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Die Milchviehhaltung und Milcherzeugung hat für die niedersächsische Landwirtschaft eine große Bedeutung. Vor allem in den Grünlandregionen erzielen die landwirtschaftlichen Betriebe ihr Einkommen maßgeblich aus der Rinderhaltung. In der öffentlichen Wahrnehmung genießt die Milchrinderhaltung gegenüber anderen landwirtschaftlichen Nutztierhaltungen ein gutes Ansehen; positive Assoziationen der Verbraucher mit der Milchviehhaltung werden im Zusammenhang mit der Weidewirtschaft gesehen. De facto ist der Anteil von den Milchviehbetrieben, die den Tieren Weidegang erlauben, seit Jahren rückläufig. Weniger als 40 % der Kühe werden ganztägig geweidet. Die Konsequenzen des sukzessiven Übergangs von einer weidebasierten zu einer rein stallbasierten Micherzeugung werden zunehmend diskutiert; vielfach fehlen aber die Grundlagen für eine wissenschaftlich fundierte Auseinandersetzung. Ziel des Forschungsverbundes Systemvergleich Milch ist es daher, die Bedingungen und Leistungen Weide und Stall basierter Systeme grundlegend zu untersuchen. Die Untersuchungen betreffen die Tiergesundheit, das Verhalten und Wohlbefinden der Tiere, die Belastung mit Parasitosen, die Umsetzbarkeit der Futternährstoffe bei der ruminalen Fermentation, die optimierte Gestaltung der Weidewirtschaft zur Bereitstellung ausreichender Mengen und Qualitäten von Weidefutter und zur Verringerung von Nährstoffverlusten, die Konsequenzen verschiedener Milcherzeugungssysteme für Umwelt, Klima und Ressourceneffizienz, die betriebswirtschaftliche Bewertung der verschiedenen Milcherzeugungsoptionen sowie die Wahrnehmung und die Präferenzen der Konsumenten von Milch. Die wissenschaftlichen Arbeiten basieren zum einen auf einem umfassenden Betriebsvergleich in Niedersachsen, bei dem Milchviehbetriebe nach dem Grad der Weidenutzung klassifiziert und im Hinblick auf die o.g. Merkmale analysiert werden. Andererseits werden unter weitgehend kontrollierbaren Bedingungen Produktionsexperimente mit klassischen experimentellen Designs durchgeführt. Hier stehen Fragen der Verwertung der Futternährstoffe auf der Weide sowie der Leistungsfähigkeit und Ressourceneffizienz der Weidewirtschaft im Vordergrund.
Marine environmental conditions are naturally changing throughout the year, affecting life cycles of hosts aswell as parasites. In particular,water temperature is positively correlatedwith the development ofmany parasites and pathogenic bacteria, increasing the risk of infection and diseases during summer. Interannual temperature fluctuations are likely to alter host?parasite interactions, which may result in profound impacts on sensitive ecosystems. In this context we investigated the parasite and bacterial Vibrionaceae communities of four common small fish species (three-spined stickleback Gasterosteus aculeatus, Atlantic herring Clupea harengus, European sprat Sprattus sprattus and lesser sand eel Ammodytes tobianus) in the Northern Wadden Sea over a period of two years. Overall, we found significantly increased relative diversities of infectious species at higher temperature differentials. On the taxon-specific level some macroparasite species (trematodes, nematodes) showed a shift in infection peaks that followed the water temperatures of preceding months, whereas other parasite groups showed no effects of temperature differentials on infection parameters. Our results show that even subtle changes in seasonal temperatures may shift and modify the phenology of parasites as well as opportunistic pathogens that can have far reaching consequences for sensitive ecosystems.
We aim to clarify the relationship between forest habitats and host-vector-parasite interactions. Such effects will be studied within a forest management gradient (i.e., land use intensity) in the Biodiversity Exploratories in order to understand the role of parasitism and vectors for birds and their health status in relation to land use and ecosystem functioning. We have three specific goals, one for each player in the triad of vectors, parasites, and their hosts: 1. To determine whether blood parasite prevalence and Rickettsia infections of birds depend on land use intensity (forest age classes and structure) at the plot level of the Biodiversity Exploratories for at least six host species representing migrants vs. non-migrants. 2. To determine the health status (immunoreaction) of birds in relation to parasitation and land use intensity (forest structure) in order to understand whether parasites trigger distinct immunoreactions in differently structured forests. 3. To determine the abundance of vectors and parasite prevalence in vectors to assess the probability of infections for birds in relation to forest structure at the plot level of the Biodiversity Exploratories. The assessment of indirect and variable effects of land use intensity on birds through parasitation is an essential step for understanding whether human land use impacts complex ecological processes and species interactions. We specifically expect to be able to understand whether vectors, and consequently also parasite transmissions, are affected by land use intensity on parasitation processes in bird populations.
The common periwinkle Littorina littorea is an ecologically important grazer and serves as the first intermediate host for several trematode species in the Baltic Sea, especially for the fluke Cryptocotyle lingua. In this series of experiments and analyses, we tested whether the food sources contributing to the diet and the habitat selection differ depending on the infection status of the periwinkle and the season. (1) A spatial pattern analysis was conducted to investigate the habitat composition and availability of food sources at the study site Möltenort, Kiel Bight (54.37°N, 10.19°E), (2) the habitat choice of the periwinkle was observed in-situ by a mark and recapture experiment, and (3) the composition of the diet of L. littorea (based on stable isotope composition of carbon and nitrogen isotopes) was analysed. All experiments were conducted in spring, summer and autumn.
Chytrid parasites are increasingly recognized as ubiquitous and potent control agents of phytoplankton, including bloom-forming toxigenic cyanobacteria. In order to explore the fate of the cyanobacterial toxin microcystins (MCs) and assess potential upregulation of their production under parasite attack, a laboratory experiment was conducted to evaluate short- and long-term variation in extracellular and intracellular MC in the cyanobacteria Planktothrix agardhii and P. rubescens, both under chytrid infection and in the presence of lysates of previously infected cyanobacteria. MCs release under parasite infection was limited and not different to uninfected cyanobacteria, with extracellular toxin shares never exceeding 10%, substantially below those caused by mechanical lysis induced by a cold-shock. Intracellular MC contents in P. rubescens under infection were not significantly different from uninfected controls, whereas infected P. agardhii showed a 1.5-fold increase in intracellular MC concentrations, but this was detected within the first 48 hours after parasite inoculation and not later, indicating no substantial MC upregulation in cells being infected. The presence of lysates of previously infected cyanobacteria did not elicit higher intracellular MC contents in exposed cyanobacteria, speaking against a putative upregulation of toxin production induced via quorum sensing in response to parasite attack. These results indicate that chytrid epidemics can constitute a bloom decay mechanism that is not accompanied by massive release of toxins into the medium. © 2022 Elsevier
80Prozent of the Vietnamese population inhabits rural areas, which are dominated by agriculture. After rice production, animal husbandry is the 2nd most important agricultural activity. In the mountainous area of northwestern Vietnam, livestock production is mainly done in smallholder farms, with each farmer keeping small numbers of a variety of species including pigs, cattle, buffaloes, goats and poultry. Within this area dominated by economic constraints, smallholder farming differs according to the distance to towns where market outlets exist. While farmers in valleys (near roads or towns) use e.g. pig production for income generation, the more remote mountain slopes are dominated by subsistence farming. In adaptation to this, different husbandry practices exist, and different animal species / breeds are raised. Generally, pigs are the most important animal species both as a meat source and for sale. While local pig genotypes are gradually being replaced by high yielding exotic breeds in large areas of Vietnam, this development is only slowly reaching the more remote areas of the northwest. Presently, aspects of resource utilization with regard to different animal breeds are under investigation (cf. sub-project D2.2 (Livestock effiency)). However, the impact of this development on aspects of veterinary and public health importance have not been addressed so far, although the transmission of economically important livestock pathogens and zoonotic diseases are intricately linked to husbandry practices and animal genotypes. Several species of livestock parasites not only have economic importance due to their impact on the quality and quantity of animal products, but are causative agents for human disease. Due to the complex life cycles of most parasites - which involve different host species and obligatory host changes - the locally prevailing conditions of animal husbandry, slaughtering facilities and marketing practises have a drastic influence on the transmission intensity. Many parasitic diseases can be effectively controlled by improved slaughtering practises (meat inspection) and information on preventive behaviour to farmers and distributors. However, small scale farming usually favours disease transmission due to uncontrolled home slaughter with unsafe offal disposal and generally unhygienic conditions. Therefore, any changes in animal production systems and the introduction of new animal genotypes is likely to have an impact on parasite transmission and public health, which has to be taken into account when evaluating the local acceptance and sustainability of such systems. In a first phase of this project, prevalence surveys of various parasite species in livestock (pigs, cattle, buffaloes, goats) will be carried out in an area of Son La Province, which includes different types of animal husbandry. (abridged text)
Objective: - To better understand the pathophysiology of invasive amebiasis through analysing the host-parasite interrelation in human infections of the intestinal parasite Entamoeba histolytica at the molecular, clinical and epidemiological level. General Information: - Monoclonal antibodies selectively recognizing only cysts of pathogenic Entamoeba histolytica or non-pathogenic Entamoeba dispar are developed; - Antigens recognized by monoclonal antibodies are examined in order to assess their location and functional significance; - Entamoeba histolytica and Entamoeba dispar are detected and differentiated using an improved colorimetric polymerase chain reaction method directly from faecal samples; - Cell surface molecules of pathogenic E. histolytica and nonpathogenic E. dispar and their relation to virulence are examined; - Epidemiologic studies are under way in Diyarbakir/Turkey and in Cairo/Egypt in order to assess the prevalence of E. histolytica infections. Achievements: - Monoclonal antibodies were produced that specifically recognise native and fixed cysts of E. histolytica as well as against native and fixed cysts of E. dispar. Serological studies have shown that E. dispar itself can elicit a specific serum antibody response. An improved method based on the PCR-SHELA technique has been developed to identify E. histolytica and E. dispar in human faeces. This method is suitable for use with large numbers of specimens. - The prevalences of E. histolytica and E. dispar were determined separately in Eastern Turkey using stool microscopy, PCR and serological methods. According to PCR classification the prevalence of E. dispar was 13 per cent whereas not a single case of E. histolytica was detected. Anti-E. histolytica serum antibodies were found in 0.6 per cent of the population using an ELISA with a recombinant antigen. It is concluded that the prevalence of E. dispar in the Diyarbakir area is high but that the prevalence of E. histolytica is very low. - The presence of gene of cysteine proteinase 1 (ACP1) in non pathogenic E. dispar strains was demonstrated. - Episomal transfection and continuous expression of heterologous genes in E. dispar were achieved. This is the first report of stable expression of a foreign gene in E. dispar using upstream and downstream regulatory sequences of E. histolytica ribosomal protein L21 gene. Using solvent extraction as well as hydrophobic and anion exchange chromatography, two distinct lipid-anchored glycolipids whose composition was indicative of an LPG and a lipophosphopeptidoglyan (LPPG) were characterised. A direct correlation was observed between the relative abundance of these molecules in different amebic isolates and their virulence. A novel monoclonal antibody that reacts with the LPG of virulent strains has been cloned.
In Bio-Betrieben stellt der Befall mit parasitisch lebenden Magen-Darm-Nematoden bei weidenden Jungrindern und bei kleinen Wiederkäuern einen wesentlichen Problemfaktor für die Tiergesundheit dar. Klinische und subklinische parasitäre Erkrankungen sind daher auch von erheblicher wirtschaftlicher Relevanz. Für den Tierhalter stellt sich einerseits das Problem, den Parasitendruck auf einem vertretbaren Niveau zu halten und, andererseits, der Forderung der Bio-Richtlinien nach einer weitgehenden Reduktion des Medikamenteneinsatzes nachzukommen. Klassische komplementärmedizinische Heilmethoden wie Homöopathie und Phytotherapie brachten im Bereich der Parasitenkontrolle bisher keine umsetzbaren Resultate und auch andere Alternativen wie biologische Kontrollmaßnahmen sind kommerziell noch nicht verfügbar. Deshalb beruht die Kontrolle des Parasitenbefalls auch in biologisch bewirtschafteten Betrieben immer noch weitgehend auf der Anwendung von Entwurmungsmitteln (Anthelminthika). Diese Problematik verschärft sich durch die Resistenz einiger wirtschaftlich bedeutsamer Wurmparasiten gegen seit langem eingesetzte Anthelminthika. Die Folge ist gegenwärtig eine weitere Intensivierung des Medikamenten-Einsatzes auch auf Bio-Betrieben. Diese Situation ist mit der Philosophie des biologischen Landbaus nicht vereinbar. Auf dem derzeitigen Stand der Forschung zeichnen sich für die Weidehaltung von Rindern und kleinen Wiederkäuern unter mitteleuropäischen Verhältnissen drei Strategien zur alternativen, nicht- medikamentösen Kontrolle von Wurmparasiten ab. Es handelt sich dabei - erstens um Maßnahmen, bei denen das Weidemanagement als Instrument zur Verdünnung der Parasitenbelastung auf der Weide eingesetzt wird - zweitens um eine neue biologische Kontrollstrategie, basierend auf der Verfütterung von Sporen nematophager Pilze - drittens um den Einsatz tanninhaltiger Futterpflanzen. Die beiden erstgenannten Strategien bewirkten in Versuchen eine Reduktion des Endoparasitenbefalls; bei kleinen Wiederkäuern und bei erstsömmrigen Rindern sind für eine ausreichende Kontrolle der Magen-Darm-Würmer jedoch weitere Maßnahmen nötig. Diverse Studien (meist aus Neuseeland und Skandinavien) zeigen einen anthelminthischen Effekt verschiedener Pflanzenarten, der auf deren erhöhten Gehalt an kondensierten Tanninen zurückgeführt wird und sich gegen die adulten Parasiten im Wirtstier und, in in vitro Versuchen, auch gegen die Larvenstadien richtet. Die gezielte Nutzung derartiger Futterpflanzen hätte das Potenzial, sich zu einem tragfähigen Pfeiler eines integrierten Kontrollkonzeptes gegen Magen-Darm-Nematoden bei Wiederkäuern zu entwickeln. Kondensierte Tannine schützen zudem Futterprotein vor dem mikrobiellen Abbau im Pansen und können auf diese Weise die Proteinversorgungslage des Wiederkäuers verbessern, was sich positiv auf Wachstum, Milch- und Wollproduktion auswirken kann. Kondensierte Tannine haben auch eine schützende Wirkung gegen Blähungen bei weidenden Tieren. ...
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