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Lewejohann, Lars, Kerstin Schwabe, Christine Häger und Paulin Jirkof. „Impulse for animal welfare outside the experiment“. Laboratory Animals 54, Nr. 2 (12.02.2020): 150–58. http://dx.doi.org/10.1177/0023677219891754.
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Animal welfare is a growing societal concern and the well-being of animals used for experimental purposes is under particular scrutiny. The vast majority of laboratory animals are mice living in small cages that do not offer very much variety. Moreover, the experimental procedure often takes very little time compared to the time these animals have been bred to the desired age or are being held available for animal experimentation. However, for the assessment of animal welfare, the time spent waiting for an experiment or the time spent after finishing an experiment has also to be taken into account. In addition to experimental animals, many additional animals (e.g. for breeding and maintenance of genetic lines, surplus animals) are related to animal experimentation and usually face similar living conditions. Therefore, in terms of improving the overall welfare of laboratory animals, there is not only a need for refinement of experimental conditions but especially for improving living conditions outside the experiment. The improvement of animal welfare thus depends to a large extent on the housing and maintenance conditions of all animals related to experimentation. Given the current state of animal welfare research there is indeed a great potential for improving the overall welfare of laboratory animals.
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Popa, V. I., I. Lascar, M. Valcu, Ioana Teona Sebe, B. Caraban und Arina Cristiana Margina. „Bioethics in animal experimentation“. ARS Medica Tomitana 21, Nr. 4 (01.11.2015): 169–77. http://dx.doi.org/10.1515/arsm-2015-0041.
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Abstract Animal experiments are used on a large scale worldwide in order to develop or to refine new medicines, medicinal products or surgical procedures. It is morally wrong to cause animals to suffer, this is why animal experimentation causes serious moral problems. We must realize that we have moral and legal obligations when dealing with animals in our care, and this should become our high priority before any experiment. We have to take responsibility for the life of the animals and we have to act honorably regarding this issue because we have been given a trust by society in general which is not to be taken lightly. There is an ongoing societal debate about ethical issues of animal use in science. This paper is addressed to current and future researchers and is an appeal for them to (re)consider their personal views concerning the issue under scrutiny and their responsibility in ensuring that results would make the sacrifice worthwhile.
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Oliverius, Martin, Dušan Král, Eva Honsová, Alena Lodererová, Michal Kudla, Petr Baláž, Alexandros Valsamis und Jiří Čáp. „Surgical Technique of Small Bowel Transplantation in a Large Animal Model“. Acta Veterinaria Brno 79, Nr. 2 (2010): 281–87. http://dx.doi.org/10.2754/avb201079020281.
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An experiment was carried out on pigs during preparation of a clinical project of intestinal transplantation. The objective of this study was to find the best surgical technique of vascular and intestinal anastomosis in different experimental settings (animals with and without immunosuppression) which could have a major impact on everyday veterinary practice. Transplantation was performed in 43 pigs. In the surgical part of the experiment we examined the most suitable surgical technique of vascular anastomosis. A running continuous single-layer seromuscular suture was used for all types of intestinal anastomoses. With regard to vascular anastomosis, the animals were divided into two groups. In group 1 (n = 18) one animal was both donor and recipient of the intestinal graft. Anastomoses were constructed to the mesenteric vessel bed. In group 2 (n = 25), one animal was the graft donor and another was the graft recipient, with revascularization to the central vessel bed. In the second part of the study, we examined the impact of immunosuppressive drug administration on acute cellular rejection and animal survival. Animals that died due to technical failure and reasons unrelated to transplantation were excluded from the evaluation (19 pigs). A total of 24 pigs were included in the second part of the study. The animals were divided into four experimental groups. Group A - autotransplantation (n = 3), group B - allotransplantation on tacrolimus monotherapy (n = 7), group C on combined immunosuppression with tacrolimus and sirolimus (n = 8), and control group D - without immunosuppression (n = 6). Results: A high rate of vascular complications occurred in the first group; 67% (12 out of 18). In the second group, the rate of complications was reduced to 12% (3 out of 25). In the second part of the study the shortest survival was found in group D and the longest in group A. In neither of the immunosuppressed groups (B + C) did we find any significant difference in survival. No complication with the healing of intestinal anastomosis was found in any group. In conclusion we can state the single-layer continuous running suture was safe for all kinds of intestinal anastomoses. Vascular reconstruction to the central vessels was safer for graft survival.
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Festing, Michael F. W. „Reduction of animal use: experimental design and quality of experiments“. Laboratory Animals 28, Nr. 3 (01.07.1994): 212–21. http://dx.doi.org/10.1258/002367794780681697.
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Poorly designed and analysed experiments can lead to a waste of scientific resources, and may even reach the wrong conclusions. Surveys of published papers by a number of authors have shown that many experiments are poorly analysed statistically, and one survey suggested that about a third of experiments may be unnecessarily large. Few toxicologists attempted to control variability using blocking or covariance analysis. In this study experimental design and statistical methods in 3 papers published in toxicological journals were used as case studies and were examined in detail. The first used dogs to study the effects of ethanol on blood and hepatic parameters following chronic alcohol consumption in a 2 × 4 factorial experimental design. However, the authors used mongrel dogs of both sexes and different ages with a wide range of body weights without any attempt to control the variation. They had also attempted to analyse a factorial design using Student's t-test rather than the analysis of variance. Means of 2 blood parameters presented with one decimal place had apparently been rounded to the nearest 5 units. It is suggested that this experiment could equally well have been done in 3 blocks using 24 instead of 46 dogs. The second case study was an investigation of the response of 2 strains of mice to a toxic agent causing bladder injury. The first experiment involved 40 treatment combinations (2 strains × 4 doses × 5 days) with 3-6 mice per combination. There was no explanation of how the experiment involving approximately 180 mice had actually been done, but unequal subclass numbers suggest that the experiment may have been done on an ad hoc basis rather than being properly designed. It is suggested that the experiment could have been done as 2 blocks involving 80 instead of about 180 mice. The third study again involved a factorial design with 4 dose levels of a compound and 2 sexes, with a total of 80 mice. Open field behaviour was examined. The author incorrectly used the t-test to analyse the data, and concluded that there was no dose effect, when a correct analysis showed this to be highly significant. In all case studies the scientists presented means α standard deviations or standard errors involving only the animals contributing to that mean, rather than the much better estimates that would be obtained with a pooled estimate of error. This is virtually a universal practice. While it is not in itself a serious error, it may lead scientists to design experiments with group sizes of at least 3 animals, which may result in an unnecessarily large experiment if there are many treatment combinations. In conclusion, all 3 papers could have been substantially improved, with higher precision and the use of fewer animals if more attention had been paid to better experimental design.
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Ranc, Nathan, Paul R. Moorcroft, Federico Ossi und Francesca Cagnacci. „Experimental evidence of memory-based foraging decisions in a large wild mammal“. Proceedings of the National Academy of Sciences 118, Nr. 15 (09.04.2021): e2014856118. http://dx.doi.org/10.1073/pnas.2014856118.
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Many animals restrict their movements to a characteristic home range. This constrained pattern of space use is thought to result from the foraging benefits of memorizing the locations and quality of heterogeneously distributed resources. However, due to the confounding effects of sensory perception, the role of memory in home-range movement behavior lacks definitive evidence in the wild. Here, we analyze the foraging decisions of a large mammal during a field resource manipulation experiment designed to disentangle the effects of memory and perception. We parametrize a mechanistic model of spatial transitions using experimental data to quantify the cognitive processes underlying animal foraging behavior and to predict how individuals respond to resource heterogeneity in space and time. We demonstrate that roe deer (Capreolus capreolus) rely on memory, not perception, to track the spatiotemporal dynamics of resources within their home range. Roe deer foraging decisions were primarily based on recent experience (half-lives of 0.9 and 5.6 d for attribute and spatial memory, respectively), enabling them to adapt to sudden changes in resource availability. The proposed memory-based model was able to both quantify the cognitive processes underlying roe deer behavior and accurately predict how they shifted resource use during the experiment. Our study highlights the fact that animal foraging decisions are based on incomplete information on the locations of available resources, a factor that is critical to developing accurate predictions of animal spatial behavior but is typically not accounted for in analyses of animal movement in the wild.
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Eldridge, GA, CG Winfield und DJ Cahill. „Responses of cattle to different space allowances, pen sizes and road conditions during transport“. Australian Journal of Experimental Agriculture 28, Nr. 2 (1988): 155. http://dx.doi.org/10.1071/ea9880155.
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Angus x Shorthorn heifers weighing about 350 kg were used to study the responses of heart rate and behaviour to different pen sizes, space allowances and road conditions during transport. In experiment 1, 6 groups of 9 heifers were transported at contrasting space allowances (0.9 and 1.1 m2/animal) on two 135- km journeys over a predetermined route of country, highway and suburban roads. Space allowance was varied by adjusting pen size. In experiment 2,4 groups of 8 heifers were used in a 2 (space allowances [0.8 and 1.0 m2/animal])x2 (pen sizes [8 and 16 m2]) factorial experiment to determine animal responses during a 31 km journey over sealed suburban roads. Space allowance was adjusted by adding non-experimental animals from the same herd. In experiment 3,6 groups of 7 animals were used to study the response of cattle to 2 space allowances (0.89 and 1.14 mVanima1) during a journey of 424 km. Space allowance was adjusted by using non-experimental animals from the same herd. In all experiments, animals transported at the lower space allowances had 3.9-6.7% lower heart rates (P < 0.05) and l27-260% lower movement scores (P < 0.05) than did animals transported at higher space allowances. In experiment 1, road type significantly affected heart rate (P<0.05) but not movement. In experiment 2, both heart rate and movement were significantly (P<0.01) less in small pens compared with large pens (heart rate 68.8 v. 71.7 bpm; number of movements 7.1 v. 15.8). There was a significant (P<0.05) interaction between space allowance and pen size on heart rate, but not on the amount of movement. In experiment 3, the stage of the journey did not affect the difference in heart rate between space allowance treatments. It is concluded that, within the ranges of the variables examined, road transport was less demanding on cattle in small pens with a small space allowance. It is suggested that space allowances can be more readily manipulated in transport vehicles with small pens and so minimise risks to animal welfare during rapid changes in vehicle motion.
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Lee, Byunghun, und Yaoyao Jia. „Wirelessly-Powered Cage Designs for Supporting Long-Term Experiments on Small Freely Behaving Animals in a Large Experimental Arena“. Electronics 9, Nr. 12 (25.11.2020): 1999. http://dx.doi.org/10.3390/electronics9121999.
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In modern implantable medical devices (IMDs), wireless power transmission (WPT) between inside and outside of the animal body is essential to power the IMD. Unlike conventional WPT, which transmits the wireless power only between fixed Tx and Rx coils, the wirelessly-powered cage system can wirelessly power the IMD implanted in a small animal subject while the animal freely moves inside the cage during the experiment. A few wirelessly-powered cage systems have been developed to either directly power the IMD or recharge batteries during the experiment. Since these systems adapted different power carrier frequencies, coil configurations, subject tracking techniques, and wireless powered area, it is important for designers to select suitable wirelessly-powered cage designs, considering the practical limitations in wirelessly powering the IMD, such as power transfer efficiency (PTE), power delivered to load (PDL), closed-loop power control (CLPC), scalability, spatial/angular misalignment, near-field data telemetry, and safety issues against various perturbations during the longitudinal animal experiment. In this article, we review the trend of state-of-the-art wirelessly-powered cage designs and practical considerations of relevant technologies for various IMD applications.
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Gaponov, N. V., O. P. Neverova, O. V. Gorelik und A. V. Stepanov. „Probiotics and animal feed in primates feeding“. E3S Web of Conferences 222 (2020): 02006. http://dx.doi.org/10.1051/e3sconf/202022202006.
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This paper presents the results of experiments on primates feeding. In diet structures that were used animal feed, of which fish flour is the most valuable, as found, for monkeys, due to its unique chemical composition. And the effect of the probiotic complex “Bactistatin” on the digestibility of feed in the diet of rhesus monkeys was studied. This preparation belongs to the new generation of probiotics. It is a biological product with immobilized probiotic strains and their metabolites. The study was conducted on a large population of male rhesus macaques in enclosure conditions. Feeding diets, their nutritional value as a result of the inclusion of fish flour in the amount of 18% were studied. And also, the effect of “Bactistatin” in the amount of 3 g/head, on the formation of symbiotic microflora of the gastrointestinal tract, was studied in order to improve the absorption of nutrients in complete feed. Changes in homeostasis during the experiment were controlled by hematological and biochemical parameters of the blood of both experimental and control primates. At the end of the experiment, the cost of feed, nutrients, and exchange energy per head was calculated. The experimental data obtained were analyzed and mathematically processed.
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Tang, Qing Guo, Shang Yue Shen, Bao Xia Teng, Li Juan Wang und Fei Wang. „Effect of Large Dose of Attapulgite on Animal Growth and Blood Microenvironment“. Advanced Materials Research 96 (Januar 2010): 41–48. http://dx.doi.org/10.4028/www.scientific.net/amr.96.41.
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Effect of acute toxicity and chronic toxicity on attapulgite for animal was studied by Kunming mice and SD rats experiment through administering intragastrically with large dose of attapulgite suspension. The results showed that the mice were normal and grew well, and they did not appear death and toxicity symptoms when they received the same amount as 286 times of the adult dose, indicating that attapulgite mineral powders did not contain acute toxicity and administering intragastrically with large dose of attapulgite suspension had no obvious influence on blood environment and normal growth of rats, and attapulgite did not contain chronic toxicity.
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Hegel, U., M. Fromm, K. M. Kreusel und M. Wiederholt. „Bovine and porcine large intestine as model epithelia in a student lab course.“ Advances in Physiology Education 265, Nr. 6 (Dezember 1993): S10. http://dx.doi.org/10.1152/advances.1993.265.6.s10.
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A short-circuit current experiment on epithelial ion transport is described that is suitable for student classes in human and animal physiology. Segments of late distal colon from either pig or cow are obtained from the slaughterhouse depending on the animals' daily schedule. Initial tissue preparation already in the slaughterhouse, cold storage, and proper choice of bath solutions are essential prerequisites for success. Students monitor spontaneous transepithelial voltage and short-circuit current (Isc) by use of manually operated voltage clamp units. Two main transport mechanisms are studied, electrogenic Na+ absorption and Cl- secretion. Electrogenic Na+ absorption is studied by measuring the Isc drop after amiloride. Then Cl- secretion is stimulated by theophylline and subsequently inhibited by furosemide. In some experiments K+ secretion can be detected by the blocking effect of mucosal Ba2+. Response of tissues from pig and cow is qualitatively similar but quantitatively different. The equipment is sturdy and inexpensive, can be provided by most departmental workshops, and has been tested for 3 yr in regular lab courses. Observations made during these experiments are closely related to clinical states, such as secretory diarrhea, cystic fibrosis, and hyperaldosteronism, as well as to the mechanisms of clinically used diuretics.
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Lipatov, Vyacheslav A., Aleksey A. Kryukov, Dmitry A. Severinov und Araik R. Saakyan. „Ethical and legal aspects of in vivo experimental biomedical research“. I.P. Pavlov Russian Medical Biological Herald 27, Nr. 1 (02.04.2019): 80–92. http://dx.doi.org/10.23888/pavlovj201927180-92.
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In XXI century in vivo experiments came into a common use in connection with development of biological and medical scientific fields. In the first part of the work historical and techni-cal aspects of use of animals in in vivo experiments are considered. In the work the problem of choice of a kind of laboratory animal for experimental purposes is discussed, and also the number of animals in the experimental groups is substantiated for further statistical processing of the primary information and determination of the reliability of differences in interpretation of the obtained results. According to the data of analyzed literature sources, modern researchers keep to the non-violence strategy and ahimsa principle (from Lat. ahimsᾱ causing no harm). Here, the dominating point of view is the necessity for in vivo experiments for further development of the biomedical science. This is possible provided suffering of animals are minimized with their minimal number in an experiment. The choice of the animal species first of all depends on the task faced by an experimenter. Besides, in each research a thorough choice of a specific animal is required based on the information of its health, maintenance and feeding, anatomical and physiological peculiarities, age, genetic characteristics. Chronic and acute surgical experiments are usually conducted on large vertebrate animals: dogs, European rabbits, house cats, while the action and effectiveness of pharmacological drugs are more conveniently studied on small laboratory animals: house mice, common rats, guinea-pigs, golden hamsters.
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East, Barbora, Martin Plencner, Martin Kralovic, Michala Rampichova, Věra Sovkova, Karolína Vocetkova, Martin Otahal et al. „A polypropylene mesh modified with poly-ε-caprolactone nanofibers in hernia repair: large animal experiment“. International Journal of Nanomedicine Volume 13 (Mai 2018): 3129–43. http://dx.doi.org/10.2147/ijn.s159480.
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Han, Sung Joon, Woosik Han, Hee-Jung Song, Cuk-Seong Kim, Seong-Mok Jeong und Min Woong Kang. „Validation of Nafamostat Mesilate as an Anticoagulant in Extracorporeal Membrane Oxygenation: A Large-Animal Experiment“. Korean Journal of Thoracic and Cardiovascular Surgery 51, Nr. 2 (05.04.2018): 114–21. http://dx.doi.org/10.5090/kjtcs.2018.51.2.114.
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Dyer, John R. G., Anders Johansson, Dirk Helbing, Iain D. Couzin und Jens Krause. „Leadership, consensus decision making and collective behaviour in humans“. Philosophical Transactions of the Royal Society B: Biological Sciences 364, Nr. 1518 (12.12.2008): 781–89. http://dx.doi.org/10.1098/rstb.2008.0233.
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This paper reviews the literature on leadership in vertebrate groups, including recent work on human groups, before presenting the results of three new experiments looking at leadership and decision making in small and large human groups. In experiment 1, we find that both group size and the presence of uninformed individuals can affect the speed with which small human groups (eight people) decide between two opposing directional preferences and the likelihood of the group splitting. In experiment 2, we show that the spatial positioning of informed individuals within small human groups (10 people) can affect the speed and accuracy of group motion. We find that having a mixture of leaders positioned in the centre and on the edge of a group increases the speed and accuracy with which the group reaches their target. In experiment 3, we use large human crowds (100 and 200 people) to demonstrate that the trends observed from earlier work using small human groups can be applied to larger crowds. We find that only a small minority of informed individuals is needed to guide a large uninformed group. These studies build upon important theoretical and empirical work on leadership and decision making in animal groups.
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Quiniou, N., und J. Noblet. „The effect of energy supply on the contribution of lean tissue to total body protein mass in pigs slaughtered at 100 kg“. Animal Science 65, Nr. 3 (Dezember 1997): 509–13. http://dx.doi.org/10.1017/s1357729800008717.
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AbstractThe effect of energy supply between 45 and 100 kg body weight (BW) on the contribution of lean tissue (muscle plus intermuscular adipose tissue) to total protein mass was studied in Large White castrated males (cLW), crossbred Piétrain × Large White castrated males (cPPx) and boars (bPPx). The pigs were allocated to four energy levels (0·70, 0·80, 0·90 or 1·00 ad libitum) and kept in metabolism cages in experiment 1 or given food ad libitum and kept in individual pens in experiment 2. Daily protein supplies were calculated to be non-limiting for growth and identical for all pigs in experiment 1. Temperature was 23°C in both experiments. The pigs were slaughtered at 100 kg BW and physically dissected; the body tissues were chemically analysed. Taking into account housing conditions, the food intake of pigs in experiment 2 corresponded to 1·20 of ad libitum intake of pigs in experiment 1; data of both experiments were combined. The energy supply and the type of pig influenced significantly the protein content of empty BW (eBW) (170 g/kg on average), of lean (184g/kg on average) and non-lean compartment (eBW minus lean, 152 g/kg on average), the proportion of total protein deposited in lean (604 g/kg of total protein, on average) but not the protein content in fat-free eBW (209 g/kg on average). The fat-free eBW can be predicted as 4·8 times the body protein mass.
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Lazic, Stanley E. „Four simple ways to increase power without increasing the sample size“. Laboratory Animals 52, Nr. 6 (08.04.2018): 621–29. http://dx.doi.org/10.1177/0023677218767478.
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Underpowered experiments have three problems: true effects are harder to detect, the true effects that are detected tend to have inflated effect sizes and as power decreases so does the probability that a statistically significant result represents a true effect. Many biology experiments are underpowered and recent calls to change the traditional 0.05 significance threshold to a more stringent value of 0.005 will further reduce the power of the average experiment. Increasing power by increasing the sample size is often the only option considered, but more samples increases costs, makes the experiment harder to conduct and is contrary to the 3Rs principles for animal research. We show how the design of an experiment and some analytical decisions can have a surprisingly large effect on power.
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ATWAL, A. S., L. C. HESLOP und K. LIEVERS. „EFFECTIVENESS OF ANHYDROUS AMMONIA AS A PRESERVATIVE FOR HIGH-MOISTURE ALFALFA HAY IN LARGE ROUND BALES“. Canadian Journal of Animal Science 66, Nr. 3 (01.09.1986): 743–53. http://dx.doi.org/10.4141/cjas86-081.
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Two experiments were conducted in sequence to determine the effectiveness of anhydrous ammonia (AA) as a preservative of alfalfa hay stored as large round bales (LRB). In the the first experiment application of 3% AA (wt/wt) to alfalfa hay baled at about 23% moisture-content (MC) increased the temperature markedly above the control treatment and resulted in a significantly (P < 0.05) higher acid-detergent-insoluble nitrogen and acid-detergent lignin. In the second experiment application of about 1% AA slowly (over 48 h) to LRB of alfalfa hay packaged at about 30% and > 35% MC, significantly (P < 0.05) reduced the cumulative degree-days above all reference points from 35 to 65 °C. Ammoniation completely eliminated dry matter losses in storage which were highest (8.3%) for 33% MC control hay. High moisture control hay (33% MC) suffered severe heat damage with 33% of total N being in the acid-detergent-insoluble fraction as compared to less than 10% for medium-moisture (26% MC) control and even lower values for ammoniated hay. Digestibility of crude protein and energy was significantly (P < 0.05) improved by ammoniation of medium-moisture (about 30% in-to-storage) alfalfa hay. When the ammonia-treated hay was uncovered in spring, coarsely ground and stored in a hay wagon the high-moisture-ammoniated hay (> 35% MC) became moldy within 4 wk, even when the ambient temperature was about 6 °C, whereas medium-moisture-ammoniated hay (about 30% MC) showed some deterioration after 7 wk as the ambient temperature increased to about 12 °C. Key words: Ammonia, alfalfa hay, digestibility, heat damage, high-moisture hay, large bales
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Rousselet, Guillaume A., Marc J. M. Macé, Simon J. Thorpe und Michéle Fabre-Thorpe. „Limits of Event-related Potential Differences in Tracking Object Processing Speed“. Journal of Cognitive Neuroscience 19, Nr. 8 (August 2007): 1241–58. http://dx.doi.org/10.1162/jocn.2007.19.8.1241.
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We report results from two experiments in which subjects had to categorize briefly presented upright or inverted natural scenes. In the first experiment, subjects decided whether images contained animals or human faces presented at different scales. Behavioral results showed virtually identical processing speed between the two categories and very limited effects of inversion. One type of event-related potential (ERP) comparison, potentially capturing low-level physical differences, showed large effects with onsets at about 150 msec in the animal task. However, in the human face task, those differences started as early as 100 msec. In the second experiment, subjects responded to close-up views of animal faces or human faces in an attempt to limit physical differences between image sets. This manipulation almost completely eliminated small differences before 100 msec in both tasks. But again, despite very similar behavioral performances and short reaction times in both tasks, human faces were associated with earlier ERP differences compared with animal faces. Finally, in both experiments, as an alternative way to determine processing speed, we compared the ERP with the same images when seen as targets and nontargets in different tasks. Surprisingly, all task-dependent ERP differences had relatively long latencies. We conclude that task-dependent ERP differences fail to capture object processing speed, at least for some categories like faces. We discuss models of object processing that might explain our results, as well as alternative approaches.
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Purchas, R. W. „Opportunities and challenges in meat production from sheep“. Australian Journal of Experimental Agriculture 47, Nr. 10 (2007): 1239. http://dx.doi.org/10.1071/ea07178.
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In response to a request for a viewpoint paper to be included in this Special Issue of the Australian Journal of Experimental Agriculture, this paper considers several aspects of meat production from sheep, some of which received particular attention in the two large-scale experiments described in papers in this Issue. Large experiments such as these, when combined with the involvement of diverse groups of scientists with complementary areas of interest and expertise, have enabled many aspects of the overall topic of sheep meat production to be investigated simultaneously. As a result, interrelationships between numerous characteristics of lambs and hoggets have been evaluated within a range of genotypes both within and between breeds and at several ages. This paper focuses on the nature of some relationships between growth characteristics and meat quality, the advantages and possible disadvantages of having large numbers of animals in an experiment and the apparently anomalous nature of information available on the effects of animal age on the tenderness of meat from lambs and sheep.
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Palek, R., A. Jonasova, J. Rosendorf, P. Mik, K. Bajcurova, P. Hosek, V. Moulisova et al. „Allogeneic venous grafts used for portal vein reconstruction after pancreaticoduodenectomy - large animal experiment and biomechanical study“. HPB 22 (2020): S245—S246. http://dx.doi.org/10.1016/j.hpb.2020.04.117.
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Mathis, Alicia. „Territoriality in a Terrestrial Salamander: the Influence of Resource Quality and Body Size“. Behaviour 112, Nr. 3-4 (1990): 162–75. http://dx.doi.org/10.1163/156853990x00176.
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AbstractIntraspecific interference competition associated with territoriality has been documented in laboratory studies of the red-backed salamander, Plethodon cinereus. I used laboratory and field experiments to study the effect of resource quality and body size on such competition. In an experiment in southwestern Virginia, cover objects (e.g., logs) from which the resident salamanders were removed were invaded significantly more often than cover objects from which the resident salamander was not removed. These data provide the first direct test of territoriality for a salamander in a natural habitat. Newly invading salamanders were significantly smaller than the original territorial residents. Therefore, large body size is an advantage in territorial encounters. Because cover objects are important resources for terrestrial salamanders, characteristics of the cover object may contribute to territory quality. In an experiment conducted during warm summer weather at the Virginia site, soil temperatures under large cover objects were significantly cooler than those under small cover objects or under the leaf litter. Large cover objects may therefore benefit the salamanders by providing a buffer zone between the salamander and extreme environmental temperatures on the forest floor. In both laboratory and field experiments, when salamanders were offered a choice between large and small cover objects, both large and small salamanders exhibited a significant preference for large cover objects. Also I censused cover objects in a natural mixed hardwood forest habitat during courting and noncourting seasons and, for both seasons, I found a significant positive correlation between the body size of the salamander and the size of the cover object that it occupied. I conclude that, in this natural forest habitat, there is intraspecific competition for high quality cover objects and larger individuals are more successful competitors than smaller individuals.
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Peters, I. O. M., A. Willemsen, J. J. de Bruyne und R. C. Nap. „Aspirin Medication in Dogs“. Veterinary and Comparative Orthopaedics and Traumatology 4, Nr. 03 (1991): 95–99. http://dx.doi.org/10.1055/s-0038-1633260.
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SummaryAspirin (acetylsalicylic acid; ASA) is widely used in both human and veterinary medicine. Therapeutic plasma salicylate concentrations (PSCs) can be reached using enteric-coated ASA tablets, but a delay in the initial rise and large fluctuations in the PSCs have been reported. From experiments described previously, the authors concluded that the large type enteric-coated ASA tablets were not suitable for use in beagle dogs.In the first experiment described here, these large type tablets were administered to large mongrel dogs. Although the mean PSC reached therapeutic levels after 44 h, in individual dogs subtherapeutic concentrations were frequently recorded. In the second experiment microgranulated type enteric-coated ASA tablets were given to beagle dogs in a crossover design study. PSCs in all dogs exceeded minimal therapeutic levels 6 h after tablet administration. Stable therapeutic PSCs were found in both groups on different feeding regimens. In the third experiment the two types of enteric-coated ASA tablets were administered to fasting beagles. Comparable therapeutic PSCs were reached with both formulations.From the present studies it can be concluded that the large type enteric-coated ASA tablet is not suitable for use in large mongrel dogs. Secondly, it can be concluded that the microgranulated type enteric-coated ASA tablet is suitable for the use in beagle dogs. In the third experiment it was proven that fasting eliminated the differences in mean PSC curves between the two types of ASA medication.On the basis of canine gastric physiology the authors expect similar types of large enteric-coated tablets of other drugs to generate comparably poor plasma concentrations. The gastric evacuation of tablets is primarily related to the tablet dimensions and digestibility, and not to the drug contained by these tablets.
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Hoareau, Guillaume L., Carl A. Beyer, Connor A. Caples, Marguerite W. Spruce, J. Kevin Grayson, Lucas P. Neff, Timothy K. Williams und M. Austin Johnson. „Automated Partial Versus Complete Resuscitative Endovascular Balloon Occlusion of the Aorta for the Management of Hemorrhagic Shock in a Pig Model of Polytrauma: a Randomized Controlled Pilot Study“. Military Medicine 185, Nr. 11-12 (01.11.2020): e1923-e1930. http://dx.doi.org/10.1093/milmed/usaa217.
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Abstract Introduction Endovascular variable aortic control (EVAC) is an automated partial resuscitative endovascular balloon occlusion of the aorta (REBOA) platform designed to mitigate the deleterious effects of complete REBOA. Long-term experiments are needed to assess potential benefits. The feasibility of a 24-hour experiment in a complex large animal trauma model remains unknown. Materials and methods Anesthetized swine were subjected to controlled hemorrhage, blunt thoracic trauma, and tibial fractures. Animals were then randomized (N = 3/group) to control (No balloon support), 90 minutes of complete supraceliac REBOA, or 10 minutes of supraceliac REBOA followed by 80 minutes of EVAC. One hundred ten minutes after injury, animals were resuscitated with shed blood, the REBOA catheter was removed. Automated critical care under general anesthesia was maintained for 24 hours. Results Animals in the control and EVAC groups survived to the end of the experiment. Animals in the REBOA group survived for 120, 130, and 660 minutes, respectively. Animals in the EVAC group displayed similar mean arterial pressure and plasma lactate concentration as the control group by the end of the experiment. Histologic analysis suggested myocardial injury in the REBOA group when compared with controls. Conclusions This study demonstrates the feasibility of intermediate-term experiments in a complex swine model of polytrauma with 90 minutes of REBOA. EVAC may be associated with improved survival at 24 hours when compared with complete REBOA. EVAC resulted in normalized physiology after 24 hours, suggesting that prolonged partial occlusion is possible. Longer studies evaluating partial REBOA strategies are needed.
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Freer, M., J. R. Donnelly, A. Axelsen, L. F. Myers, J. L. Davidson und J. Dymock. „Comparison of secale with other perennial grasses under grazing at a cool site in the high rainfall zone of New South Wales“. Australian Journal of Experimental Agriculture 37, Nr. 1 (1997): 19. http://dx.doi.org/10.1071/ea96062.
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Summary. In 2 field experiments on the southern highlands of New South Wales, the short-lived perennial grass secale (Secale montanum Guss. cv. Black Mountain) was grazed by Merino wether weaners at stocking rates of 10–17 animals/ha to test the suggestion that persistence might be enhanced by occasional deferment of grazing to encourage seedling germination. In the first of these experiments (experiment 1), designed to compare secale and phalaris, when accompanied by white and subterranean clovers, growth and survival of both grasses was poor, despite the application of >600 kg/ha superphosphate and the experiment was abandoned after 2 years. A subsequent pot trial (experiment 2) with secale grown in soil from the experimental site, where the fertiliser had been applied, showed a large growth response to additional phosphorus. Because inadequate soil fertility may have been the cause of poor grass persistence in experiment 1, a second field experiment (experiment 3) was established on the same site to compare secale, perennial ryegrass and cocksfoot, each accompanied by white and subterranean clovers and with the application of a further 850 kg/ha superphosphate over 3 years. Initial growth of all the grasses was good and animal production on the secale and ryegrass plots was high (up to 100 kg/ha greasy wool and 300 kg/ha liveweight gain). Secale failed to survive more than 3 years, despite deferment of grazing and it may be that persistence depends more on the reliability of autumn rainfall. However, mean weight gain from the clovers and volunteer grasses on the secale plots in the fourth year was as high as from the ryegrass plots and double that from the cocksfoot plots, which became increasingly cocksfoot-dominant. While the results indicate a need for more work on the fertiliser requirements of perennial grasses on these soils, they also raise questions about whether these grasses benefit animal production sufficiently to justify the cost of establishing them.
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Keenleyside, Miles H. A., Robert W. Rangeley und Bryan U. Kuppers. „Female mate choice and male parental defense behaviour in the cichlid fish Cichlasoma nigrofasciatum“. Canadian Journal of Zoology 63, Nr. 11 (01.11.1985): 2489–93. http://dx.doi.org/10.1139/z85-368.
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Female Cichlasoma nigrofasciatum presented with three potential spawning partners of different sizes spawned most often near the medium-sized male. When mate choice was restricted to males of two size classes, females consistently spawned near the larger male. In the former experiment, small males courted females more actively than medium or large males did. This may explain why females occasionally spawned near small males in both experiments. Larger brood-guarding males showed more intensive aggressive behaviour towards an adult conspecific confined near their offspring than did smaller brood-guarding males. Selection will therefore favour the female choice of relatively large mates because such males are likely to be more effective defenders of their offspring.
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Tillander, Matti, und Steffen Hokland. „Large volume 60 minute hyperthermia sonication with hilips Sonalleve V2 MR-HIFU System – animal in-vivo experiment“. Journal of Therapeutic Ultrasound 2, Suppl 1 (2014): A3. http://dx.doi.org/10.1186/2050-5736-2-s1-a3.
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Singulani, Junya L., Liliana Scorzoni, Haroldo C. de Oliveira, Caroline M. Marcos, Patricia A. Assato, Ana Fusco-Almeida und Maria Mendes-Giannini. „Applications of Invertebrate Animal Models to Dimorphic Fungal Infections“. Journal of Fungi 4, Nr. 4 (19.10.2018): 118. http://dx.doi.org/10.3390/jof4040118.
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Dimorphic fungi can be found in the yeast form during infection and as hyphae in the environment and are responsible for a large number of infections worldwide. Invertebrate animals have been shown to be convenient models in the study of fungal infections. These models have the advantages of being low cost, have no ethical issues, and an ease of experimentation, time-efficiency, and the possibility of using a large number of animals per experiment compared to mammalian models. Invertebrate animal models such as Galleria mellonella, Caenorhabditis elegans, and Acanthamoeba castellanii have been used to study dimorphic fungal infections in the context of virulence, innate immune response, and the efficacy and toxicity of antifungal agents. In this review, we first summarize the features of these models. In this aspect, the growth temperature, genome sequence, availability of different strains, and body characteristics should be considered in the model choice. Finally, we discuss the contribution and advances of these models, with respect to dimorphic fungi Paracoccidioides spp., Histoplasma capsulatum, Blastomyces dermatitidis, Sporothrix spp., and Talaromyces marneffei (Penicillium marneffei).
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Harkey, H. Louis, Ossama Al-Mefty, Isam Marawi, Dudley F. Peeler, Duane E. Haines und Lon F. Alexander. „Experimental chronic compressive cervical myelopathy: effects of decompression“. Journal of Neurosurgery 83, Nr. 2 (August 1995): 336–41. http://dx.doi.org/10.3171/jns.1995.83.2.0336.
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✓ Twelve dogs developed a delayed onset of neurological abnormalities from chronic cervical cord compression that was characteristic of myelopathy. The animals were divided into two groups and matched according to degree of neurological deficit. Six animals underwent decompression through removal of the anteriorly placed compressive device. Throughout the experiment, serial neurological examinations and somatosensory evoked potential studies were performed on each animal. Spinal cord blood flow measurements were obtained during each surgical procedure and at sacrifice. Magnetic resonance images were obtained after compression and before sacrifice. All animals in the decompressed group showed significant neurological improvement after decompression; no spontaneous improvement in neurological function was seen in the compressed group. On pathological examination, irreversible changes including large motor neuron loss, necrosis, and cavitation were seen in four of the animals in the decompressed group and five in the compressed group. Cervical spondylotic myelopathy in humans is known to respond to decompression; this study provides further evidence that this animal model for chronic compressive cervical myelopathy accurately reflects the disease process seen in humans.
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Meng, Xiangbo, Reihane Ziadlou, Sibylle Grad, Mauro Alini, Chunyi Wen, Yuxiao Lai, Ling Qin, Yanyan Zhao und Xinluan Wang. „Animal Models of Osteochondral Defect for Testing Biomaterials“. Biochemistry Research International 2020 (28.01.2020): 1–12. http://dx.doi.org/10.1155/2020/9659412.
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The treatment of osteochondral defects (OCD) remains a great challenge in orthopaedics. Tissue engineering holds a good promise for regeneration of OCD. In the light of tissue engineering, it is critical to establish an appropriate animal model to evaluate the degradability, biocompatibility, and interaction of implanted biomaterials with host bone/cartilage tissues for OCD repair in vivo. Currently, model animals that are commonly deployed to create osteochondral lesions range from rats, rabbits, dogs, pigs, goats, and sheep horses to nonhuman primates. It is essential to understand the advantages and disadvantages of each animal model in terms of the accuracy and effectiveness of the experiment. Therefore, this review aims to introduce the common animal models of OCD for testing biomaterials and to discuss their applications in translational research. In addition, we have reviewed surgical protocols for establishing OCD models and biomaterials that promote osteochondral regeneration. For small animals, the non-load-bearing region such as the groove of femoral condyle is commonly chosen for testing degradation, biocompatibility, and interaction of implanted biomaterials with host tissues. For large animals, closer to clinical application, the load-bearing region (medial femoral condyle) is chosen for testing the durability and healing outcome of biomaterials. This review provides an important reference for selecting a suitable animal model for the development of new strategies for osteochondral regeneration.
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Rypula, K., M. Porowski, J. Kaba, M. Gorczykowski und A. Deniz. „Effect of Isosporiasis Prevention with Toltrazuril on Long-Term Pig Performance“. Scientific World Journal 2012 (2012): 1–4. http://dx.doi.org/10.1100/2012/486324.
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The efficacy of toltrazuril treatment was assessed in two experiments in Polish swine herds. Experiment 1 included a toltrazuril treatment group, Group A (n=410), and untreated control, Group B (n=386). Time to sale in Group A was 108 days versus 120 days for Group B, with average body weights at sale of 114.2 kg and 108.8 kg, respectively (P<0.05). In experiment 2, the health status and body weight gain of 238 piglets treated with toltrazuril (Group D) were compared to 235 untreated piglets (Group K). A similar difference was observed in average body weights of slaughtered animals, being on average 104 kg in Group D and 101 kg in Group K (P<0.01). Animals from Group D were slaughtered 5 days earlier than animals from Group K (day 166 versus day 171). Data from clinical trials suggest treatment of coccidiosis with toltrazuril offering potential for improved animal welfare and yields, however this has remained unproven in field conditions in large swine production facilities. The present study confirms the efficacy of toltrazuril treatment when used in the field and the subsequent positive impact on time to weaning, time to market, and on weight gain at all time points.
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Scott, T. A. „Impact of wet feeding wheat-based diets with or without enzyme on broiler chick performance“. Canadian Journal of Animal Science 82, Nr. 3 (01.09.2002): 409–17. http://dx.doi.org/10.4141/a01-077.
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Two studies were conducted to determine the effect of wheat source on voluntary feed intake when diets were offered in a wet or dry form. The first experiment was designed to establish if a mould inhibitor was necessary. The second experiment allowed more extensive screening of wheat types to determine if there is a genetic component in wheat that explains the differences observed in exp. 1. Experiment 1 was based on two wheat cultivars [Hard Red Spring (HRS) and Durum]. Each wheat was ground, one portion was used as is, the other pelleted and re-ground. The four wheat sources were included at 80% of a standard bioassay diet (with enzyme) and each diet was fed with or without propionic acid. The eight diets were fed ad libitum as is or with 1.2 g water per gram of feed. The wet diets were prepared daily and all diets were fed to four groups of six male broilers from 1 to 17 d of age. The second experiment utilized three cultivars each of HRS and Durum wheat fed in similar bioassay diets with no pre-pelleting or added mould inhibitor; each diet was fed with or without enzyme. Each of the 12 diets in the second experiment was fed with and without 1.2 g water per gram of feed to six groups of eight male broilers from 1 to 21 d of age. For both experiments, the daily intake of feed, on an air-dried basis, was detennined for each diet and used to calculate feed conversion for the respective feeding periods. Experiment 1 showed no effect of supplementing the wheat-based diets with propionic acid. This same experiment also clearly showed that feed intake was increased with wet feeding and there were significantly greater effects when HRS as compared to Durum wheat was fed. Experiment 2 clearly established that there are distinct differences in voluntary feed intake with wet feeding utilizing HRS as compared to Durum wheat. This experiment indicated that wet feeding mimics enzyme supplementation with regard to lowering digesta viscosity, but it is clearly unique from enzyme supplementation with its large effect on feed intake and growth. These studies support our hypothesis that variability in hydration rate of cereal-based diets may limit intake. Key words: Wheat, wet feeding, enzymes, feed intake, broilers
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Strickler, Stephanie A., und P. L. Schwagmeyer. „An Experimental Test of Kin Recognition in Harvester Ants“. American Biology Teacher 73, Nr. 7 (01.09.2011): 396–400. http://dx.doi.org/10.1525/abt.2011.73.7.5.
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Many animals direct assistance selectively toward relatives and/or aggression toward non-relatives; the ability to differentiate between kin and non-kin should evolve when doing so incurs fitness benefits. We detail a field-based experiment that tests whether workers of a large-bodied, abundant, and hardy seed-harvester ant are capable of kin recognition. We use this exercise in an undergraduate animal-behavior class to introduce concepts associated with eusocial insects and the study of kin recognition, as well as to reinforce principles of hypothesis testing, experimental design, and scientific writing. Students collect data, analyze and interpret results, and write a formal report; this experiment is one of several we use as models to prepare students for designing and performing their own follow-up studies.
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Quiniou, N., J. Y. Dourmad und J. Noblet. „Effect of energy intake on the performance of different types of pig from 45 to 100 kg body weight. 1. Protein and lipid deposition“. Animal Science 63, Nr. 2 (Oktober 1996): 277–88. http://dx.doi.org/10.1017/s1357729800014831.
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AbstractBetween 45 and 100 kg body weight, Large White castrated males (cLW), and crossbred Pietrain × Large White castrated males fcPP×) and boars (bPP×) were either given food ad libitum in experiment 1 or allocated to four energy levels (0·70, 0·80, 0·90, 1·00 ad libitum) in experiment 2. Daily protein and amino acid supplies were calculated to be non-limiting for growth. Protein (PD) and lipid (LD) deposition rates were measured according to the comparative slaughter technique over the whole experimental period (experiments 1 and 2) and according to the nitrogen and energy balance technique at four stages of growth: 48, 64, 79 and 94 kg mean body weight (experiment 2). Average daily gain increased linearly with metabolizable energy (ME) intake, the slope of the relationship being significantly different between types of pig (from −28 to +36 g per additional MJ ME). Daily PD increased with ME intake above maintenance (MEp) according to a linear-plateau relationship in the three types of pig: the slope was significantly affected by type of pig (from +3·4 to 6·0 g per extra MJ MEp) but not by stage of growth. Daily LD increased linearly with MEp intake; neither the type of pig nor the stage of growth affected its slope (+13-5 g per extra MJ MEp). The LD/PD ratio in the extra body-weight gain associated with increased energy intake was affected only by the type of pig.
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Belpoggi, Fiorella, Morando Soffritti und Cesare Maltoni. „Methyl-Tertiary-Butyl Ether (MTBE) — a Gasoline Additive — Causes Testicular and Lympho Haematopoietic Cancers in Rats“. Toxicology and Industrial Health 11, Nr. 2 (März 1995): 119–49. http://dx.doi.org/10.1177/074823379501100202.
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In the framework of a series of experiments conducted to evaluate the carcinogenic effects of oxygenated gasoline additives, MTBE was analyzed in an oral lifetime carcinogenicity study using 8-week-old male and female Sprague- Dawley rats. These experiments were part of a large research project on gasoline carcinogenicity performed at the Bentivoglio (BT) Castle Cancer Research Center of the Ramazzini Foundation and of the Bologna Institute of Oncology. MTBE, dissolved in oil, was administered by stomach tube at the doses of 1000, 250, or 0 mg/kg b.w., once daily, four days weekly, for 104 weeks. The animals were maintained until natural death. The last animal died 166 weeks after the start of the experiment, i.e., at 174 weeks of age. Under the tested experimental conditions, MTBE was shown to cause an increase in Leydig interstitial cell tumors of the testes and a dose-related increase in lymphomas and leukemias in female rats.
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Delong, Michael D., R. Brent Summers und James H. Thorp. „Influence of Food Type on the Growth of a Riverine Amphipod, Gammarus fasciatus“. Canadian Journal of Fisheries and Aquatic Sciences 50, Nr. 9 (01.09.1993): 1891–96. http://dx.doi.org/10.1139/f93-211.
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A laboratory experiment and natural-diet study were conducted to examine the feeding ecology and importance of food type for growth of Gammarus fasciatus from the Ohio River. To determine effects on growth, amphipods were fed four diets: (1) filamentous algae (Cladophora) and diatoms, (2) dead animal matter (chironomids), (3) coarse particulate organic matter (CPOM), and (4) fine particulate organic matter (FPOM). Organic matter was obtained by shredding preconditioned sycamore leaves (Platanus occidentalis). Growth was evaluated from weekly measurements of head length. There were no significant differences in growth among food types before week 3 of the experiment, but from week 4 to week 6, amphipods fed algae and dead animal matter were significantly larger than those maintained on CPOM and FPOM. Gut analysis of natural populations showed that G. fasciatus consumed all food types used in the laboratory study. The weighted proportions of filamentous algae and animal matter in riverine populations increased consistently from smallest to largest size-class. The availability of, and ability to use, algae and animal matter by G. fasciatus benefits natural populations in large rivers by enabling them to exploit seasonal changes in the relative abundance of different food sources.
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Bashaw, Meredith J., Mollie A. Bloomsmith, M. J. Marr und Terry L. Maple. „To hunt or not to hunt? A feeding enrichment experiment with captive large felids“. Zoo Biology 22, Nr. 2 (2003): 189–98. http://dx.doi.org/10.1002/zoo.10065.
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Pinares-Patiño, C. S., A. Machmüller, G. Molano, A. Smith, J. B. Vlaming und H. Clark. „The SF6 tracer technique for measurements of methane emission from cattle – effect of tracer permeation rate“. Canadian Journal of Animal Science 88, Nr. 2 (01.06.2008): 309–20. http://dx.doi.org/10.4141/cjas07117.
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Previous experiments have suggested that estimates of methane (CH4) emissions from ruminant animals made using the sulphur hexafluoride (SF6) tracer might be influenced by the permeation rate of SF6 (PR). This study examined the latter issue with cattle. For this, analyses of data sets from two grazing trials involving large herds (exps. 1 and 2) and a specifically designed controlled trial (exp. 3) were conducted. Individual daily CH4 emissions from 296 (exp. 1) and 388 (exp. 2) Friesian × Jersey cows in mid-lactation were measured with herds subdivided into four (exp. 1) or five (exp. 2) measurement groups and dry matter intake (DMI) estimated by energy metabolism algorithms. The ranges of tracer PR in exps. 1 and 2 were 2.624–5.689 and 2.214–3.594 mg d-1, respectively. Experiment 3 was conducted using 12 rumen-fistulated beef steers pen-fed on lucerne silage and design arranged as a 4 × 4 Latin square with three replications. Permeation tubes with four levels of nominal PR (three tubes each): low (L), medium (M), medium-high (MH) and high (H) were randomly assigned to four rumen deployment sequences (L-M-MH-H, H-MH-M-L, MH-L-H-M and M-H-L-MH). The grazing experiments revealed a positive effect of PR on the CH4 emission estimates (1 mg SF6 d-1 accounting for 0.6–2.3 g kg-1 DMI), but this effect was significant (R2 = 0.06–0.23, P < 0.05) only when there was a large range in PR (exp. 1), whereas with a narrower PR range (exp. 2) the effect was not significant (R2 < 0.04, P > 0.05). Experiment 3 revealed that the influence of PR upon CH4 emission estimates was linear. It is concluded that despite an influence of PR on CH4 emission estimates, accuracy and precision of the tracer technique is warranted provided that PR are used in a narrow range and balanced between the experimental treatments. Key words: Methane, permeation rate, SF6 tracer, cattle, variation
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Oatway, M. L., und D. W. Morris. „Do animals select habitat at small or large scales? An experiment with meadow voles (Microtus pennsylvanicus)“. Canadian Journal of Zoology 85, Nr. 4 (April 2007): 479–87. http://dx.doi.org/10.1139/z07-023.
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Habitat and patch use are crucial to the dynamics of populations and the structure of ecological communities. But ecologists have not rigorously tested whether animals choose habitat at small or large scales. If individuals base their patch and habitat choices on fine-scale differences in habitat, then their use of different sites should correspond with measures of microhabitat at those sites. But if individuals use density to assess and respond to habitat at larger spatial scales, then site use should correspond with the scale of density-dependent habitat selection. We tested these predictions with experiments that measured microhabitat and monitored the use of capture sites by meadow voles ( Microtus pennsylvanicus Ord, 1815) in 0.25 ha old-field enclosures. We varied the density of voles in pairs of adjacent enclosures and tested for density-dependent habitat selection. Then we assessed whether their frequency of captures at trapping stations was best predicted at the small scale of microhabitat or at the much larger scale of enclosures where density varied. The voles selected habitat at different scales. When the use of enclosures was predicted by density, the scale of density-dependent choice trumped the use of small-scale patches. And when voles selected amongst different small-scale patches, their use of enclosures was independent of density. These results suggest that assessments of spatial scale in habitat use must include tests for both scale- and density-dependent habitat choice.
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Artukhina, E. A., V. A. Vaskovskiy, A. A. Venediktov, S. V. Evdokimov, S. S. Durmanov, I. A. Evtjushkin, V. V. Bazylev und A. Sh Revishvil. „EVALUATION OF THE FUNCTIONAL PROPERTIES OF A BIOLOGICAL CASE FOR IMPLANTABLE CARDIAC DEVICES, IMPREGNATED WITH BIOACTIVE SUBSTANCES IN AN EXPERIMENT ON LARGE LABORATORY ANIMALS“. Siberian Medical Journal 34, Nr. 2 (11.07.2019): 118–28. http://dx.doi.org/10.29001/2073-8552-2019-34-2-118-128.
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Aim. The purpose of the experimental study was to determine the functional properties of the case with antibacterial and hemostatic preparations impregnated on it, to assess the biological safety and the effectiveness of using this medical device in an in vivo model on large laboratory animals (pigs).Material and Methods. The article presents the first results of an experimental study of a domestic extracellular collagen matrix-based biological case “Bio-NEST” for implantable cardiac devices, impregnated with bioactive substances, in an in vivo experiment on large laboratory animals. The experiment was conducted in three chronological stages to analyze and evaluate the safety, efficacy, and histological compatibility of the biological sheath during implantation and reimplantation of cardiac devices using bioactive substances (antibacterial, hemostatic, and their combinations) as well as under the conditions of the established model of infection with pathogenic microflora implant pocket.Results. Results of the study showed that the use of the experimental cover sample was safe for a laboratory animal. Experimental samples were biocompatible and did not cause inflammatory and immune responses. Implantation of cardiac devices in the sample of the case allowed preventing implant migration and development of infectious inflammation of the implant bed when the experimental cover was impregnated with a solution of rifampicin and aminocaproic acid.
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Lisiak, Dariusz, Piotr Janiszewski, Tadeusz Blicharski, Karol Borzuta, Eugenia Grześkowiak, Beata Lisiak, Krzysztof Powałowski et al. „Effect of selenium supplementation in pig feed on slaughter value and physicochemical and sensory characteristics of meat“. Annals of Animal Science 14, Nr. 1 (01.03.2014): 213–22. http://dx.doi.org/10.2478/aoas-2013-0063.
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AbstractThe aim of the study was to examine the assimilability of organic and inorganic selenium supplied as an additive to pig feed. The influence of both selenium forms on pig slaughter value as well as on the physicochemical and sensory characteristics of meat was also examined (experiment I). An attempt to establish the distribution of selenium in the body of experimental fatteners was made (experiment II). Experiment I was performed on 20 carcasses of crossbred pigs of (Polish Large White × Polish Landrace) × Duroc genotype and experiment II was carried out on 45 samples of longissimus and semimembranosus muscles taken from fatteners of the same genotype (PLW × PL × Duroc). The results obtained indicated that selenium supplementation in the diet had no impact on slaughter performance, meat quality and most physicochemical and sensory characteristics of meat. Selenium was found to have no significant effect on meat colour. The meat water holding capacity (WHC) was lower in the group of pigs fed organic selenium. The highest selenium concentration was found in the semimembranosus muscle of fatteners receiving the inorganic selenium additive.
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Sillence, M. N., K. M. Thomas, H. Anil, E. J. Redfern und R. G. Rodway. „Adrenal function in lambs treated with androgenic and oestrogenic growth stimulants“. Animal Science 44, Nr. 2 (April 1987): 241–49. http://dx.doi.org/10.1017/s0003356100018602.
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ABSTRACTThree experiments were carried out in which plasma cortisol concentrations were measured hourly in lambs treated with various anabolic steroids. In the first experiment, female lambs were implanted with trenbolone acetate (TBA) and plasma cortisol was measured for 24-h periods 4 weeks after implantation and 1 week after reimplantation. Plasma cortisol levels were unaltered 4 weeks after treatment, but were found to be significantly lower 1 week after retreatment. On this occasion, peak concentrations of cortisol after ACTH challenge were also reduced by TBA. In the second experiment, female lambs were implanted with a mixture of TBA and oestradiol and plasma cortisol measured 1 and 4 weeks later. Results were similar to the first experiment although the reduction in plasma cortisol was less. In the third experiment, castrated male lambs were implanted with either TBA, TBA plus oestradiol or a long-acting oestradiol implant. In this experiment, only oestradiol affected plasma cortisol levels, causing a large elevation. All three treatments stimulated growth. Measurement of bound and free cortisol concentration in the third experiment indicated that oestradiol treatment tended to increase the proportion of cortisol present in the free form.These results suggest that an inhibition of cortisol secretion may be important in the anabolic response of female sheep to TBA. In the male, however, cortisol concentrations are naturally lower and are not further reduced by TBA treatment.Plasma insulin concentrations were also measured in the castrated males. Neither TBA nor the combined implant altered insulin levels, but oestrogen treatment resulted in a small increase in insulin. The diurnal pattern of plasma insulin closely paralleled that of cortisol.
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De Oliveira Gonzaga, Marcelo, und João Vasconcellos-Neto. „INFLUENCE OF COLLECTIVE FEEDING ON WEIGHT GAIN AND SIZE VARIABILITY OF ANELOSIMUS JABAQUARA LEVI 1956 (ARANEAE: THERIDIIDAE)“. Behaviour 139, Nr. 11-12 (2002): 1431–42. http://dx.doi.org/10.1163/15685390260514708.
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AbstractDifferences in the size and weight of spiders within colonies may be an important factor for determining dispersion and food distribution among nestmates. In this study we report on the variation in size of spiders from 27 colonies of A. jabaquara, collected during one year. We also conducted an experiment under laboratory conditions to test if prey size, and consequently, collective or individual capture behaviours, influence the establishment of weight differences. Female size variation within colonies was high, increasing slightly from March to September. However, from November to January the variation was much lower, probably as a consequence of the emigration of large spiders during the reproductive period. Spiders that fed on large flies in the laboratory experiment grew more and collective feeding seemed to induce a larger variation in weight among individuals. These results indicate that collective feeding promotes an unequal distribution of food in A. jabaquara colonies.
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Taniguchi, Daisuke, Keitaro Matsumoto, Yoshihiro Kondo, Koichiro Shimoyama, Yasumasa Hashimoto, Abdelmotagaly Elgalad, Tomohiro Obata et al. „Balloon-Based Organ Retractor With Increased Safety and Reduced Invasiveness During Video-Assisted Thoracoscopic Surgery“. Surgical Innovation 25, Nr. 5 (02.07.2018): 435–43. http://dx.doi.org/10.1177/1553350618784473.
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Objectives. In recent years, video-assisted thoracoscopic surgery (VATS) has increasingly become the preferred technique for thoracic surgery. However, the inherent characteristics of the lungs as large, soft, slippery, and delicate creates difficulties for pulmonary surgery. In this article, we outline the development and assessment of a balloon-based organ retractor for VATS via collaboration between medical and engineering personnel. Methods. A dry lab trial and accompanying questionnaire assessment were performed by a group of thoracic surgeons. Objective pressure measurements were obtained, and animal experiment on pigs was performed. Results. In the dry lab trial, use of the developed organ retractor required significantly less time and resulted in fewer difficulties than using a Cherry Dissector. The measured pressure per mm2 of the developed retractor was clearly lower than that for the Cherry Dissector. The questionnaire completed by the surgeons following the dry lab and animal experiments showed that most of the surgeons (7 surgeons out of 9) were satisfied with the quality of the balloon-based retractor based on a score of 3.13 ± 0.28 (mean ± standard deviation) out of 4.0. During the animal experiment, the balloon-based retractor provided stable and clear viewing with minimal need for adjustment. Conclusion. This balloon-based retractor could contribute to increased safety and less-invasive VATS.
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Rosendorf, Jachym, Marketa Klicova, Lenka Cervenkova, Jana Horakova, Andrea Klapstova, Petr Hosek, Richard Palek et al. „Reinforcement of Colonic Anastomosis with Improved Ultrafine Nanofibrous Patch: Experiment on Pig“. Biomedicines 9, Nr. 2 (21.01.2021): 102. http://dx.doi.org/10.3390/biomedicines9020102.
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Anastomotic leakage is a dreadful complication in colorectal surgery. It has a negative impact on postoperative mortality, long term life quality and oncological results. Nanofibrous polycaprolactone materials have shown pro-healing properties in various applications before. Our team developed several versions of these for healing support of colorectal anastomoses with promising results in previous years. In this study, we developed highly porous biocompatible polycaprolactone nanofibrous patches. We constructed a defective anastomosis on the large intestine of 16 pigs, covered the anastomoses with the patch in 8 animals (Experimental group) and left the rest uncovered (Control group). After 21 days of observation we evaluated postoperative changes, signs of leakage and other complications. The samples were assessed histologically according to standardized protocols. The material was easy to work with. All animals survived with no major complication. There were no differences in intestinal wall integrity between the groups and there were no signs of anastomotic leakage in any animal. The levels of collagen were significantly higher in the Experimental group, which we consider to be an indirect sign of higher mechanical strength. The material shall be further perfected in the future and possibly combined with active molecules to specifically influence the healing process.
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Gillan, L., K. Skovgold, P. F. Watson, W. M. C. Maxwell und G. Evans. „Fate and functional integrity of fresh and frozen - thawed ram spermatozoa following intrauterine insemination“. Reproduction, Fertility and Development 11, Nr. 6 (1999): 309. http://dx.doi.org/10.1071/rd99074.
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Ewes in a synchronized oestrus were inseminated (intrauterine) with fresh and frozen–thawed spermatozoa and the spermatozoa were either recovered from each section of the reproductive tract after the animal was killed (Experiments 1a and 1b) or after they were voided from the cervix (Experiment 2). In Experiment 1a, only 1.2 0.27% of the original inseminate was recovered. Placing a ligature at the base of the uterine horn in Experiment 1b led to the recovery of 3.0 0.33% of the original inseminate, located mainly in each uterine horn (33.1 5.48%), and each isthmic and ampullary region of the oviduct (2.9 5.48% and 4.0 5.48%, respectively). A higher proportion of spermatozoa recovered from the isthmus were uncapacitated when observed by chlortetracycline staining than those recovered from the uterus (26.4 1.92% and 15.6 1.92%, respectively, P<0.05). Experiment 2 showed that large proportions of spermatozoa were voided from the tract through the vagina, with similar numbers of fresh and frozen–thawed spermatozoa lost from the tract. However, frozen–thawed spermatozoa were lost at a faster rate than fresh (P<0.05) and with a more advanced membrane state (66.8 1.30% and 53.2 1.30% were acrosome reacted respectively; P<0.001). Large numbers of recovered spermatozoa had lost their tails, with frozen–thawed spermatozoa more susceptible to tail loss than fresh spermatozoa (55.0 0.96% and 45.5 0.96% respectively; P<0.05).
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Turri, Maria Grazia, Norman D. Henderson, John C. DeFries und Jonathan Flint. „Quantitative Trait Locus Mapping in Laboratory Mice Derived From a Replicated Selection Experiment for Open-Field Activity“. Genetics 158, Nr. 3 (01.07.2001): 1217–26. http://dx.doi.org/10.1093/genetics/158.3.1217.
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Abstract Bidirectional selection in rodents has been used to derive animal models of human behavior. An important question is whether selection for behavior operates on a limited number of QTL or whether the number and individual contribution of QTL varies between selection experiments. To address this question, we mapped QTL in two large F2 intercrosses (N = 815 and 821) from the four lines derived from a replicated selection experiment for open-field activity, an animal model for susceptibility to anxiety. Our analyses indicate that selection operated on the same relatively small number of loci in both crosses. Haplotype information and the direction of effect of each QTL allele were used to confirm that the QTL mapped in the two crosses lie in the same chromosomal regions, although we were unable to determine whether QTL in the two crosses represent the same genes. We conclude that the genetic architecture of the selected strains is similar and relatively simple.
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Ball, N., M. J. Haskell, J. L. Williams und J. M. Deag. „Investigating temperament traits in cattle for quantitative trait loci (QTL) identification“. Proceedings of the British Society of Animal Science 2002 (2002): 66. http://dx.doi.org/10.1017/s1752756200007225.
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Farm animals show individual variation in their behavioural responses to handling and management systems on farms. These behavioural responses are presumed to reflect underlying temperament traits such as fear or aggression. Information about the location of genes that influence temperament traits could be used in selective breeding programmes to improve animal welfare, as selection for desirable behavioural responses would increase the ability of animals to cope with stressors encountered on farms. The aims of this study were to obtain reliable temperament measurements in cattle using behavioural tests, and to use this data to localise the genes (quantitative trait loci) that are involved in such traits.Behavioural data obtained in temperament tests must be shown to reflect underlying traits by demonstrating intra-animal repeatability, inter-animal variability and validity. The objectives of this experiment were i) to carry out four behaviour tests on a group of heifers, and examine the repeatability, variability and validity of the results obtained; ii) to correlate the behavioural data with genotyping data from a large number of heifers to look for associations between behavioural phenotypes and genetic markers. Associations localise quantitative trait loci (QTLs), or regions of the genome, that are involved in these traits.
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Istasse, L., C. Van Eenaeme, P. Baldwin, G. Maghuin-Rogister und J. M. Bienfait. „Animal performances, plasma hormones and metabolites in Holstein and Belgian Blue growing fattening bulls“. Proceedings of the British Society of Animal Production (1972) 1989 (März 1989): 135. http://dx.doi.org/10.1017/s0308229600011259.
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Meat production is a complex process in which the absorbed nutrients are directed under hormonal control towards muscle growth. According to consumer's standards a high quality carcass should contain a large proportion of lean meat and a small amount of fat. In Western Europe, cattle meat is produced both by beef and dairy breeds used as pure breeds or breed crosses. Holstein and Belgian Blue - double muscled type - are 2 extreme breeds in terms of meat production. The aim of the present experiment was to relate animal performances with plasma hormones and metabolites in these 2 breedsSix Holstein bulls and 6 bulls from the Belgian Blue - double muscled type - were used. They were 4 and 6 months old respectively on the beginning of the experiment. They were kept in metabolism stalls. The fattening diet was based on dried sugar beet pulp supplemented with soja bean meal, rolled barley, hay, minerals and vitamins. The amounts of feed given were weighed daily. Live weight was recorded once weekly.
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Todd, Peter A., Huijia Phua und Kok Ben Toh. „Interactions between background matching and disruptive colouration: Experiments using human predators and virtual crabs“. Current Zoology 61, Nr. 4 (01.08.2015): 718–28. http://dx.doi.org/10.1093/czoolo/61.4.718.
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Abstract Interactions between disruptive colouration and the match between prey and background spot size were manipulated in two experiments that used time taken by human ‘predators’ to find artificial prey (virtual crab morphs) against heterogeneous backgrounds as a measure of the their camouflage. Experiment 1, in which the spots and their placement imitated the arrangement on the crab Carcinus maenas, tested whether high and low contrast spots touching the body outline (disruptive ‘edge’ morphs) made the artificial prey more difficult to detect than when the spots did not touch the outline (non-disruptive ‘inner’ morphs) against three different backgrounds: ‘small’, ‘middle’ and ‘large’ spot size. In Experiment 2, the range of spot sizes and their positions (‘edge’ and ‘inner’) on the crab morphs were varied to determine the most effective combination against the ‘middle’ background. Altogether, 640 volunteers participated in these computer trials, representing a high degree of independent replication. All patterned morphs were significantly harder to detect than plain morphs, indicating that possessing at least some degree of background matching can provide camouflage. Both experiments demonstrated that various morphs, though not having the same spot sizes as the background, had similar or better survivorship as those with matching spot sizes—indicating that optimal camouflage did not come from background matching alone. In Experiment 2, edge-disrupted morphs consistently took longer to find than their non-disruptive counterparts. The relative effects of edge disruption, contrast, and background/prey spot size are clearly context-dependent, highlighting the complexity of prey concealment.
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Semenova, A. A., A. I. Sinichkina, I. V. Kozyrev und T. M. Mittelstein. „An effect of the animal condition after gas stunning on quality of slaughter products from Large White pigs“. Theory and practice of meat processing 5, Nr. 2 (01.08.2020): 39–44. http://dx.doi.org/10.21323/2414-438x-2020-5-2-39-44.
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The aim of the research was to establish an effect of gas stunning of pigs at slaughter on the condition of the internal organs and pork functional-technological characteristics. The experiment was carried out in the conditions of the operating enterprise on 37 Large White pigs. When using 94% concentration in a chamber, only 65% of animals were assessed as normally stunned, 30% of animals did not have cardiac activity and were considered dead, 5% of animals retained sensibility. Assessment of the condition of the internal organs, dynamics of pH changes, comparison of moisture holding capacity and color characteristics did not reveal substantial and statistically significant differences between slaughter products from normally stunned animals and animals died during stunning. The authors discuss mortality of animals before the beginning of bleeding as a possible cause of similar results of investigation of the internal organs and meat quality from animals with and without cardiac activity after gas stunning.