The source of autumn and spring downstream migrating juvenile Atlantic salmon in a small lowland river     

Anton T. Ibbotson  William D. Riley  William R.C. Beaumont  Alastair C. Cook  Mark J. Ives  Adrian C. Pinder  Luke J. Scott 《Ecology of Freshwater Fish》2013,22(1):73-81

Over 3 years, 32,444 age‐0 group Atlantic salmon (Salmo salar) parr tagged with passive integrated transponder tags throughout the River Frome catchment were assigned to one of three groups, nonmigrants, autumn migrants and spring smolts, depending on the detection and the timing of detection at downstream tag readers (situated 8.6 km above the tidal limit). We examined the effect of density at the time of tagging (n·m^?2), distance upstream from the tidal limit (km), fish length (mm), Fulton condition index, habitat type (divided into two types, main river and carrier), days after 1 September that each fish was tagged and year (replication) on the proportions of fish in each of the migration groups. Distance upstream from tidal limit was strongly negatively related to the proportion of autumn migrants and positively related to the proportion of spring smolts. Nonmigrants had a lower average body size than migrants, although there were no differences in the sizes of autumn migrants and spring smolts in September prior to migration. Fish density had no effect on migration strategy. A lower proportion of fish migrated as autumn migrants from the smaller carrier habitats than the main river channel. There is some evidence that those parr destined to become autumn migrants underwent a lower mortality rate during September before tagging than those destined to become spring migrants indicating possible physiological or behavioural differences between these two groups of fish at that time. More research into the factors responsible for initiating the autumn migration is required.  相似文献   

KKM, PBB, MVGK = milk from healthy cows?     

van der Paauw A 《Tijdschrift voor diergeneeskunde》2002,127(1):18-20

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Effect of diet on the feces quality in javan langur (Trachypithecus auratus auratus).     

Joeke Nijboer  Marcus Clauss  Moniek Olsthoorn  Wendy Noordermeer  Tjalling R Huisman  Celine Verheyen  Jan van der Kuilen  W Streich Jürgen  Anton C Beynen 《Journal of zoo and wildlife medicine》2006,37(3):366-372

A high intake of easily fermentable carbohydrates and a low intake of fiber material are generally regarded as major factors affecting the health of captive langurs. The effect on fecal consistency of excluding fruits and vegetables from the diet was evaluated in Javan langurs (Trachypithecus auratus auratus). Cross-over trials were carried out at Rotterdam Zoo and at the Apenheul Zoo, The Netherlands. During the first and third dietary period, the langurs were fed their usual diet, which contained fruits, vegetables, langur pellets, and browse. During the second period, the vegetables and fruits were excluded from the diet and the diet essentially consisted of pellets and browse. Feces consistency was scored using a fecal score chart developed for langurs. During the second feeding period the feces consistency improved significantly in animals at both zoos. Across all trials, a firmer feces consistency was correlated with an increase in dietary cell wall (measured as neutral detergent fiber) and a decrease in dietary water. It is suggested that the combined decrease in the intake of soluble sugars, the increase of fiber intake, and a lower amount of dietary water in the diet resulted in more solid stools. The results indicate that a dietary neutral detergent fiber content of approximately 46% in dry matter will result in a feces consistency indicative of undisturbed gut function.  相似文献   

Über die Veränderungen der Sorptionseigenschaften von Wurzeln zweier Pflanzenarten während der Verrottung     

Anton Kullmann  Käte Koepke 《Archives of Agronomy and Soil Science》2013,59(4):285-297

Die Steigerung der naturalen Erträge unserer Kulturpflanzen ist gegenwärtig kein wissenschaftlicher Arbeitsgegenstand der produktionsorientierten landwirtschaftlichen Forschung. Es bestehen häufig Bedenken, daß mit einer zunehmenden Ertragshöhe unerwünschte Wirkungen auf die Umwelt verbunden sind.

An ausgewählten Beispielen wird dargelegt, daß es zum einen nicht möglich ist, aus der Ertragshöhe oder den Ertragssteigerungen pauschal auf negative Umweltwirkungen der ackerbaulichen Produktion zu schließen. Zudem wird diskutiert, welche Bedeutung die Steigerung der Erträge von Kulturpflanzen für die Sicherung der technologischen, aber auch der ökologischen Ansprüche hat.

Ein Rückgang der Forschungs‐ und Publikationsleistungen zu Anbauverfahren bzw. dem Ertragsmanagement wird für die letzten Jahre dargelegt und dessen Bedeutung für die wissenschaftlichen Arbeiten der landwirtschaftlichen Produktion erörtert.  相似文献   

A bioactive biflavonoid from Campnosperma panamense     

Weniger B  Vonthron-Sénécheau C  Arango GJ  Kaiser M  Brun R  Anton R 《Fitoterapia》2004,75(7-8):764-767

Lanaroflavone (1), a biflavonoid isolated from the methanol extract of the aerial part of Campnosperma panamense by bioguided fractionation, has been assessed for in vitro antiprotozoal activity. Lanaroflavone showed both antimalarial and leishmanicidal activities, but was inactive against Chagas disease vector, Trypanosoma cruzi.  相似文献   

Exercising the Pregnant Mare from Day 16 to Day 80 of Gestation     

Jason E. Anton  Kristine L. Vernon  Dale E. Kelley  John R. Gibbons  Glen Birrenkott  Chris J. Mortensen 《Journal of Equine Veterinary Science》2014

Our previous research has demonstrated moderate exercise can be detrimental to early pregnancy in the mare, but little work has examined exercise after pregnancy has been detected. We exercised mares (n = 8) 6 days a week for 45 min from Day 16 until Day 80 of gestation. Color Doppler ultrasonography was used to evaluate embryonic vesicle size, fetal length, and uterine blood flow. Blood was sampled every other day to analyze cortisol and progesterone concentrations. Results indicated that exercising pregnant mares (n = 4) led to greater (P < .01) cortisol concentrations 30 min after the exercise period. No overall treatment effect could be detected in progesterone concentrations; however, following Day 60 of gestation, progesterone concentrations were lower (P < .05) in exercised mares. Additionally, progesterone concentrations peaked earlier in exercised mares at Day 52 of gestation compared to peak levels at Day 68 of gestation for control mares. No significant effects were detected in embryonic vesicle size. Fetal length tended (P = .06) to be longer in the conceptus of exercised mares. Uterine blood flow did not differ between groups but increased as pregnancy progressed (P < .001) in both groups. All mares in this study went on to deliver healthy foals and suffered no difficulties during parturition. These results indicated that moderate exercise was not detrimental to mare pregnancy.  相似文献   

A model ensemble approach to determine the humus building efficiency of organic amendments in incubation experiments     

Anton A. Gasser  Julius Diel  Kerstin Nielsen  Paul Mewes  Christof Engels  Uwe Franko 《Soil Use and Management》2022,38(1):179-190

Organic amendments are important to sustain soil organic matter (SOM) and soil functions in agricultural soils. Information about the contribution of organic amendments to SOM can be derived from incubation experiments. In this study, data from 72 incubated organic amendments including plant residues, digestates and manure were analysed. The incubation data was compiled from three experimental setups with varying incubation times, soils and incubation temperatures, in which CO₂ release was measured continuously. The analysis of the incubation data was performed with an approach relying on conceptual parts of C-TOOL, CCB, Century, ICBM, RothC and Yasso which are all well-approved first-order carbon models that differ in structure and abstraction level. All models are an approximation of reality, whereby each model differs in understanding of the processes involved in soil carbon dynamics. To accumulate the advantages from each model a model ensemble was performed for each substrate. With the ability of each carbon model to compute the distribution of carbon into specific SOM pools a new approach for evaluating organic amendments in terms of humus building efficiency is presented that, depends on the weighted model fit of each ensemble member. Depending on the organic substrate added to the soil, the time course of CO₂ release in the incubation studies was predicted with different accuracy by the individual model concepts. Averaging the output of the individual models leads to more robust prediction of SOM dynamics. The E_HUM value is easy to interpret and the results are in accordance with the literature.  相似文献   

Bioaccumulation and Effects of Heavy Metals in Crayfish: A Review     

Antonín Kouba  Miloš Buřič  Pavel Kozák 《Water, air, and soil pollution》2010,211(1-4):5-16

Metal pollution is a global problem which represents a growing threat to the environment. Because of bioaccumulation and negative effects of heavy metals, their bioavailability needs to be monitored. Many studies showed accumulation of metals in crayfish tissues as dose- and time-dependent without significant differences in tissue concentration levels comparing males and females. Muscles and exoskeleton were considered as specific for accumulation of mercury and nickel, respectively. Cadmium, zinc, copper, lead, and chromium accumulated mainly in hepatopancreas. By analyzing these specific tissues, it is possible to deduce the bioavailability and, by presumption, the level of environmental pollution by specific metals. However, in the case of zinc and copper, their utility is limited to assessing bioavailability because rapid depuration of these metals renders them less useful for long-term environmental monitoring programs. The literature reporting heavy metal impacts on freshwater crayfish, with reference to accumulation levels, is reviewed and summarized with respect to their suitability as bioindicators. Summarized published data from unpolluted or control localities can be used as referential values in crayfish, and consequently help with evaluation of monitored sites.  相似文献   

Allele distributions of two novel SNPs within the sheep Cyp19 gene     

Attila Zsolnai  István Anton  László Fésüs  one Estonba  Manfred Schwerin  Jens Vanselow 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2002,119(6):402-405

Oestrogen is an important regulator of reproduction and growth. The key enzyme of oestrogen biosynthesis, aromatase cytochrome P450, is encoded by the Cyp19 gene. In order to generate genetic markers for the sheep Cyp19 gene, two novel single nucleotide polymorphisms (SNPs), one located in promoter 2 (P2), the other one in intron 9 (I9), were identified by a comparative sequencing approach. The allele distributions of both SNPs were investigated by means of Polymerase chain reaction‐restriction fragment length polymorphism analysis (PCR‐RFLP) in five economically relevant sheep breeds (British Milk Sheep, Carranzana, Latxa Black Face, Latxa White Face, Merino) and three ancient Hungarian breeds kept as gene reserves (Cikta, Racka, Tsigai). In British Milk Sheep, only the intronic SNP was present whereas in Merino, Cikta, Racka, Tsigai, Carranzana, Latxa Black Face and Latxa White Face, both SNPs could be found. This indicates that the newly identified SNPs can be used as markers for the Cyp19 locus in various sheep breeds.  相似文献   

Traditional maintenance breeding of landraces: 2. Practical and theoretical considerations on maintenance of variation of landraces by farmers and gardeners     

Anton C. Zeven 《Euphytica》2002,123(2):147-158

Maintenance breeding of landraces is discussed. Various practical andtheoretical advices, presented in the literature to collectors of genebankshave been used to compare these with the methods applied by farmers.Although most farmers realize the utmost importance of yield stability, theyand their ancestors experienced that maintenance breeding could better bereplaced by seed replacement. A few crops such as rootstock rose andespecially maize, form exceptions. In these crops the farmers actually collect`hips', or ears for the next generation. However, they also apply seedreplacement from time to time.More research is needed to obtain better knowledge about the level ofvariation of a landrace grown for various generations before and after seedreplacement.  相似文献