The effect of dietary immunostimulants on the susceptibility of common carp (Cyprinus carpio) to the white spot parasite, Ichthyophthirius multifiliis

One of the main obstacles in freshwater aquaculture is the parasitic ciliate Ichthyophthirius multifiliis (Ich), the causative agent of white spot disease. The use of immunostimulants as feed additives may be a promising approach to control Ich infection. In the present study, we tested the prophylactic effect of orally administered β-1,3/1,6-glucan and propolis extract E50 against Ich infection in common carp. In total, 122 fish were separated into three experimental groups fed with a control, 3% β-glucan and 1% propolis diet for 40 consecutive days, respectively. On day 40, 16 fish per group were individually exposed to Ich theronts and the number of trophonts was counted 5 days post exposure. Relative gene expression of interleukin 1-β (IL-1-β) in common carp liver was examined by qPCR. Compared to control, the mean infection intensity was lower in the β-glucan- and propolis-fed groups; however, the difference was not statistically significant. The relative expression of IL-1-β significantly decreased in the propolis-fed group at day 10. In the β-glucan-fed group, a significant IL-1-β decrease was detected at day 15 compared to control. Although the Ich infection intensity was slightly decreased in both treated groups, and IL-1-β was moderately down-regulated in the liver of common carp, our results suggest that the applied feeding regime is insufficient to prevent Ich outbreaks in common carp

Organische Düngung in der Karpfenteichwirtschaft: Fischertrag und Umweltaspekte

Dieses Mesokosmenexperiment befasst sich mit verschiedenen Maßnahmen zur Steigerung der Naturnahrung in Teichen unter Nutzung natürlicher Ressourcen. Das Ziel war, Naturertrag, Nachhaltigkeit und Produktqualität in der Karpfenteichwirtschaft zu verbessern. Durch organische Düngung mit Pferde- und Hühnermist (3t/ha) konnte in Teichen mit nährstoffärmeren Teichböden (P2O5-CAL 13,4 mg/100 g Boden) die Nährtierdichte erhöht und der Fischertrag durchschnittlich um etwa 200 kg/ha gesteigert werden. Zudem hatte die organische Düngung am Ende der Produktionsperiode keinen signifikanten Einfluss auf die Wasser- und Bodenqualitätsparameter

TBVAC2020 : advancing tuberculosis vaccines from discovery to clinical development

TBVAC2020 is a research project supported by the Horizon 2020 program of the European Commission (EC). It aims at the discovery and development of novel tuberculosis (TB) vaccines from preclinical research projects to early clinical assessment. The project builds on previous collaborations from 1998 onwards funded through the EC framework programs FP5, FP6, and FP7. It has succeeded in attracting new partners from outstanding laboratories from all over the world, now totaling 40 institutions. Next to the development of novel vaccines, TB biomarker development is also considered an important asset to facilitate rational vaccine selection and development. In addition, TBVAC2020 offers portfolio management that provides selection criteria for entry, gating, and priority settings of novel vaccines at an early developmental stage. The TBVAC2020 consortium coordinated by TBVI facilitates collaboration and early data sharing between partners with the common aim of working toward the development of an effective TB vaccine. Close links with funders and other consortia with shared interests further contribute to this goal

TBVAC2020: Advancing tuberculosis vaccines from discovery to clinical development

TBVAC2020 is a research project supported by the Horizon 2020 program of the European Commission (EC). It aims at the discovery and development of novel tuberculosis (TB) vaccines from preclinical research projects to early clinical assessment. The project builds on previous collaborations from 1998 onwards funded through the EC framework programs FP5, FP6, and FP7. It has succeeded in attracting new partners from outstanding laboratories from all over the world, now totaling 40 institutions. Next to the development of novel vaccines, TB biomarker development is also considered an important asset to facilitate rational vaccine selection and development. In addition, TBVAC2020 offers portfolio management that provides selection criteria for entry, gating, and priority settings of novel vaccines at an early developmental stage. The TBVAC2020 consortium coordinated by TBVI facilitates collaboration and early data sharing between partners with the common aim of working toward the development of an effective TB vaccine. Close links with funders and other consortia with shared interests further contribute to this goal

Polar filament discharge of Myxobolus cerebralis actinospores is triggered by combined non-specific mechanical and chemical cues

This study presents initial evidence for the requirement of both chemical and mechanical stimuli to discharge polar capsules of Myxobolus cerebralis actinospores, the causative agent of salmonid whirling disease. The obligate need for combined discharge triggers was concluded from data obtained in a before/after experimental set-up carried out with individual locally immobilized actinospores. Homogenized rainbow trout mucus as chemostimulus and tangency of the apical region of the spores to achieve mechanical stimulation were applied subsequently. The actinospores showed discharged polar filaments exclusively when mucus substrate application was followed by touching the polar capsule-bearing region, but not when either stimulus was offered solely to the same individuals. We measured filament discharge rates to mucus preparations in a microscopic assay using supplementary vibration stimuli to ensure mechanical excitation. The actinospores responded similarly to different frequencies, which suggested a touch-sensitive recognition mechanism. Discharge specificity for salmonid mucus could not be confirmed, as mucus of common carp and bream could trigger similar filament expulsion rates. To a lesser extent homogenized frog epidermis and bovine submaxillary mucin could also stimulate the attachment reaction. In contrast, mucus of a pulmonate freshwater snail elicited no response

Myxozoan transmission via actinospores: new insights into mechanisms and adaptations for host invasion

Various mechanisms that enable and improve transmission success of myxozoan actinospore stages towards fish hosts are described, based upon a combination of experimental data and functional analysis of morphological characters. For this purpose, laboratory-reared actinospores of Myxobolus cerebralis, Myxobolus parviformis, Henneguya nuesslini and Myxobolus pseudodispar were employed to exemplarily investigate aspects of host attachment and invasion. The process of polar filament discharge of M. cerebralis actinospores was analysed, showing that full discharge occurs in less than 10 msec. Additionally, a mechanism that rapidly contracts the discharged filament after discharge is described for the first time. Its purpose is most likely to bring the actinospore apex rapidly into intimate contact with the surface of the host. Unlike M. cerebralis, M. parviformis actinospores did not discharge polar filaments after mechanical and chemical stimulation, suggesting a different mode of triggering. For H. nuesslini actinospores, experimental results indicated that polar filament discharge is independent of external calcium-ion concentration but is influenced by osmolality. After attachment of an actinospore and prior to penetration into the host, an ensheathed unit (‘endospore’), containing the sporoplasm, was emitted from the valves in a manner which varied from species to species. Experimentally induced sporoplasm emission was time-dependent and was found to be independent of polar filament discharge in H. nuesslini. Remarkably, it could be concluded that the sporoplasm is able to recognize host-stimuli while still within the intact spore. An updated summary of the sequential course of events during host recognition and invasion by actinospores is given

Entwicklung alternativer, ökologisch unbedenklicher, effektiver und für Fische gut verträglicher Bekämpfungsstrategien gegen den Ziliaten Ichthyophthirius multifiliis ohne Einsatz von Therapeutika in Forellenhaltungen (Verbundvorhaben)

Im Rahmen des Projekts AbiAqua konnten neue alternative Strategien zur Bekämpfung der Ichthyophthiriose entwickelt werden. Zum einen wurden Methoden der Transmissionsunterbrechung erfolgreich durchgeführt, zum anderen erwiesen sich zwei Impfstrategien als sehr vielversprechend. Erstmalig konnten chemischen Stimuli identifiziert werden, die infektiöse Ichthyophthirius multifiliis Theronten zur Wirtsfindung und Wirtserkennung nutzen. Die spezifischen Reaktionen ließen sich dazu nutzen, die Schwärmer mittels natürlicher Substanzen zu ungerichtetem Wirtsfindeverhalten zu stimulieren und sie über deren Erkennungsreaktionen in Wirtsnähe an Oberflächen abzufangen. Daneben konnte mittels andauernder Aktivierung und dem damit erhöhten Energieverbrauch der Erregerstadien das Zeitfenster, in dem diese einen neuen Wirt aufgesucht haben müssen, entscheidend verkürzt und die Wirtsinvasion quantitativ minimiert werden. I. multifiliis Schwärmer zeigten nach Zugabe von Aktivierungskomponenten ins Wasser eine verminderte Fähigkeit zur Wirtserkennung. Eine signifikant erhöhte Mortalität der Transmissionsstadien konnte dabei sowohl durch Zugabe von Reinsubstanzen als auch durch Abfangen auf speziellen Fallen-Prototypen erzielt werden. Vom Fisch abgehende Stadien konnten zudem durch Abfangmatten wirkungsvoll entfernt werden. Die Impfung über eine Tauchbadvakzine mit formalininaktivierten I. multifiliis nach Vorbehandlung der Fische in einem Ultraschallbad und die Impfung durch eine intraperitoneale Injektion formalininaktivierter I. multifiliis erwiesen sich als wirksam. Es konnte demnach ein System entwickelt werden, das die Aufnahme des Impfstoffes über die Haut verbessert und so zu signifikant besseren Impferfolgen führt. Die im Rahmen dieses Projektes entwickelten neuartigen Ansätze bieten klare Vorteile gegenüber der direkten Anwendung von Desinfektionsmitteln und Therapeutika in der Speisefischproduktion. Sie sind ökologisch unbedenklich, ökonomisch für den Teichwirt und einfach in der Handhabung. Durch die Entwicklung neuer Ansätze zur Eindämmung der wichtigsten Parasitose in der Aquakultur konnte ein wertvoller Beitrag zum Ausbau der ökologischen Produktion in Deutschland und zu einer Stärkung des Tierwohls in der Fischzucht geleistet werden