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1.
The finely lobulated kidneys of American river otters (Lutra canadensis) are not visualized on plain abdominal radiographs. Similar values for blood urea nitrogen (BUN), creatinine, and uric acid were obtained on different analytical systems used in 1984 and 1985. The mean +/- SD for measured plasma osmolalities (309.80 +/- 8.86 mOsmol/kg) of otters in 1985 was significantly (P less than 0.01) less than that of calculated serum osmolalities in the same 1985 specimens (321.61 +/- 5.64 mOsmol/kg) and in 1984 specimens (322.20 +/- 7.16 mOsmol/kg). Urine specific gravities and osmolalities were highly correlated (r = 0.92). On routine urinalysis, protein and bilirubin were frequent chemical findings, and urobilinogen was present in all urine samples. White and red blood cells and epithelial cells were frequent findings on urine microscopic examinations. Proteus mirabilis was cultured from four of four female otters with genitourinary infections. The mean +/- SD creatinine values for paired serum and urine samples (n = 13) were serum creatinine (Scr) 0.66 +/- 0.09 mg/dl and urine creatinine (Ucr) 186.9 +/- 55.6 mg/dl. Corresponding values for serum electrolytes (Se) and urine electrolytes (Ue) yielded mean +/- SD calculated renal fractional clearances (FC = Ue/Se x Scr/Ucr) of sodium 9.65 +/- 5.81 x 10(-4), potassium 4.15 +/- 2.01 x 10(-2), chloride 10.81 +/- 5.33 x 10(-4), calcium 4.52 +/- 4.46 x 10(-3), and phosphate 6.58 +/- 3.44 x 10(-3).  相似文献   

2.
We examined the use of the ratio of serum urea to serum creatinine as a physiological biomarker of fasting to monitor temporal patterns in the feeding ecology of polar bears (Ursus maritimus). Blood was collected from 436 polar bears in the eastern Beaufort Sea during April and May of 1985–1986 and 2005–2006. The proportions of polar bears fasting were 9.6% in 1985, 10.5% in 1986, 21.4% in 2005, and 29.3% in 2006. We used stepwise logistic regression analysis to evaluate factors that could influence the binary response variable of fasting or not fasting. Significant predictor variables of fasting were: the 2005 and 2006 capture years, solitary adult male bears, and adult male bears that were accompanying an estrous female. The increased number of polar bears in a physiological fasting state from all sex, age, and reproductive classes in 2005 and 2006 corresponded with broad scale changes in Arctic sea ice composition, which may have affected prey availability. The higher proportion of adult males fasting from all years was attributed to spring breeding behavior.  相似文献   

3.
The rapidity with which the kidney alters sodium excretion (ENa) in response to changes in dietary Na was studied in Merino sheep by analyzing hourly ENa for three control days, and then for three days after a change in Na intake. On a control diet of 117 mmol Na, sheep had a pre-feeding ENa of 3.5 mmol/hr., a striking post-feeding natriuresis that began 2 hours after feeding (less than 0.01), peaked at 4 hrs. and then declined to pre-feeding levels 7 hrs. after feeding. When in balance on a high Na diet the feeding of a low Na meal resulted in marked depression of ENa within 4 hours after feeding. On a low Na diet, a 100 mmol Na meal resulted in an increase in ENa within 4 hours but a 50 mmol Na meal did not. Thus, the sensitivity of post-feeding natriuresis is between 50 and 100 mmols Na. As post feeding natriuresis is a naturally occurring physiological event it should provide a useful paradigm for the investigation of mechanisms controlling Na balance.  相似文献   

4.
Polar bears (Ursus maritimus) from several subpopulations undergo extended fasting during the ice-free season. However, the animals appear to conserve protein despite the prolonged fasting, though the mechanisms involved are poorly understood. We hypothesized that elevated concentrations of corticosteroid binding globulin (CBG), the primary cortisol binding protein in circulation, lead to cortisol resistance and provide a mechanism for protein conservation during extended fasting. The metabolic state (feeding vs. fasting) of 16 field sampled male polar bears was determined based on their serum urea to creatinine ratio (>25 for feeding vs. <5 for fasting). There were no significant differences in serum cortisol levels between all male and female polar bears sampled. Serum CBG expression was greater in lactating females relative to non-lactating females and males. CBG expression was significantly higher in fasting males when compared to non-fasting males. This leads us to suggest that CBG expression may serve as a mechanism to conserve protein during extended fasting in polar bears by reducing systemic free cortisol concentrations. This was further supported by a lower serum glucose concentration in the fasting bears. As well, a lack of an enhanced adrenocortical response to acute capture stress supports our hypothesis that chronic hunger is not a stressor in this species. Overall, our results suggest that elevated serum CBG expression may be an important adaptation to spare proteins by limiting cortisol bioavailability during extended fasting in polar bears.  相似文献   

5.
The locomotor system of sanguivorous leeches is presented with a unique challenge: how to maintain mobility while coping with a >500% increase in body mass during feeding. A meal of this size is likely to disrupt the function of the muscular hydrostat during swimming, reducing speed and increasing predation risks. We quantified the effects of feeding to satiety on swimming kinematics, and the time course of recovery of swimming performance post-feeding in the medicinal leech Hirudo verbana . There was a 5.07 ± 0.04-fold increase in mass during feeding (mean ± sem , n =7). Despite this, leeches were able to swim immediately after feeding, reaching 27% of their pre-feeding speed. Reduced speed was a consequence of a reduction in both swimming cycle frequency and stride length to 69 and 42% of the pre-feeding values, respectively. Recovery of swimming ability was rapid, despite a prolonged increase in body mass. Fifty per cent restoration of swimming speed was achieved in c . 1 h while body mass was still 4.2-fold greater than before feeding. Rapid mass and volume reduction immediately post-feeding, and the properties of the obliquely striated swimming muscles appear to aid recovery of swimming performance. Such features that aid post-feeding recovery of mobility may have been important in the evolution of leech sanguivory.  相似文献   

6.
This study was done to evaluate the effects of soy protein hydrolyzate with bound phospholipids (c-SPHP), on the serum cholesterol levels in hypercholesterolemic subjects over a three-month period. Subjects were Taiwanese adult male volunteers whose serum total cholesterol levels were above 220 mg/dl. Twenty-one subjects were divided into three groups randomly, and each group was given c-SPHP zero, 3, or 6 g per day. Test diets were orally administered in a powdered drink form that contained c-SPHP or casein hydrolyzate (placebo). The subjects were given the test diet four times daily. The study consisted of a two-week pre-feeding period, a three-month feeding period, followed by a two-week post-feeding period. After 3 months of c-SPHP administration, 3 g per day, serum total cholesterol decreased significantly from the initial level (15.0%, p<0.01) and compared with the placebo group (p<0.05). Furthermore, LDL-cholesterol decreased significantly (27.7%, p<0.01) and the LDL/HDL ratio also decreased significantly (47.4%, p<0.01) from the initial levels. These effects of c-SPHP were dose-dependent. This study suggests that c-SPHP has remarkable improving effects on the serum cholesterol levels in hypercholesterolemic subjects.  相似文献   

7.
Predation on ringed seals ( Phoca hispida ) was examined in Barrow Strait between March and May 1984 to 1986. Polar bears were the most important predator. Evidence of bear predation was observed at 18–30% of the ringed seal subnivean structures we located. Ten to 24% of predation attempts were successful, with pups making up 75% to 100% of the seals killed. Bears killed an average of 0.08 to 0.51 seals/km2, which comprised 8 to 44% of the estimated annual pup production. Bears were successful on average in 11.3% of their attempts to kill pups hidden inside birth lairs. On southeast Baffin Island where snow was soft and pups were exposed, bears were successful in 33.5% of their attempts to kill a seal. Negative correlations were found between mean snow depth and predation by polar bears ( r = -0.896, P = 0.04, n = 5) in 1985, and between snow depth and the number of predation attempts ( r = -0.613, P = 0.02, n = 14) in 1986.  相似文献   

8.
Temperature and food availability are two important factors which affect fish growth and therefore are expected to influence habitat choice in fish. In this study, shoals of 16 juvenile roach, Rutilus rutilus , were given a choice between two chambers that differed in temperature by 1·5°C or 3°C whereas food availability was the same in both chambers (ratio 1 : 1) or higher in the colder one (ratio 4 : 1). The number of fish in each chamber was recorded for 10 min each during a pre-feeding, feeding and post-feeding period. Roach generally preferred the warmer over the colder chamber during the pre-feeding periods. Temperature had a significant effect on the distribution of fish during all three time periods whereas food availability was a significant factor only during the feeding period. The important role of temperature was emphasized further by the fact that a relatively small difference in the temperature gradient of 1·5°C had a stronger effect on fish distribution than a four times higher feeding rate during the feeding period. The implications for growth rates of such short-term decision-making of roach are discussed.  相似文献   

9.
Twenty-four serum chemistries were measured in blood samples collected from 20 adult female black bears (Ursus americanus) and their offspring, including 14 yearlings and 37 cubs, in northeastern Pennsylvania during winter 1984. Four other captive adult females were bled before, during, and after they were subjected to unseasonably warm temperatures during February. Levels of serum urea nitrogen (SUN) and creatinine were lower (P less than 0.05), and iron was higher (P less than 0.05) in male cubs compared to female cubs; serum chemistries were similar (P greater than or equal to 0.05) between sexes for yearlings. Total protein, albumin and creatinine levels increased with age of bears, whereas chloride, alkaline phosphatase, potassium, inorganic phosphorus and SUN/creatinine were higher (P less than 0.05) in cubs than in yearlings and adults. The relatively high serum calcium in cubs was probably related to rapid bone development and dietary intake of calcium during winter dormancy in cubs. Low serum calcium in adults was attributed to lactation and a lack of dietary intake. Urea/creatinine ratios averaged 5.5 and 4.6 for yearling females and males, respectively, 6.3 for adult females, and 29.0 and 22.8 for female and male cubs, respectively. Levels of serum chemistries of black bears apparently are relatively stable during winter denning, when bears are without food or water and do not urinate or defecate for several months. This stability indicates that black bears are resistant to the extremes in extrinsic environmental conditions. Abnormal blood chemistry values may indicate metabolic stresses that are not being controlled by bears.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
Abstract During long post-feeding periods, adult tephritid flies (and apparently other non-blood feeding Diptera and even Hymenoptera) engage in behaviour consisting of oral extrusion and aeration of liquid droplets of varying size (‘bubbling’), proboscis pumping, and occasional deposition of regurgitate on the substrate that is followed by subsequent re-ingestion. Unlike evaporative cooling, which occurs in some insects when heat-stressed, these regurgitation behaviours take place regularly at moderate temperatures. To our knowledge, the significance of these behaviours has not been studied. We suggest that through bubbling behaviour, fully gorged Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) flies eliminate excess water by evaporation to concentrate nutrients suspended in dilute solution, and release crop volume to allow resumption of fluid feeding or minimize the water load while foraging for other resources. Fly weights were measured continuously during pre- and post-feeding periods and in relation to occurrence of regurgitation behaviours. Fly weight losses during pre-feeding were an order of magnitude lower than post-feeding weight losses when flies exposed regurgitated liquid crop contents to air. During a bout of droplet extrusions, lasting on average 23 min, weight loss averaged 66% of the weight of liquid ingested by a fly in the preceding meal. Fly weight loss while bubbling was significantly correlated with duration of bubbling, temperature and relative humidity during post-feeding, and initial fly weight (adj. R2 = 0.95). Fly age, volume of liquid ingested and rate of pre-feeding weight loss did not significantly improve predicted weight loss through bubbling. Findings are discussed in relation to other behaviours adopted by fluid-feeding insects to eliminate excess water.  相似文献   

11.
The relationship between time of feeding and aggression in a one-male unit of captive hamadryas baboons was studied to determine if feeding once a day, at a designated time and in measured amounts leads to a high level of aggressive behavior. The performance of maintenance behaviors did not differ between pre-feeding and post-feeding periods, however, aggressive behavior significantly decreased after feeding.  相似文献   

12.
The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter‐specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic‐feeding ice‐associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (≥7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983–1999 and 2000–2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic‐level productivity in these marine ecosystems.  相似文献   

13.
Mammals in a patchy environment are often required to make regular spatial movements in order to obtain necessary resources. Polar bears (Ursus maritimus) are known to move distances of several hundred kilometres to locate favourable feeding areas or suitable habitats for female maternity denning. This paper describes the routes followed by adult female Polar bears in spring from a region in north-eastern Manitoba, Canada, where they had denned over winter, to the sea ice of Hudson Bay where they could hunt seals. Over a five-year period, 74 tracks in snow were followed for a total distance of 1081 km. Most tracks ( n = 64) were made by adult females accompanied by recently born cubs-of-the-year. These family group tracks followed relatively parallel and straight courses toward the sea with a mean heading of 39° but did not follow the shortest straight line distance to the sea. The remaining tracks were made by solitary bears, probably adult females. These tracks had a mean heading similar to that of family groups but travelled more convoluted courses. Solitary bears also frequently dug snow caves and multiple shallow snow pits along their routes, structures never observed along the routes of family groups.  相似文献   

14.
Although mammalian urinary tract epithelium (urothelium) is generally considered impermeable to water and solutes, recent data suggest that urine constituents may be reabsorbed during urinary tract transit and storage. To study water and solute transport across the urothelium in an in vivo rat model, we instilled urine (obtained during various rat hydration conditions) into isolated in situ rat bladders and, after a 1-h dwell, retrieved the urine and measured the differences in urine volume and concentration and total quantity of urine urea nitrogen and creatinine between instilled and retrieved urine in rat groups differing by hydration status. Although urine volume did not change >1.9% in any group, concentration (and quantity) of urine urea nitrogen in retrieved urine fell significantly (indicating reabsorption of urea across bladder urothelia), by a mean of 18% (489 mg/dl, from an instilled 2,658 mg/dl) in rats receiving ad libitum water and by a mean of 39% (2,544 mg/dl, from an instilled 6,204 mg/dl) in water-deprived rats, but did not change (an increase of 15 mg/dl, P = not significant, from an instilled 300 mg/dl) in a water-loaded rat group. Two separate factors affected urea nitrogen reabsorption rates, a urinary factor related to hydration status, likely the concentration of urea nitrogen in the instilled urine, and a bladder factor(s), also dependent on the animal's state of hydration. Urine creatinine was also absorbed during the bladder dwell, and hydration group effects on the concentration and quantity of creatinine reabsorbed were qualitatively similar to the hydration group effect on urea transport. These findings support the notion(s) that urinary constituents may undergo transport across urinary tract epithelia, that such transport may be physiologically regulated, and that urine is modified during transit and storage through the urinary tract.  相似文献   

15.
黑龙江省熊类年龄构成、性比及繁殖情况的初步研究   总被引:4,自引:2,他引:2  
熊类是重要的狩猎动物,肉、皮、骨、脂均可利用,熊掌和熊胆尤为名贵,因而具有很高的经济价值。 目前,国际上对于熊类生态学的研究日益深入。近二十年来多次举行国际熊类研究专题讨论会并出版了论文集。研究方向集中于熊类的群体生态,行为生态及种群的管理方面并正朝着集约管理和合理利用的方向发展。  相似文献   

16.
BackgroundLead (Pb) is a worldwide concern due to its persistent property in the environment. However, due to diminutive evidence and elusiveness, the impact of lead exposure on the biochemical and haematological parameter in school-age children is not well established.AimThis study primarily aimed to investigate blood lead (BL) in children and its association with haematological and biochemical parameter.MethodsA total of 43 children (4–12 years) were recruited in each control and study group. Furthermore, the study group were subdivided into two groups (group A (<10 μg/dl) and group B (>10 μg/dl)). BL level, haematological parameter including haemoglobin, packed cell volume, red blood cells, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, total leukocytes count, neutrophils, lymphocytes, monocytes, mean corpuscular volume, red cell distribution width, eosinophil’s, platelets in the whole blood and biochemical parameter such as liver function test (total bilirubin, alkaline phosphatase, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, total protein, albumin) and kidney function test (sodium, potassium, blood urea nitrogen, creatinine) in serum were measured using anodic stripping voltammeter (ASV), Cell-Dyn Ruby Haematology analyser, Beckman coulter Unicel Dxc 800 Synchron Clinical analyser respectively.ResultsThe arithmetical mean of BL level was 19.93 ± 9.22 μg/dl (median: 17.5 μg/dl; range 9.1–37.4 μg/dl). Only 21 % children had BL levels <10 μg/dl and there were 79 % children with BL levels >10 μg/dl. Blood mean corpuscular haemoglobin concentration, Neutrophils, Monocytes were significantly higher between the control and study group. Additionally, haemoglobin, packed cell volume, red blood cells, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, Lymphocytes and mean corpuscular volume intensities were significantly lower in >10 μg/dl group whereas total leukocytes count, neutrophils, monocytes, red cell distribution width, eosinophil’s, platelets levels were statistically higher (p < 0.001).Serum alkaline phosphatase, serum glutamic-oxaloacetic transaminase, total protein, were higher (p < 0.05) and sodium, albumin were significantly lower in the study group. The mean value of sodium, potassium, total bilirubin, alkaline phosphatase, serum glutamic-pyruvic transaminase, total protein and blood urea nitrogen, creatinine in two groups (<10 μg/dl and >10 μg/dl) was not significantly different. Serum glutamic-oxaloacetic transaminase level was significantly higher (p = 0.015) while albumin levels were significantly lower (p = 0.034) in >10 μg/dl group. A statistically significant correlation of BL levels with all haematological parameters was also observed. Creatinine is positively and albumin was negatively correlated with BL levels.ConclusionThe outcomes specify that high BL levels were significantly associated with higher haematological and biochemical indices in exposed children. However, lead like noxious metals severely affected the haematological, kidney and liver health of children.  相似文献   

17.
喂饲高脂高胆固醇饮食是诱发实验性动脉粥样硬化(简称AS)的基本方法。在诱发AS过程中,血清脂质的改变不但有种属差异,也存在个体反应性的差异。猴是用于AS研究最理想的实验动物。喂以高胆固醇饮食后,有些猴血清胆固醇上升速度明显高于一般同种猴,称高反应猴(High-responding rhesus monkey);另一些猴的血清胆固醇上升十分缓慢,低于同种猴的一般反应速度,称低反应猴(Low-responding rhesusmonkey)。关于高反应猴(简称HI)及低反应猴(简称LO)在诱发AS过程中血清胆固醇反应的差别,国外已有报道。(Baker et al.,1981;Bhattacharyya et al.,1977;  相似文献   

18.
J. E. Fay  A. Travill 《CMAJ》1967,97(2):78-80
The urine/plasma creatinine ratio (U/P Cr), the urine sodium concentration (UNa), and the diuretic response to mannitol infusion in 23 patients were reviewed in an attempt to differentiate functional renal failure (FRF) from acute tubular necrosis (ATN). FRF was diagnosed if the plasma urea nitrogen (PUN) or serum creatinine stabilized within 72 hours. When renal failure persisted longer, patients had ATN. Subjects dying within 72 hours were excluded. Ten patients had ATN and five survived. The minimum duration of renal failure among survivors was 10 days. None responded to mannitol. Of 13 patients with FRF, 11 survived. Seven of 12 who received mannitol responded with a diuresis. The mean UNa in the patients with ATN was 51.4 mEq./1. ± 9.48 (SE). The mean U/P Cr was 11.2 ± 1.12. In patients with FRF, the mean UNa was 14.0 mEq./1. ± 4.2 and the mean U/P Cr was 42.5 ± 11.5. A significant overlap was present between the two groups. When UNa was factored by the U/P Cr, the resultant ratio was significantly different for the two groups of patients (P < 0.01), and this proved to be a useful clinical index with which to distinguish FRF from established ATN.  相似文献   

19.
Previous research into oral persistence in pigs has shown that the relationship between motivation and performance of stereotypy is not a simple one, and that non-specific motivational factors such as arousal may be important. For chronically food-restricted sows the time before food arrives is characterised by increasing excitement and arousal which may be carried over into the post-feeding period facilitating the performance of persistent oral behaviour. To investigate this possibility, arousal was manipulated by delaying feeding. Five and 15 min delays were used and sows experienced delayed feeding 1 day in every 4. Principal components analysis (PCA) was used to group the behaviour data into two factors, ACTIVITY/CHEW and NOSE/ROOT/PEN and these scores were then analysed using ANOVA as well as the appropriate individual behaviours. The delay of feeding increased the rate of eating, presumably reflecting increased arousal (P<0.05). ACTIVITY/CHEW scores were highest in 5 min delay sets, and an interaction between day of set and delay length indicated that ACTIVITY/CHEW scores peaked on different days within a set (P<0.05). Time spent chewing was highest on the day of delay (P<0.05), while standing was highest in days 1 and 2 post-delay (P<0.05). The NOSE/ROOT/PEN scores were lower on the day of delay than on other days (P<0.05), and were lowest in the first delay set than in sets later in the trial (P<0.01). It appeared that increasing arousal in the pre-feeding period does affect activity and oral behaviours in the post-feeding period. However, some of the effects appeared in a more extended and diffuse manner, perhaps due to the general disturbance created by the experimental regime and the sows' experience of long-term food restriction.  相似文献   

20.
【目的】对比分析饥饿和未饥饿的拟小食螨瓢虫Stethorus parapauperculus成虫取食朱砂叶螨Tetranychus cinnabarinus前后的运动格局变化,为探明其搜索行为的生态学机制提供参考。【方法】基于Nakamuta装置原理,跟踪并绘制拟小食螨瓢虫成虫取食前后的运动轨迹,采用ArcGIS空间分析模块对运动轨迹进行处理,获取其统计参数,对比分析该瓢虫在两种状态下取食前后的搜索距离、搜索速度、搜索角度变化等特征,并阐述其搜索行为特性。【结果】饥饿24 h和未饥饿瓢虫取食单头朱砂叶螨所需时间分别为(5.99±0.91)min和(2.25±0.58)min。饥饿24 h的瓢虫在取食前多呈直线或锐角行走,运动轨迹主要分布于试验区域近边缘处,且各停点间曲线距离、搜索速度均大于取食后;取食后掉头次数频繁,活动角度转换增大,运动轨迹主要在猎物附近区域进行搜索,且在取食后60~75 s的搜索距离、搜索速度与取食前均存在显著差异。未饥饿状态瓢虫取食前后运动轨迹角度波动较大,无明显规律,且各停点间的曲线长度、搜索速度经t检验无显著差异。【结论】拟小食螨瓢虫成虫对猎物的搜索行为受其饥饿状态的影响。饥饿状态下,取食前为广域型搜索,取食后一段时间内为地域集中型搜索;未饥饿状态下的瓢虫取食前后的搜索行为则无明显规律,其搜索类型兼有广域和地域集中型搜索特征,具有一定随机性。  相似文献   

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