Liquoid-Induced Arterial Lesions and the Generalized Shwartzman Reaction

Mural necrotic lesions were produced in renal afferent arteries in rabbits, pigs and blue foxes, by intravenous injections of Liquoid. These lesions were frequently accompanied by thrombosis in the affected arterial segments and invariably by “microthrombosis” in glomerular capillaries. Mural arterial lesions were always present in cases with evident macroscopic necrotic changes of the renal cortex. Necrotic arterial lesions, with thrombosis, were also observed in pulmonary arteries in all the animal species used in these experiments, i.e. rabbit, pig, blue fox, mouse and ferret.     

Adiponectin and peptide YY in the fasting blue fox (Alopex lagopus)

Adiponectin (Acrp30) and peptide YY (PYY) are weight-regulatory hormones participating in the control of energy homeostasis. This study investigated the effects of long-term wintertime fasting on plasma Acrp30 and PYY levels in the carnivorous blue fox, a farm-bred variant of the arctic fox (Alopex lagopus). Plasma Acrp30 and PYY concentrations were determined with radioimmunoassays during a 22-day period of fasting, which led to a 20.3% reduction in body mass of the animals (n=32). Sixteen fed blue foxes served as the control group. Acrp30 and PYY were present in blue fox plasma at similar or lower levels as reported previously for other mammals. Fasting had no acute effects on Acrp30 or PYY concentrations of the blue foxes. However, the Acrp30 levels of the fasted blue foxes were 24%-48% higher than in the fed animals between days 8-22 of fasting. Fasted blue foxes also had 6.2-fold higher plasma PYY concentrations after 15 days of fasting. Acrp30 and PYY seem to play roles in the body weight-regulation of the blue fox during long-term fasting, but their specific functions and physiological significance remain to be determined.     

Comparative nutrient digestibility of arctic foxes (Alopex lagopus) on Svalbard and farm-raised blue foxes (Alopex lagopus)

Arctic foxes from Svalbard (n=4) and farmed blue foxes (n=4) was used in a digestibility experiment with a high-carbohydrate feed to add more information to the nutritional physiology of the arctic fox, and to compare its digestive capacity with that of the farmed blue fox. The arctic fox has a diet containing mainly protein and fat from mammals and birds, while farmed blue foxes have been exposed to an omnivorous dietary regime for more than 80 generations. The experiment showed in general no difference in digestive capacity for protein and fat between the foxes (P>0.05), but for carbohydrates, including starch and glucose, the blue fox revealed higher digestibility values. The superior digestive capacity for carbohydrates in blue fox might be a result of a long-term selection of animals digesting dietary carbohydrates more efficiently, or that an early age exposition to dietary carbohydrates has given permanent improvement of the carbohydrate digestion in the gut.     

Inter- and intraspecific competition between the fox species Alopex lagopus and Vulpes vulpes: an evaluation trial under penned conditions

This study compared competition capacity and dominance relations between arctic foxes (Alopex lagopus) and red foxes (Vulpes vulpes). Experiments were carried out in semi-natural earthen floor enclosures using farm-bred colour types of both species (blue fox and silver fox) as subjects. Results of the dominance scoring and open field behaviour after weaning in August-September showed that blue foxes dominated over silver foxes. Thereafter, the situation gradually became reversed and silver foxes were dominant during the breeding and whelping seasons. Housing both species together from weaning produced more curious animals as compared to when these species were placed in common quarters after the autumn equinox. In the case of blue foxes, the male dominated highly over all females. In silver foxes, the difference in dominance between the sexes was, however, less pronounced. The most dominant individuals in the study groups were typically among the heaviest. Breedings and whelpings succeeded better in silver than in blue foxes. However, none of litters born survived more than one week. The present results support the conclusion that when both fox species are housed together, Vulpus vulpus tends to dominate over Alopex lagopus. Received: 22 March 1996/Accepted: 30 June 1996     

Acute exposure to 50 Hz magnetic field does not affect hematologic or immunologic functions in healthy young men: A circadian study

Some epidemiological studies report a relationship between magnetic field exposure and such human diseases as leukemia and immune system disturbances. The few published studies on animals do not demonstrate field exposure-related alterations in hematologic and immune systems. The data presented here are part of a broader study designed to investigate the possible effects of acute exposure to a 50 Hz linearly polarized magnetic field (10 μT) on hematologic and immunologic functions. Thirty-two young men (20–30 years old) were divided into two groups (control group, i.e., sham-exposed, 16 subjects; exposed group, 16 subjects). All subjects participated in two 24 h experiments to evaluate the effects of both continuous and intermittent (1 h “off” and 1 h with the field switched “on” and “off” every 15 s) exposure to linearly polarized magnetic fields. The subjects were exposed to the magnetic field (generated by three Helmholtz coils per bed) from 23:00 to 08:00 while lying down. Blood samples were collected during each session at 3 h intervals from 11:00 to 20:00 and hourly from 22:00 to 08:00. No significant differences were observed between sham-exposed (control) and exposed men for hemoglobin concentration, hematocrit, red blood cells, platelets, total leukocytes, monocytes, lymphocytes, eosinophils, or neutrophils. Immunologic variables [CD3, CD4, CD8, natural killer (NK) cells and B cells] were unaltered. To our knowledge, this study is the first to document the effects of a 50 Hz magnetic field on the circadian rhythm of human hematologic and immune functions, and it suggests that acute exposure to either a continuous or an intermittent 50 Hz linearly polarized magnetic field of 10 μT, at least under the conditions of our experiment, does not affect either these functions or their circadian rhythms in healthy young men. © 1996 Wiley-Liss, Inc.     

Blue foxes’ motivation to gain access to solid floors and the effect of the floor material on their behaviour

Farmed blue foxes are willing to work to gain access to a sand floor from a wire mesh floor. It is not clear whether the foxes work for the sand floor because of its solidity or because it enables them to perform certain behaviours, e.g. exploration and digging. Here, we measured blue foxes’ motivation to gain access from a wire mesh floor to a floor with 15–30 cm deep sand, a floor with 3–4 cm deep sand, a solid concrete floor, and another wire mesh floor. In addition, we analysed the foxes’ behaviour on these floor materials. Seven male blue foxes were trained and tested in self-constructed operant apparatuses. In an apparatus, the fox could move a bottomless test cage from a wire mesh floor to a neighbouring, alternative floor material for a 4-min visit by pressing a lever in the test cage for a fixed number of times (Fixed Ratio, FR). The foxes worked for each floor material for 12 days. In each daily test session, the foxes were exposed to work on one of the four workloads (FR 6, 12, 24, 48), for 3 h. The behaviour of the foxes was analysed during the 4-min visits on each floor material. The results showed that there was no difference between the floor materials, either in the demand elasticity of the fragment of the demand curve (ranging from −0.46 to −0.33), or in the intensity of the demand. However, the foxes’ behaviour varied between the floor materials. More digging, play, rooting (exploration with the muzzle), and vole jumping were observed on the floor materials with sand, than on the concrete floor and the wire mesh floor. Both the presence and the depth of the sand layer stimulated these behaviours. It is concluded that juvenile blue foxes do not value solid floor materials more than a wire mesh floor. However, the sand floor stimulates more digging, play, vole jumping, and exploration than the concrete floor or wire mesh floor. Furthermore, the depth of sand may be an important factor in eliciting these behaviours. Access to a floor material with sand may improve the welfare of farmed blue foxes by providing the possibility to perform species-specific behaviours.     

Influence of age and hematocrit on the coagulation of blood

To examine the effects of age, hematocrit and the daily variation in hematocrit on coagulation of blood, the time of onset of coagulation (Ti) of whole blood obtained from donors including normal subjects and patients was measured by means of a rheological technique. The Ti value of recalcified blood decreased with an increase in age, but in donors aged 65 years or more (the elderly), the Ti value was almost independent of age. The Ti value for blood obtained from the elderly was significantly lower at lower hematocrit levels, but that for blood obtained from young donors was almost independent of hematocrit. The daily variation in hematocrit in individuals was small (maximum variation: about 4%), and the variation had little effect on the Ti value. However, a slight increase in hematocrit was considered to bring about a significant increase in viscosity at lower shear rates. Therefore, it is suggested that a slight increase in hematocrit under stagnant flow conditions is one of major risk factors for venous thrombogenesis, especially in the elderly.     

Gnawing bones as enrichment for farmed blue foxes ( Vulpes lagopus)

According to present acts and regulations, farmed foxes shall have a gnawing or other enrichment object in their cages. However, research on the welfare effects of gnawing objects has been scarce. We assessed physiology and health, that is weight development, urinary cortisol-creatinine ratio, serum cortisol level after adrenocorticotropic hormone administration, internal organ masses and incidence of gastric ulcerations as well as dental and overall oral health, in pair-housed juvenile blue foxes that were housed either with or without a possibility to interact with bones (cattle femur) during their growing season (July to December). The results show that the physiological effects of the possibility to interact with bones were either non-significant or suggested that competition for bones may jeopardize the welfare of subordinate individuals. However, the results clearly show that gnawing bones are beneficial for the dental health of farmed foxes.     

Regulation of energy economy in raccoon dogs and blue foxes: a process of dynamic interactions

1. Seasonal regulation of energy economy was studied in farm-raised blue foxes (Alopex lagopus) and raccoon dogs (Nyctereutes procyonoides; Gray, 1834). 2. Both species exhibited marked seasonal changes in body weight, body energy content, food intake and locomotor activity. Seasonal changes in food efficiency were also evident. 3. The results emphasize the important role of both energy intake and energy expenditure in the regulation process. 4. It can be concluded that regulation of seasonal energy balance is a dynamic process with various interactions between different factors.     

Physiological adaptations to fasting in an actively wintering canid, the Arctic blue fox (Alopex lagopus)

This study investigated the physiological adaptations to fasting using the farmed blue fox (Alopex lagopus) as a model for the endangered wild arctic fox. Sixteen blue foxes were fed throughout the winter and 32 blue foxes were fasted for 22 d in Nov-Dec 2002. Half of the fasted blue foxes were food-deprived again for 22 d in Jan-Feb 2003. The farmed blue fox lost weight at a slower rate (0.97-1.02% body mass d(-1)) than observed previously in the arctic fox, possibly due to its higher initial body fat content. The animals experienced occasional fasting-induced hypoglycaemia, but their locomotor activity was not affected. The plasma triacylglycerol and glycerol concentrations were elevated during phase II of fasting indicating stimulated lipolysis, probably induced by the high growth hormone concentrations. The total cholesterol, HDL- and LDL-cholesterol, urea, uric acid and total protein levels and the urea:creatinine ratio decreased during fasting. Although the plasma levels of some essential amino acids increased, the blue foxes did not enter phase III of starvation characterized by stimulated proteolysis during either of the 22-d fasting procedures. Instead of excessive protein catabolism, it is liver dysfunction, indicated by the increased plasma bilirubin levels and alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase activities, that may limit the duration of fasting in the species.     

Plasma marking of arctic foxes with iophenoxic acid

Six arctic foxes (Alopex lagopus) were marked with iophenoxic acid (IA), a substance which elevates concentrations of protein-bound iodine in blood plasma. Buccal absorption of IA was determined by placing 20 mg IA dissolved in 100% ethyl alcohol on the tongue. Blood samples collected from 1 to 36 wk following exposure showed that all foxes were marked already at 1 wk and continued until 13 wk; two foxes were still marked at 36 wk. Clearance rates for iodine varied with initial dose response, and those foxes with high 1-wk iodine concentrations excreted iodine more rapidly than those with lower initial concentrations; by 13-wk excretion rates were similar.     

Novel microbiological system for antibiotic detection in ovine milk

This article presents a microbiological system composed of a “BT” bioassay (Beta-lactams and Tetracyclines) and a “QS” bioassay (Quinolones and Sulfonamides). The “BT” bioassay contains spores of Geobacillus stearothermophilus, bromocresol purple and cloramphenicol in a culture medium (incubation time: 2.45 h), while the “QS” bioassay uses spores of Bacillus subtilis, trifenyltetrazolium – toluidine blue and trimethoprim in a suitable culture medium (incubation time: 5.5 h). The detection capability (CC_β) of 27 antimicrobial agents in ovine milk were determined by logistic regression models. Thus, the “BT” bioassay detects amoxycillin, ampicillin, penicillin “G”, cloxacillin, oxacillin, cephalexin, cefoperazone, ceftiofur, chlortetracycline, oxytetracycline, tetracycline, neomycin, gentamycin and tylosin, while “QS” bioassay detects: ciprofloxacin, enrofloxacin, marbofloxacin, sulfadiazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfamethoxazole, sulfathiazole, erythromycin, lincomycin and spiramycin at levels close to their respective Maximum Residue Limits. The simultaneous use of both bioassays detects a large number of antibiotics in milk given each method's adequate complementary sensitivity.     

Flavonoid compounds related to seed coat color of wheat

In red wheat, reddish-brown pigments accumulate in testa of mature seeds. Half-cut wheat seeds were immersed in p-dimethylaminocinnamaldehyde (DMACA) reagent that stains flavanol structures blue. Testa of 10–40 days after flowering (DAF) in red wheat (“Norin 61” and “Satonosora”) seeds were stained blue and the reagent color changed to blue with 10–25 DAF seeds. No blue staining was observed in white wheat (“Tamaizumi”) seeds during maturation. “Norin 61” seed coats at 10 DAF contained dihydroquercetin, dihydromyricetin, (+)-catechin, procyanidin B3, and prodelphinidin B3, which were identified by HPLC-diode array detector and LC-MS/MS analyses. These five components began accumulating 7 DAF, reached maxima at 10 or 15 DAF, and then decreased in red wheat seeds, but were not detected in white wheat seeds. These results suggest that flavanol and proanthocyanidins are possible precursors of the reddish-brown pigments of red wheat seeds, and are converted to insoluble compounds as the seeds mature.     

Structure of arctic fox (Alopex lagopus beringensis) colonies in the northern extremity of Bering Island

Data on the spatial structure of an Arctic fox (Alopex lagopus beringensis) colony were obtained in July-August 1995, using walk counts and observations near living dens around the Northern rookery of the northern fur seals located on Bering Island (Commander Islands). The home ranges of 31 Arctic fox families (61 adults and 145 pups inhabiting 66 dens) were found over 27 km of the coastline. Sixty individuals (3 adults and 57 pups) were marked by color ear-tags. Among adult foxes, 24 (39.3%) were recognized as females and 12 (19.7%) as males; the sex of 25 (41.0%) foxes was not recognized. Among 57 marked cubs, 26 (45.6%) were females and 31 (54.4%) were males. The best studied families (13) had 3–11 pups (6.7 ± 0.7, on average). The survival of cubs at an age younger than 2.0–2.5 months was 82.5%; 30.8% of the families consisted of more than two adults. The distribution of the Arctic fox dens and home ranges along the coastline has been studied; specific features of the location of dens have been described. In the studied area, Arctic foxes have been foraging on birds (67.6% of dens with food remains), northern fur seals (40.5), other marine mammals (13.5), Pacific salmon (29.7), and reindeer (2.7%), as well as on amphipods and voles. Rich constant food sources (rookeries, marine bird colonies, and spawning places of the blueback salmon) were found in 7 home ranges of the Arctic fox; 6 home ranges included temporary food sources (spawning streams of the humpback salmon); and 18 home ranges were poor in food resources. Arctic foxes whose home ranges lie within 6–7 km around a “food patch” used the concentrated food resources together. Food resources are supposed to become important only after the raised pups turn to self-feeding. Differences in the use of space, foraging and breeding of the two Arctic fox subspecies (A. l. beringensis and A. l. semenovi), and arrangement of colonies around the northern fur seal rookeries are discussed.     

Adrenocortical steroid hormones in production of hypertension in sheep

In the conscious sheep the contribution of physiological and pharmacological levels of the two major classes of adrenal steroid hormones “glucocorticoids” and “mineralocorticoids” in the production of hypertension have been examined using the model of ACTH induced hypertension, an adrenally dependent steroid hypertension which can be reproduced by infusion over 5 days of a combination of cortisol (5 mg/h), corticosterone (0.5mg/h), 11-deoxycortisol (1 mg/h), DOC (25 mg/h), aldosterone (3μg/h), 17α-hydroxyprogesterone (1 mg/h) and 17α,20α-dihydroxyprogesterone (500 μg/h) at rates to produce blood levels seen with ACTH treatment. Hypertension cannot be reproduced by infusion of any of these steroids individually at these rates. Omission of 17α-hydroxyprogesterone and 17α,20α-dihyroxyprogesterone from the infusion results in similar metabolic effects to ACTH but only small increases in blood pressure. These studies together with in vitro and in vivo assessment of the lack of “mineralocorticoid” and “glucocorticoid” activity of 17α-hydroxyprogesterone and 17α,20α-dihydroxy-progesterone have led us to postulate a new class of steroid action—hypertensinogenic steroids. Infusion of 9α-fluorocortisol (9α-FF) at 0.2 mg/day increases blood pressure without the associated metabolic effects seen at higher dose (0.63 or 2 mg/day). Based on in vitro renal receptor affinity of 9α-FF for “mineralocorticoid” and “glucocorticoid” receptors, doses of aldosterone and cortisol approx. equivalent to either 0.63 or 2 mg/day of 9α-FF reproduce the metabolic effects of 9α-FF but have only a small effect on blood pressure. These data suggest that the hypertensive effects of adrenal steroid hormones are not simply related to their “mineralocorticoid” or “glucocorticoid” activity and support our proposal of a further class of steroid hormone action.     

Complex housing environment for farmed blue foxes (Vulpes lagopus): use of various resources

The present study was designed to measure the use of various, simultaneously available resources in a complex housing environment in juvenile blue foxes. Twelve blue fox sibling (male–female) pairs were housed in two-section experimental cages from the age of 8 weeks until the age of 7 months (from June to December). Each experimental cage was furnished with two platforms, a nest box, a sand box and a wooden block. This housing set-up provided the foxes with social contact, and an opportunity for oral manipulation, scratching and nesting, as well as the choice of staying on a solid floor material or on an elevated location. The foxes’ behaviour was recorded at three time points during autumn (September, November and December). The foxes used all available resources. The most utilised resource was the nest box, possibly because it could be utilised in several ways (as a shelter, an elevated location, an object for scratching and for oral manipulation). The foxes also stayed more in the cage section containing the nest box than in the cage section containing a sand box. The foxes rested much on the cage floor, but they also used the interior of the nest box and elevated locations for resting. Social contact often occurred during resting. Thus, the nest box and elevated location, in conjunction with social contact seem to be valuable while resting. While active, the foxes utilised the cage floor and roof of the nest box instead of the platforms. Scratching, digging and an interaction with the wooden block were seldom observed. Activity occurred mainly on the ‘empty’ cage area. In conclusion, all studied resources provided blue foxes with a distinct value, as they all were used in the complex housing environment. The nest box is used most and for most variable behaviours.     

Position of operant cost affects blue foxes’ time budget between sand floor and mesh floor

The aim of the study was to assess whether positioning of the operant cost would affect blue foxes’ (Vulpes lagopus) behaviour and time budget between a mesh floor and sand floor. We built fourteen test apparatuses, six consisting of two fox cages with a mesh floor in both cages and eight with a mesh floor in one cage and a sand floor in the other cage. A cost could be imposed to pass through one-way doors between the cages. The effect of changing the cost to move from the mesh floor to the sand floor or from the sand floor to the mesh floor or between the two mesh floors was examined in 28 juvenile male blue foxes. The foxes’ time allocation between the cages was recorded for four different costs. The foxes’ behaviour was analysed in more detail at the lowest and highest costs. The visit duration increased considerably when leaving the cage became costly, but did not markedly change when entering was costly. The foxes spent less time on the sand floor than on the mesh floor. The foxes preferred to rest on the mesh floor, but rested also on the sand floor when there was a cost associated with leaving the sand floor. The sand floor stimulated digging, rooting and play. In conclusion, both positioning of the cost and the floor material affected blue foxes’ time budget between the two cages.     

Extent of digging and its possible underlying causal factors in penned blue foxes

A recent European animal welfare recommendation stresses the importance of studying digging behaviour in farm-born blue foxes (Alopex lagopus). The current study was conducted (1) to clarify the extent of digging and (2) to evaluate factors that motivate digging. In experiment 1, six juvenile male blue foxes were housed together from August to the following June in an earthen enclosure. Experiment 2 was conducted from July to December, using ten enclosures each containing two juvenile male blue foxes. Behaviour was monitored by 24-h video recordings and visual observations. Progress of digging was also followed by making scale drawings of all digging marks on paper. As early as the first study day, clear signs of digging were observed. Digging sites were concentrated below and close to nestboxes and pen walls. Maximally about 20% of the total enclosure area was affected. The total surface area of digging sites did not increase from late summer onwards because foxes tended simultaneously to cover part of the old sites when digging new ones. Motivational tendency to dig varied with time. Digging activity decreased during autumn and almost totally ceased during winter. In May, foxes resumed digging activity. Digging motivation was evaluated by two means: (1) by analyzing digging purpose (experiments 1 and 2), and (2) by the damming-up test (experiment 1), that is, after 10 months foxes that had been exposed to the earthen floor were transferred for 12 days into wire-mesh cages with no possibility to dig in the ground. Thereafter, foxes were transferred back into the earthen enclosure to measure the rebound of digging following deprivation. Foxes were observed to dig for the following reasons: (1) to make a hole or a resting site, (2) to locate an escape route, (3) to cache food, faeces, or sticks, (4) in response to a novel object (new nestbox, replacement of nestbox), and (5) displacement without any clear goal. Daily time spent digging averaged 7 min and 17 min per fox in Exps. 1 and 2, respectively. A clear rebound effect for digging was not identified. It can be concluded that digging is a complex behavioural pattern caused by a variety of motivations that can vary over time. The present study was unable to show unambiguously that digging is an important need for farmed foxes. Received: 28 February 2000 / Received in revised form: 6 June 2000 / Accepted: 20 June 2000     

花生对镉胁迫的生理响应及品种间差异

深入研究花生镉毒害机理对于筛选和利用抗镉污染花生种质资源具有重要的理论和实际意义.本文以14个花生品种为材料,以花期花生功能叶叶绿素含量、根系和叶片丙二醛含量、细胞膜透性和根系氧化活力等生理参数为指标,利用人工气候箱砂培试验,研究了6种Cd浓度胁迫下花生植株的生理毒害反应及其品种间遗传差异.结果表明: 在0～60 mg Cd ·L^-1范围内,随着营养液添加Cd浓度的增加,花生叶绿素含量和根氧化活力极显著降低,根、叶细胞膜透性和根、叶丙二醛含量极显著增加,且品种与Cd浓度间具有显著交互作用; 花生根、叶细胞膜透性是对镉胁迫响应最为敏感的生理参数,而叶绿素含量对镉胁迫响应相对不敏感; 各生理参数与营养液Cd浓度关系的线性回归方程的斜率(b)与截距(a)之比值的绝对值︱b/a︱能够较好地描述不同花生品种对镉胁迫的敏感性.对6个生理参数的︱b/a︱值进行综合赋值及敏感性五级聚类分析得知,在供试花生品种中,“中花4号”、“湘农55号”和“湘农3010-w”等3个品种对镉反应高度敏感(Ⅰ级);“莱农29”、“湘农小果w2-7”、“丰花2号”、“莱农13”、“豫花15号”和“丰花3号”等6个品种反应敏感(Ⅱ级);“湘农312”、“祁阳小籽”和“平度01”等3个品种反应一般(Ⅲ级);“花育23 ”和“花育20”等两个品种反应钝感(Ⅳ级).