1,720,984 research outputs found
Differential effects of acute eustress and distress on gene regulation patterns in the carp (Cyprinus carpio L.) brain
Get PDFThe activities of certain genes as a consequence of exposure to stressors related to typical handling procedures in aquaculture have not been studied in sufficient detail in fish. A stress trial with koi carp was, therefore, conducted, aiming at identifying relevant gene expression patterns in different brain regions during stress responses. The following stressors were selected: tank manipulation, distress caused by exposure to air and eustress due to feed rewards. Responses to these stressors were evaluated 10, 30 and 60 min after their application. The exact determination of gene expression profiles in the carp brain required the comparison of several suitable reference genes, which is also highly recommended for other studies focusing on the fish brain. Moreover, and as expected, the mRNA expression of a number of early immediate genes indicated activity in different brain regions as a response to changes in rearing and experimental conditions. In addition, the mRNA expression of metabolic genes was investigated, since increased brain activity may also increase the metabolic demands of certain brain areas. Furthermore, genes related to the stress axis were included in the study. The mRNA expression patterns of genes belonging to the stress axis revealed that negative stress caused by exposure to air had broad- ranging effects on the gene regulation patterns in the fish brain, even if the fish were only treated for 1 min. This parallels the effects that have been observed on blood cortisol and glucose. In contrast, a limited number of genes allows discrimination of eustress and distress, which indicates that further research is needed in the future. Finally, the use of different control groups is highly recommended for fish experiments to correct for typical experimental procedures such as lid openings or social isolation
Effects of different acute stressors on the regulation of appetite genes in the carp (Cyprinus carpio L.) brain
Get PDFOur understanding of the timing of stress responses and specific roles of different regulatory pathways that drive stress responses is incomplete. In particular, the regulation of appetite genes as a consequence of exposure to different stressors has not been studied in sufficient detail in fish. Therefore, a stress trial was conducted with koi carp, aiming at identifying typical effects of stress on regulation of appetite genes. The stressors tank manipulation, air exposure and feed rewarding were chosen. The responses to these stressors were evaluated 10, 30 and 60 min after the stressors were applied. Orexigenic and anorexigenic genes were investigated in four different brain regions (telencephalon, hypothalamus, optic tectum and rhombencephalon). The results show that, apart from the typical appetite regulation in the hypothalamus, the different brain regions also display pronounced responses of appetite genes to the different stressors. In addition, several genes in the serotonergic, dopaminergic and gaba-related pathways were investigated. These genes revealed that rearing in pairs of two and opening of the tank lid affected anorexigenic genes, such as cart and cck, which were not changed by air exposure or feed rewarding. Moreover, distress and eustress led to limited, but distinguishable gene expression pattern changes in the investigated brain regions
Preliminary investigation of an idiopathic muscle disease in farmed burbot Lota lota
No full textThe rearing of less established fish species in recirculating aquaculture systems (RASs) is increasing, but may require adaptations of the rearing facilities if health impairments occur. We observed several health issues in burbot Lota lota reared for up to 2 yr in a RAS and used microbiological, histological and molecular-biological methods to identify the causative agents. Minor skin trauma led to the development of ulcers. In addition, several fillets of burbot showed pronounced granulomatous inflammation and calcification with signs of muscle fiber degeneration which resembled a condition called ‘sandy flesh disease’ in North American walleye. Several infectious agents were able to be excluded as a cause for the disease. Carnobacterium maltaromaticum was isolated in high numbers in some of the affected muscle tissue. However, the role of this bacterium or other causative agents or husbandry conditions remains to be elucidated
Multiple faces of stress in the zebrafish (Danio rerio) brain
Get PDFThe changing expressions of certain genes as a consequence of exposure to stressors has not been studied in detail in the fish brain. Therefore, a stress trial with zebrafish was conducted, aiming at identifying relevant gene regulation pathways in different regions of the brain. As acute stressors within this trial, feed rewarding, feed restriction, and air exposure have been used. The gene expression data from the experimental fish brains have been analyzed by means of principal component analyses (PCAs), whereby the individual genes have been compiled according to the regulation pathways in the brain. The results did not indicate a mutual response across the treatment and gender groups. To evaluate whether a similar sample structure belonging to a large sample size would have allowed the classification of the gene expression patterns according to the treatments, the data have been bootstrapped and used for building random forest models. These revealed a high accuracy of the classifications, but different genes in the female and male zebrafish were found to have contributed to the classification algorithms the most. These analyses showed that less than eight genes are, in most cases, sufficient for an accurate classification. Moreover, mainly genes belonging to the stress axis, to the isotocin regulation pathways, or to the serotonergic pathways had the strongest influence on the outcome of the classification models
Occurrence of fungi and fungal toxins in fish feed during storage
Get PDFPeriods of unfavorable storing conditions can lead to changes in the quality of fish feeds, as well as the development of relevant mycotoxins. In the present study, a commercial fish feed was stored under defined conditions for four weeks. The main findings indicate that even storing fish feeds under unsuitable conditions for a short duration leads to a deterioration in quality. Mycotoxin and fungal contamination were subsequently analyzed. These investigations confirmed that different storage conditions can influence the presence of fungi and mycotoxins on fish feed. Notably, ochratoxin A (OTA) was found in samples after warm (25 °C) and humid (>60% relative humidity) treatment. This confirms the importance of this compound as a typical contaminant of fish feed and reveals how fast this mycotoxin can be formed in fish feed during storage
Tagungsband der XVII. Gemeinschaftstagung der Deutschen, Österreichischen und Schweizer Sektionen der European Association of Fish Pathologists EAFP
Get PDFDie XVII Gemeinschaftstagung der Deutschen, Österreichischen und Schweizer Sektionen der European Association of Fish Pathologists (E-APF) wurde vom 2. bis zum 9. Oktober im Hotel Au Parc in Fribourg (Freiburg im Üechtland) durchgeführt. Die Tagung stand unter dem Motto «Fischgesundheit – eine Herausforderung für alle». Dieses Motto veran-schaulicht, dass das Erhalten einer guten Gesundheit bei Wassertieren von zentraler Bedeutung ist, wobei hier der Ausdruck «Fisch» sehr weit gefasst werden muss, sind doch in den Tagungsthemen nicht nur Fische, sondern auch Krebstiere enthalten. Immer wieder treten neue Krankheiten sowohl bei freilebenden als auch bei unter menschlicher Obhut gehaltenen Was-sertieren auf, was einerseits für die Wissenschaft andererseits aber auch für die Halter von solchen Tieren eine Herausforderung bedeutet. Ohne die Zusammenarbeit von Wissenschaft, Medizin, Haltung und Naturbehörden ist eine erfolgreiche Lösung solcher Probleme kaum möglich. Dabei geht es aber nicht nur um neue Probleme, sondern auch seit langem bekannte Krankheiten können immer wieder eine Herausforderung darstellen, sei es, weil erfolgreiche Therapien fehlen oder nicht mehr verfügbar sind, sei es, weil Probleme wieder neu auftreten. Dazu kommen immer wieder neue gesetzliche Vorgaben, die es zu berücksichtigen gilt, sowie neu definierte Ansprüche bezüglich Tierhaltung und Tierwohl. Mit dem breit gefächerten thematischen Angebot versuchte die Tagung, Einblicke in diese Heraus-forderungen zu geben. Dabei dienten nicht nur Vorträge und Poster der Wissensvermittlung. Ebenso wichtig waren die persönlichen Kontakte, die einen regen Austausch unter den Teilnehmenden ermöglichten
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Preliminary investigation of an idiopathic muscle disease in farmed burbot Lota lota
No full textThe rearing of less established fish species in recirculating aquaculture systems (RASs) is increasing, but may require adaptations of the rearing facilities if health impairments occur. We observed several health issues in burbot Lota lota reared for up to 2 yr in a RAS and used microbiological, histological and molecular-biological methods to identify the causative agents. Minor skin trauma led to the development of ulcers. In addition, several fillets of burbot showed pronounced granulomatous inflammation and calcification with signs of muscle fiber degeneration which resembled a condition called 'sandy flesh disease' in North American walleye. Several infectious agents were able to be excluded as a cause for the disease. Carnobacterium maltaromaticum was isolated in high numbers in some of the affected muscle tissue. However, the role of this bacterium or other causative agents or husbandry conditions remains to be elucidated
Effects of different acute stressors on the regulation of appetite genes in the carp (Cyprinus carpio L.) brain.
Get PDFOur understanding of the timing of stress responses and specific roles of different regulatory pathways that drive stress responses is incomplete. In particular, the regulation of appetite genes as a consequence of exposure to different stressors has not been studied in sufficient detail in fish. Therefore, a stress trial was conducted with koi carp, aiming at identifying typical effects of stress on regulation of appetite genes. The stressors tank manipulation, air exposure and feed rewarding were chosen. The responses to these stressors were evaluated 10, 30 and 60 min after the stressors were applied. Orexigenic and anorexigenic genes were investigated in four different brain regions (telencephalon, hypothalamus, optic tectum and rhombencephalon). The results show that, apart from the typical appetite regulation in the hypothalamus, the different brain regions also display pronounced responses of appetite genes to the different stressors. In addition, several genes in the serotonergic, dopaminergic and gaba-related pathways were investigated. These genes revealed that rearing in pairs of two and opening of the tank lid affected anorexigenic genes, such as cart and cck, which were not changed by air exposure or feed rewarding. Moreover, distress and eustress led to limited, but distinguishable gene expression pattern changes in the investigated brain regions
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