and iodine during pregnancy and lactation

The New Zealand environment is low in selenium and iodine, and is therefore ideally suited for the study of these anionic trace elements. The aim of this study was to determine urinary excretion of selenium and iodine during pregnancy and postpartum as part of an investigation of the influence of pregnancy and lactation on selenium metabolism in women of low selenium status. In a double-blind placebo-controlled study, 35 women in the earliest stages of pregnancy and 17 non-pregnant women were recruited in Dunedin, New Zealand. Eighteen pregnant women received 50 μg selenium as L-selenomethionine, while the others received a placebo daily during pregnancy and 12 months postpartum. The non-pregnant women received the supplement, serving as a positive control. Blood samples and twenty-four hour urine samples were collected monthly during pregnancy and at 3, 6, and 12 months postpartum for analysis of selenium and iodine. Selenium content in plasma and urinary excretion of selenium fell during pregnancy; however, total excretion of selenium was greater during pregnancy than postpartum. Urinary iodine excretion was much lower than reported previously in New Zealand. Due to large intra- and inter-subject variability, no trends in iodide excretion were observed. Factors which influence urinary excretion of selenium include dietary intake, but more closely, plasma concentrations of selenium (which is probably related to total selenium pool), creatinine excretion and therefore lean body mass, and glomerular filtration rate. The exact mechanism and sequence of events remains unclear and future studies incorporating new speciation techniques are necessary.     

Comparative in vitro responses of fetal, pregnant and non-pregnant rabbits' adrenal glands to steroidogenic agents

The in vitro secretion of aldosterone and corticosterone by the adrenal glands of fetal (day 30), pregnant and non-pregnant rabbits was examined under basal and stimulated conditions. In general, non-pregnant animals basally secreted less aldosterone than either pregnant or fetal rabbits, whereas basal corticosterone secretion by pregnant animals exceeded that of either fetal or non-pregnant animals. At similar doses of adrenocorticotropin (ACTH), fetal and pregnant adrenal glands produced comparatively more aldosterone than non-pregnant animals, while corticosterone secretion was accelerated to a greater degree in fetal rabbits than in the other groups. Angiotensin II had its greatest effect on the aldosterone secretory rates of fetal and non-pregnant animals without affecting corticosterone secretion in any group. Elevated potassium (K+) enhanced the secretory rates of aldosterone and corticosterone in fetal animals, while increasing only aldosterone secretion in non-pregnant rabbits. Serotonin accelerated aldosterone secretion in all animals, whereas it increased corticosterone secretion only in non-pregnant animals. These results suggest that (1) in fetal rabbits, the secretory rates of both aldosterone and corticosterone are regulated primarily by ACTH and to a much lesser extent by angiotensin II and K+, (2) the corticosterone secretory rates of pregnant and non-pregnant rabbits are controlled mainly by ACTH, and (3) aldosterone secretion by non-pregnant animals is regulated primarily by angiotensin II and secondarily by ACTH and K+, while in pregnant animals ACTH may be the primary regulator of aldosterone secretion as it is in the fetus.     

Daily changes in peripheral plasma progesterone concentrations in pregnant and pseudopregnant rabbits

Peripheral levels of plasma progesterone were found to be similar in pregnant New Zealand White and Dutch-belted rabbits. In early gestation progesterone concentrations rose rapidly, remained relatively constant and declined slowly during the latter third of pregnancy. Among pseudopregnant rabbits progesterone levels rose rapidly until day 11 and declined rapidly thereafter until day 19 at which time baseline values were obtained.     

Differences in the effects of vasopressin and oxytocin on rabbit myometrial activity and a possible mediation of prostaglandins

Uterine responses to vasopressin and oxytocin were monitored in non-pregnant and 3- or 6-8-day-pregnant rabbits by recording the intrauterine pressure. Oxytocin stimulated uterine activity in all groups, but the effect of vasopressin was stimulatory in non-pregnant animals, inhibitory in those 3 days post coitum and weakly stimulatory in those later in pregnancy. Inhibition of prostaglandin (PG) synthesis, by the administration of indomethacin, reduced the spontaneous uterine activity as well as the responses to oxytocin and vasopressin in the non-pregnant rabbits, but had little effect in the pregnant animals. During infusion of PGF-2alpha, PGE-1 or PGE-2 in 6-8-day-pregnant rabbits, the stimulatory response to vasopressin, although slight before the infusion, was inhibited whereas the stimulatory response to oxytocin remained virtually unchanged. The results suggest that vasopressin and oxytocin under certain hormonal conditions, are able to activated the uterine contractions by mechanisms in which the involvement of PG is not obligatory.     

Hematology and serum chemistry values of adult, pregnant and newborn New Zealand rabbits (Oryctolagus cuniculus)

Hematological and serum chemistry values were determined in adult female and pregnant New Zealand rabbits (Oryctolagus cuniculus) and their newborn at delivery. No significant difference was found between adult and pregnant hematological profiles. In the newborn, RBC were significantly lower and WBC, MCV and MCH higher than in their mother and adults. A characteristic protein profile was observed for the serum of each animal group, as well as for amniotic fluid. Lipoprotein pattern of the newborn was close to that of the dam, which differed from the adult female rabbit profile. The serum biochemical patterns are close to those of humans, suggesting that the New Zealand rabbit could be a reliable animal model for studies in the perinatal field involving monitoring of selected variables.     

Prostaglandin-induced luteolysis in pregnant and pseudopregnant rabbits and the resultant effects on the myometrial activity.

The effect of prostaglandin (PG)-induced luteolysis on the myometrial activity in 20--21-day-pregnant and 11--12-day-pseudopregnant rabbits was studied by intrauterine pressure (IUP) recording during PG infusions. The same dose of PG (10 micrograms/h during 8h) was also given to 7 non-pregnant (untreated) does that were used as controls. Peripheral plasma concentration of progesterone and oestradiol-17 beta were measured at 2-h intervals during the infusion. Plasma progesterone level decreased significantly within 2 h or the start of infusion in pregnant and pseudopregnant does and continued to decrease; at the end of 8 h, the concentrations were 31 and 41%, respectively, of the pre-infusion levels. The amplitude of uterine contractions increased significantly after 4 h in pseudopregnant does, increased slightly but insignificantly in the pregnant does and showed no significant change in the non-pregnant does during PG infusion. The amplitudes developed in the pregnant and pseudopregnant does were significantly different. The direct effect of progesterone (1--3 micrograms/h during 4 h) was also studied in 7 non-pregnant rabbits. After 2 h the amplitude of contractions had decreased markedly and the pattern of activity had become irregular. The results support the concept of a myometrial inhibitory factor other than progesterone in rabbit pregnancy and suggest that this factor(s) originates in conceptus.     

Some observations on the behaviour of hypothalamic enzymes during the time of blastocyst implantation in the rabbit

1. Hypothalami from pregnant and non-pregnant rabbits were homogenized in sucrose and separated into fractions by differential and density-gradient centrifugation. 2. The fractions were examined for enzymes capable of inactivating oxytocin. 3. Enzyme activity was detected in the supernatant and one particulate fraction of both pregnant and non-pregnant animals. 4. The specific activity of the enzymes increased during early pregnancy, and coincided with the time of blastocyst spacing and implantation in the uterus.     

Four methods for general anaesthesia in the rabbit: a comparative study

The efficacy and safety of pentobarbitone, ketamine/xylazine, fentanyl/fluanisone/diazepam, and halothane/nitrous oxide anaesthesia were compared in 4 groups of six New Zealand White rabbits. Heart and respiratory rates, body temperature, reflexes, blood pressure and blood gases were measured. Pentobarbitone appeared to be unsuitable for anaesthesia in rabbits, as 5 of the 6 rabbits to whom it was administered, required artificial respiration or died. The combinations of ketamine/xylazine and fentanyl-fluanisone/diazepam both produced unpredictable levels of anaesthesia together with a substantial decline in arterial blood pressure and PO2. Despite a severe drop in blood pressure (up to 37.5%), anaesthesia with halothane and nitrous oxide was found to be superior to the other anaesthetic agents.     

Concentrations of serum cortisol, progesterone, estradiol-17 beta, cholesterol and cholesterol ester in the doe during the reproductive stadium, in the fetal serum, in the amniotic fluid and in the milk of rabbits, as well as correlations between these parameters

1. Serum progesterone, estradiol-17 beta and cortisol, as well as cholesterol and cholesterol ester concentrations in pregnant and lactating rabbits (New Zealand white hybrids, n = 9), were measured. These parameters were also studied in the amniotic fluid, the milk and the fetal serum (28-day old fetuses). 2. Serum progesterone and estradiol-17 beta were significantly enhanced during gestation, while the content of cortisol showed a marked elevation at the end of pregnancy. The concentrations of these hormones decreased before parturition. 3. Serum cholesterol and cholesterol ester concentrations markedly decreased in the second half of gestation (74 and 76%, respectively) and elevated after parturition and in the first week of lactation.     

Influence of pregnancy, lactation and environment on haematological profiles in Danish landrace dairy goats (Capra hircus) of different parity.

1. Haematological analysis was performed in young and adult non-pregnant, non-lactating, early and late pregnant, early mid- and late lactating Danish landrace goats from five herds. The purpose was to determine whether their levels are significantly different in these states and the effect of age and parity on the changes. 2. The haematocrit, haemoglobin concentration, number of erythrocytes and leukocytes were higher in 8-12 month old non-pregnant and 1-2 year old pregnant goats than in adult pregnant and lactating goats of over 2 years of age. Haematocrit, haemoglobin concentration and the number of erythrocytes decreased in late pregnancy and early lactation. 3. At the same time mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration slightly increased. 4. The changes were directly proportional to parity, more in pluriparous than in primiparous goats. 5. After parturition the former group of parameters increased and the latter decreased. 6. There was an increase in the number of total leukocytes close to and after parturition due to neutrophils and lymphocytes and it was more pronounced in the first lactation than in pluriparous goats. 7. There were significant differences in many parameters between goats from different herds (within similar physiological states).     

Influence of pregnancy and sex steroids on concentration, motor effect and receptor binding of VIP in the rabbit female genital tract

The influence of sex steroid and pregnancy on the tissue concentration, uterine motor effect and receptor binding of VIP has been studied in the female genital tract of pregnant rabbits and oophorectomized rabbits during progesterone and/or oestrogen substitution. The concentration of immunoreactive VIP was high in the vagina and cervix, and lower in the uterine body of both pregnant and non-pregnant rabbits. A significant decrease in the VIP concentration (pmol/g wet weight) of the uterine body was observed toward term of pregnancy. The total uterine content of VIP, however, seems unchanged. Treatment of oophorectomized rabbits with ovarian steroids had no effect on the VIP concentration. The sensitivity for and potency of VIP on the relaxation of uterine muscle was significantly higher in oophorectomized rabbits treated with a combination of progesterone and oestrogen than in control rabbits. No difference was observed between non-pregnant and pregnant rabbits. The degradation and binding affinity for 125I-labelled VIP was highest in oophorectomized rabbits substituted with both oestrogen and progesterone. In the pregnant rabbits, the amount of receptors was decreased near term. In conclusion, sex steroids are able to influence the motor effect of VIP at the receptor level, but have no effect on the VIP concentration in the female genital tract.     

Barium responsiveness of the rat aorta and femoral artery during pregnancy

The barium responses of isolated aortic strips and femoral arteries from non-pregnant and pregnant rats were investigated. Barium caused concentration-related increases in tension of vessels from both pregnant and non-pregnant rats. The concentration-response curves of femoral arteries from non-pregnant and 3 week pregnant rats were not different; however contractility and slopes of concentration-response lines for thracic aortas from 1, 2 and 3 week pregnant rats were significantly less than those of aortas from non-pregnant rats. In addition, barium caused rhythmic contractions to develop in both femoral arteries and aortas of 3 week pregnant rats more frequently than vessels from non-pregnant rats. Rhythmic contractions did not develop in aortas from 3 week pregnant rats rats in calcium-free Krebs. Since the effects of barium on the electrical and mechanical activity of various muscles have been postulated to be similar to and/or dependent on calcium, these results may indicate that changes in calcium sensitivity of vascular smooth muscle occur during pregnancy. Such changes may contribute to the blood flow redistribution and other cardiovascular adaptations of pregnancy.     

Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand. I. Descriptive data.

A longitudinal observational study of 15 red deer (Cervus elaphus) farms was carried out in New Zealand for 2 years from Mar 1992. Management of hind mobs and their composition during mating, calving, and weaning were recorded. About 2700 hinds were individually monitored for live weight, body condition score and reproductive success. All hinds were pregnancy tested in June by ultrasound and classified as having conceived before May 1, after May 1, or as being not pregnant. Calving dates and dam-offspring pairs were recorded on four farms. The lactational status of hinds and live weight of calves were recorded at weaning. Mean pre-mating live weights of yearling hinds were 81.3-82.8 kg and of adult hinds 98.0-98.7 kg, respectively, for each year of study. The percentage of yearling and adult hinds conceiving before May ranged from 8.3 to 95.0% and from 77.6 to 98.4%, respectively, between farms. Overall, the proportion of yearling and adult hinds not pregnant was 15.3% and 3.2%, respectively. Pregnancy rates at scanning of adult hinds within mating mobs were generally over 90%, and 41.7% of mating mobs had 100% pregnancy rates. In contrast, the pregnancy rates of yearling hind mobs were more variable, with five mobs below 50%, and 34.1% of mating mobs achieving 100% pregnancy rate. Estimated in utero loss rates from pregnancy diagnosis to calving were 0.66 and 0.79% for yearling and adult hinds, respectively. From four farms, median calving dates of yearling and adult hinds were Dec 13 and Nov 30, respectively. Overall, calf survival rates to weaning of yearling and adult offspring were 84.1 and 91.6%, respectively, while the reproductive efficiencies (number of calves weaned per hind mated) were 70 and 83.6%, respectively. Farm mean weaner live weights standardised on Apr 1 ranged from 42-59 kg and 39-51 kg for stags and hinds, respectively. These data are currently the best estimates of reproductive parameters of New Zealand red deer herds, and highlight a wide variability in reproductive indices between farms.     

慢性心衰新西兰家兔某些生化指标和心功能的改变

目的：研究慢性心衰实验动物某些生化指标和心功能的变化,为慢性心衰的诊断提供依据。方法：使用阿霉素制备新西兰兔慢性心衰模型,将20只新西兰兔随机分为模型组（n=15）和对照组（n=5）,分别耳缘静脉注射阿霉素（ADR）和生理盐水1 ml/kg,每周2次,共8周。随后进行心肌酶、颈动脉压、心电和心音信号的检测。结果：经统计学分析得知,两组的各项指标均有显著性差异（P<0.05）。结论：慢性心衰导致新西兰兔心肌受损,收缩功能和舒张功能下降,心脏储备指标有助于慢性心衰的诊断。     

Detection of early pregnancy-specific proteins in Holstein milk

Bovine pregnancy is commonly diagnosed by rectal palpation or ultrasonography and changes in progesterone concentration. To determine a simpler and less expensive diagnostic method, we sought to identify early pregnancy-specific proteins in bovine milk by comparing samples collected from pregnant and non-pregnant Holstein cattle. Of the 600-700 protein spots visible on 2-DE gel images, 39 were differentially expressed in milk from pregnant and non-pregnant cattle. Antibodies generated against synthetic peptides of milk whey proteins expressed specifically during pregnancy were used to confirm protein expression patterns. Western blot analysis showed that the levels of expression of lactoferrin (lactotransferrin) and alpha1G T-type calcium channel subunit (alpha-1G) were higher in samples from pregnant than non-pregnant cattle. These findings suggest that assays for pregnancy-specific milk proteins may be used to diagnose pregnancy in cattle.     

Thiopental anaesthesia and the acid-base balance in the blood of experimental dogs.

An analysis of basic parameters representative of the acid-base balance was made in arterial blood samples from 140 clinically healthy dogs, under a general intravenous Thiopental anaesthesia. The following mean values +/- S.E.M. were obtained: pH = 7.33 +/- 0.01; pCO2 = 47.16 +/- 0.95; base excess = -2.12 +/- 0.27; buffer base = 46.63 +/- 0.37. The results showed a prevalent trend of lower values of pH, base excess and buffer base and higher values of pCO2 than those found commonly in human clinical practice. Special attention was paid to the respiratory component of the acid-base balance (ABB) revealing certain undesirable side effect of Thiopental anaesthesia.     

Ontogeny of hematological cell and biochemical profiles in maternal and fetal baboons (Papio species)

The normal ranges of hematological cell profiles and biochemistry are documented in adult non-pregnant, pregnant, juvenile, and neonatal baboons. Despite the extensive use of the baboon as a model for the study of various aspects of pregnancy, there is no data from paired mothers and their fetuses at different stages of gestation. Hematologic and biochemical profile data were obtained from eight non-pregnant female baboons, 37 mothers and 38 fetal baboons at 30 +/- 2, 90 +/- 2, 125 +/- 2, and 175 +/- 2 days of gestation (mean +/- range; dGA; term, 180 dGA). Changes observed in fetal and maternal blood during normal baboon pregnancy were similar to those reported in human pregnancy. The level of alkaline phosphatase was two times higher in fetal blood circulation than that reported in human pregnancy.     

Relationship of bispectral index values, haemodynamic changes and recovery times during sevoflurane or propofol anaesthesia in rabbits

The aim of this study was to determine and compare the degree of hypnosis achieved during propofol or sevoflurane anaesthesia in rabbits using bispectral index (BIS), and to evaluate its usefulness as a predictor of both haemodynamic changes during anaesthesia and recovery times. Twenty adult male New Zealand White rabbits, average weight 4.4 +/- 0.4 kg, were used for this study. Animals were randomly allocated to one of two groups with 10 rabbits/group. An electroencephalographic recording was obtained from each conscious rabbit prior to drug administration. All animals received buprenorphine as a preanaesthetic medication (0.05 mg/kg, intravenous [i.v.]). Anaesthesia was induced with propofol (8 mg/kg, i.v.) in all animals; 10 rabbits were maintained with sevoflurane via inhalation (1 minimum alveolar concentration--end-tidal sevoflurane concentration of 3.7%--at a fresh gas flow rate of 3 L/min; group I), and 10 were maintained with i.v. propofol (0.6 mg/kg/min; group II). The rabbits were orotracheally intubated and spontaneous ventilation was maintained throughout the study (100% oxygen). After abdominal surgery through a ventral midline laparotomy, rabbits were allowed to recover from anaesthesia. Cardiovascular variables and BIS values were recorded at intervals throughout the procedure, as was the duration of recovery from anaesthesia. In both groups, mean BIS values were significantly decreased immediately after induction, compared with baseline values obtained during consciousness. Anaesthetic depth (evaluated by clinical observation) was similar in both groups; however, group II rabbits had significantly higher (P<0.001) BIS values from 30 s before incision until anaesthesia was discontinued. There was no significant difference in BIS recorded 1 and 5 min after incision as compared with values obtained 30 s before incision in either group. During sevoflurane or propofol administration, correlations were found between BIS values and mean arterial blood pressure (MABP), and between BIS values and heart rate (HR). Mean BIS values at discontinuation of administration of the anaesthetic agent were greater in group II (69.1 +/- 6.0) than in group I (49.3 +/- 2.2). However, recovery from anaesthesia was significantly longer in group II (38.4 +/- 7.2 min) than in group I (11.5 +/- 2.5 min). In conclusion, BIS can be used to differentiate between conscious and unconscious states during anaesthesia in rabbits. BIS values derived from an electroencephalogram at the end of anaesthesia were not useful for predicting the speed of anaesthetic recovery in sevoflurane or propofol-anaesthetized rabbits undergoing abdominal surgery. Despite the correlation found between BIS and haemodynamic parameters, its usefulness as a predictor of clinically important changes in arterial blood pressure and HR in anaesthetized rabbits was limited.