The fatty acid composition of Nereis diversicolor cultured in an integrated recirculated system: Possible implications for aquaculture

The potential of solid waste originating from a recirculated fish culture system, i.e. faecal material, uneaten food pellets and bacterial biofilms was examined as food source for the marine polychaete Nereis diversicolor. These polychaetes could be a valuable food for fish if they provide essential fatty acids to the fish. Therefore, we analysed the fatty acid profiles from feed and faecal materials, the sediment as well as the cultured organisms — fish and several batches of N. diversicolor — from an integrated recirculating aquaculture system.The major fatty acids (saturated, monounsaturated and polyunsaturated) for all analysed fish feed, fish and faeces samples were C16:0, C18:1 and C22:6 (n − 3), accounting for 48% to 57% of the fatty acids in the samples. The major fatty acids within the sediment were C16:0, C18:1 and C18:3 (n − 3), accounting for 61% of the total fatty acids. The samples of N. diversicolor revealed C16:0, C18:1 and C20:5 (n − 3) as the major fatty acids. Combined, they accounted for 56% of the total fatty acids detected within the worm samples.The results indicate that a recycling or even an upgrade of excreted feed nutrients such as fatty acids, which were otherwise discharged, can be achieved through integrated aquaculture combining fish and worm culture.     

Evolution and host variation of the canine parvovirus: molecular basis for the development of a new virus

Canine parvovirus (CPV) evolved as a new pathogen in dogs between 1976 and 1978 from feline panleukopenia virus (FPV). The new virus hit an unprotected population, caused a dramatic pandemic and infected virtually all populations of domestic and wild carnivores worldwide. The great similarity between the two viruses and their differences in host range, both in vivo as well as in vitro, make it a good model system for emerging diseases and host range shifts of viruses. Recent results showed that CPV expanded its host range by binding to the canine transferrin receptor (Tfr). Residues in the capsid protein that had been defined as host range controlling regions also control the binding to the canine transferrin receptor. These residues are located on a raised region of the capsid at the three-fold axis of symmetry. Interestingly, adaption of the new virus to the new host appears to correlate with an improved binding to the Tfr receptor.     

Antibody response after immunization with a Salmonella Typhimurium live vaccine in dependence on the way of application

In Germany now, the recognition of Salmonella infections in pig herds is based on three different commercial tests detecting antibodies against Salmonella-derived lipopolysaccharide (LPS). However, a serious disadvantage of these tests, used so far, is the restricted detection of antibodies belonging predominantly to the immunoglobulin class g (IgG). Therefore, a new test was developed to detect three Ig classes (IgM, IgG and IgA). Different constellations between the three Ig classes allow the evaluation of the current infection status of each pig. Under field conditions, this was proved in three different vaccination trials using a commercial Salmonella Typhimurium live vaccine.     

Genotyping of groups of cows to improve genomic breeding values of new traits

Genotyping females and including them into the reference set for genomic predictions in dairy cattle is considered to provide gains in reliabilities of estimated breeding values for selection candidates. This should especially be true for low heritability traits. By the use of simulation, we extended a genomic reference set for an existing trait by including a fixed number of genotyped first‐crop daughters for one or two generations of reference sires. Moreover, we calculated results for the effects of a similar strategy in a situation where for a new trait the recording of phenotypes has recently started. For this case, we compared the effect of two different genotyping strategies: first, to phenotype cows but to genotype their sires only, and second, to collect phenotypes and genotypes on the same cows. We studied the effects on validation reliabilities and unbiasedness of predicted values for selection candidates. We found that by extending the reference set with genotyped daughters it is possible to increase the validation reliability of genomic breeding values. In the case of a new trait, it is always better to collect and use genotypes and phenotypes on the same animals instead of using only sire genotypes. We found that the benefits that can be achieved are sensitive to the sampling strategy used when selecting females for genotyping.     

Analyzing organic matter composition at intact biopore and crack surfaces by combining DRIFT spectroscopy and Pyrolysis‐Field Ionization Mass Spectrometry#

In the clay‐illuvial horizons (Bt) of Luvisols, surfaces of biopores and aggregates can be enriched in clay and organic matter (OM), relative to the bulk of the soil matrix. The OM composition of these coatings determines their bio‐physico‐chemical properties and is relevant for transport and transformation processes but is largely unknown at the molecular scale. The objective of this study was to improve the interpretation of spectra from Fourier transform infrared spectroscopy in diffuse reflectance mode (DRIFT) by using thermograms and released ion intensities obtained with pyrolysis‐field ionization mass spectrometry (Py‐FIMS) for a more detailed analysis of the mm‐scale spatial distribution of OM components at intact structural surfaces. Samples were separated from earthworm burrow walls, crack coatings, uncoated cracks, root channels, and pinhole fillings of the Bt‐horizons of Luvisols. The information from Py‐FI mass spectra enabled the assignment of OM functional groups also from spectral regions of overlapping DRIFT signal intensities to specific OM compound classes. In particular, bands from C=O and C=C bonds in the infrared range of wave numbers between 1,641 and 1,605 cm^?1 were related to heterocyclic N‐compounds, benzonitrile, and naphthalene. The OM at earthworm burrow walls was composed of chemically labile aliphatic C‐rich and rather stable lignin and alkylaromatic compounds whereas the OM of thick crack coatings and pinholes was dominated by heterocyclic N and nitriles and high‐molecular compounds, likely originating from combustion residues. In combination with Py‐FIMS, DRIFT applications to intact samples seem promising for generating a more detailed mm‐scale spatial distribution of OM‐related sorption and wettability properties of crack and biopore surfaces that may serve as preferential flow paths in structured soils.     

DanTox—a novel joint research project using zebrafish (Danio rerio) to identify specific toxicity and molecular modes of action of sediment-bound pollutants

Introduction

The European Water Framework Directive aims to achieve a good ecological and chemical status in surface water of European rivers by the year 2015. Since sediments and particulate matter act as secondary sources for pollutants, applied sediment toxicology is perceived to play a major role for obtaining new knowledge that can contribute to successful attainment of the goal. However, the existing bioassays for sediment toxicity analyses do not provide sufficient data concerning bioavailability of environmental pollutants. In this regard, there is an urgent need to combine sediment contact assays with gene expression analysis to investigate mechanism-specific sediment toxicity.

Purpose

The aim of the novel joint research project is to develop a eukaryotic test system, which can be used to investigate the ecotoxicological effects of contaminated sediments on gene expression level (DNA-array and RT-PCR). Current ecotoxicological research customarily involves a battery of bioassays to cover different toxicological endpoints (e.g., teratogenicity, genotoxicity, mutagenicity, Ah-receptor-mediated toxicity, neurotoxicity). In contrast, methods that detect alterations in gene expression offer deeper insight by elucidating how chemical exposure and/or environmental challenge affect multiple metabolic pathways leading to these particular kinds of toxic response. Gene expression profiles reflect the way cells and organisms adapt or respond to a changing environment.

Conclusion

The present project aspires to increase the fundamental molecular and physiological knowledge concerning the mode of action of environmental toxicants in zebrafish (Danio rerio). By working with partners from the academic and research institutions as well as from industry and waterway regulations, the success of this basic research-driven joint project in terms of development and implementation of novel sediment toxicity methods will be realized.     

The bacteriological and serological prevalence of Campylobacter spp. and Yersinia enterocolitica in fattening pig herds in Lower Saxony

This article presents the results of a study on the occurrence of two bacteria that cause zoonoses, Campylobacter spp. and Yersinia enterocolitica. The study was carried out in 30 fattening herds in Lower Saxony, Germany, in 2004 and compares the results of bacteriological and serological methods of detection. Bacteriological findings of Campylobacter spp. in the faeces indicated that 69.7% of the fattening pigs were positive, but 81.2% tested positive serologically. All herds tested here were both bacteriologically and serologically positive for Campylobacter spp. Furthermore, only 8.4% tested positive for Yersinia enterocolitica in the faecal samples, but 66.8% of the animals were serologically positive for that bacterium. While bacteriological examination did not detect Yersinia enterocolitica in 56.7% of the herds tested, serological testing showed that only 16.7% of the units were without reacting animals. The great difference between the results of bacteriological and serological testing, especially in the case of Yersinia enterocolitica, can be explained by the intermittent intestinal excretion and predominance of this bacterium in the animals' tonsils. Low faecal excretion is also the reason for the low detection rate of 3.4% of Yersinia enterocolitica in the environmental samples, while that of Campylobacter spp. was 33.3%. These results indicate that the environment plays only a secondary role in the distribution of Yersinia enterocolitica in pig herds.