Detection of residues of the coccidiostat diclazuril in poultry tissues by liquid chromatography-tandem mass spectrometry after withdrawal of medicated feed

A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the quantitative determination of diclazuril in poultry tissues and feed is presented. A simple clean up with an organic solvent was carried out. A reversed-phase C(18) column was used for the high-performance liquid chromatography (HPLC) to separate the analyte with a gradient of acetonitrile and water as mobile phase. The precursor ions produced by electrospray negative ionization were selected for collisional dissociation. Validation of the methods was performed based on Commission Decision 2002/657/EC (Off. J. Eur. Communities 2002, L221, 8-36). For the detection of diclazuril in poultry meat, the decision limit was found to be 0.5 microg/kg. An animal experiment was set up in which 70 chickens were held for 6 weeks. From day 22 until day 32, they were fed feed containing 730 microg/kg diclazuril. From day 33 until day 42, every day six chickens were slaughtered, and breast, thigh, and liver were analyzed. Average steady-state concentrations of 94, 135, and 722 microg/kg in breast, thigh, and liver were obtained, respectively. Nine days after withdrawal of the medicated feed, diclazuril was still present in the different sample types.     

Cells, cytokines and other molecules associated with rejection of gastrointestinal nematode parasites

Infections with gastrointestinal nematodes represent a major problem for human health and animal health and production. The physical size of the parasite, its changing life-cycle stages and the relative inaccessibility to host cells pose unique challenges to the immune system, which has evolved specialized strategies for parasite control. This paper reviews the work performed in the authors' laboratories to identify components that are involved in the natural rejection response against ruminant gastrointestinal nematode parasites, in particular Haemonchus contortus in sheep. The results of these studies indicate that stage-specific antibodies act in concert with effector cells, in particular globular leukocytes (intraepithelial mast cells) and eosinophils, appropriately activated/primed by type 2 (T2) cytokines, to initiate different mechanisms of parasite expulsion and killing. In addition, other molecules, in particular carbohydrate binding galectins, may be involved in strengthening the final effector phase of the rejection response.     

An electron microscopic study of intra-erythrocytic stages of Babesia bovis in the brain capillaries of infected splenectomized calves.

Splenectomized vaccine donor calves undergoing primary reactions to Babesia bovis infections may develop cerebral babesiosis which leads to death if not treated in time. A brain biopsy was performed on an artificially-infected animal showing nervous symptoms and the tissue was immediately processed for electron microscopic examination. Virtually every erythrocyte in the brain capillaries sectioned was infected with B. bovis. Intra-erythrocytic merozoites, trophozoites and dividing trophozoites were indentified. Important features of the piriform merozoites included a reduced apical complex consisting of the anterior polar ring, microtubules, rhoptries and micronemes. Unidentified membrane-bound bodies, mostly spherical in shape, were observed anterior to the nucleus. The trophozoites showed very little structural differentiation and no food vacuoles or micropores could be detected. Each trophozoite produced 2 identical merozoites and the parent cell became totally incorporated in the daughter merozoites in the multiplication process. Projections were seen radiating from the surface of infected erythrocytes which appeared to adhere to other surfaces on contact. This probably resulted in the sludging of infected erythrocytes in the capillaries. The latter observations coincide with those described for Babesia argentina.     

Do citizens and farmers interpret the concept of farm animal welfare differently?

Animal welfare is of increasing importance in livestock production and consumption debates. However, discordance exists between citizens' and farmers' perception of animal welfare. Since the search for, and the realization of improvements towards farm animal welfare is strongly driven by citizen expectations, it is of utmost importance to better understand this perceptual discordance. A quantitative study was done in Flanders, Belgium during 2006, including citizens as well as farmers, to obtain a detailed insight in the way the multi-dimensional concept of farm animal welfare is valued. This allowed to discriminate between issues of agreement and disagreement. In general, a similar interpretation of farm animal welfare in terms of animal welfare related aspect's ranking was found. Differences were mainly related to aspects dealing with the ability to engage in natural behaviour on the one hand and with production process-related aspects on the other hand. Citizens evaluate the current state of animal welfare as rather problematic, while farmers report a more satisfactory evaluation of the present condition of farm animal welfare. Especially differing opinions regarding the ability to engage in natural behaviour, together with aspects related to pain, stress and the availability of space seem to contribute to the discordance between farmers and citizens in terms of evaluative beliefs.     

The possibility of positive selection for both F18(+)Escherichia coli and stress resistant pigs opens new perspectives for pig breeding

F18(+)Escherichia coli infections causing post-weaning diarrhoea and/or oedema disease are a major cause of economic losses in pig industry. To date, no preventive strategy can protect pigs from F18(+)E. coli infections. One of the most attractive approaches to eliminate F18(+)E. coli infections is the selection for pigs that are resistant to F18(+)E. coli infections. However, this strategy was not believed to be favourable because of reports of genetic association with the stress-susceptibility gene in the Swiss Landrace. To investigate this potential association more thoroughly, 131 randomly selected Belgian hybrid pigs were genotyped for both the F18(+)E. coli resistance alleles (FUT1(A)) and the stress-susceptibility alleles (RYR1(T)) and their association was investigated by determining the linkage disequilibrium. This linkage disequilibrium (LD=-0.0149) is close to zero and does not differ significantly from 0 (likelihood ratio test chi(1)(2)=1.123, P=0.29), demonstrating no association between the FUT1(A) and RYR1(T) alleles. Furthermore, only a small fraction (4.6%) of the Belgian pigs was found to be resistant to F18(+)E. coli infections. Our results suggest that selection for F18(+)E. coli resistant pigs might be an attractive approach to prevent pigs from F18(+)E. coli infections, unlike to what has previously been postulated.     

A universal microarray detection method for identification of multiple Phytophthora spp. using padlock probes

The genus Phytophthora consists of many species that cause important diseases in ornamental, agronomic, and forest ecosystems worldwide. Molecular methods have been developed for detection and identification of one or several species of Phytophthora in single or multiplex reactions. In this article, we describe a padlock probe (PLP)-based multiplex method of detection and identification for many Phytophthora spp. simultaneously. A generic TaqMan polymerase chain reaction assay, which detects all known Phytophthora spp., is conducted first, followed by a species-specific PLP ligation. A 96-well-based microarray platform with colorimetric readout is used to detect and identify the different Phytophthora spp. PLPs are long oligonucleotides containing target complementary sequence regions at both their 5' and 3' ends which can be ligated on the target into a circular molecule. The ligation is point mutation specific; therefore, closely related sequences can be differentiated. This circular molecule can then be detected on a microarray. We developed 23 PLPs to economically important Phytophthora spp. based upon internal transcribed spacer-1 sequence differences between individual Phytophthora spp. Tests on genomic DNA of many Phytophthora isolates and DNA from environmental samples showed the specificity and utility of PLPs for Phytophthora diagnostics.     

Acid-induced cold gelation of globular proteins: effects of protein aggregate characteristics and disulfide bonding on rheological properties

The process of cold gelation of ovalbumin and the properties of the resulting cold-set gels were compared to those of whey protein isolate. Under the chosen heating conditions, most protein was organized in aggregates. For both protein preparations, the aggregates consisted of covalently linked monomers. Both types of protein aggregates had comparable numbers of thiol groups exposed at their surfaces but had clearly different shapes. During acid-induced gelation, the characteristic ordering caused by the repulsive character disappeared and was replaced by a random distribution. This process did not depend on aggregate characteristics and probably applies to any type of protein aggregate. Covalent bonds are the main determinants of the gel hardness. The formation of additional disulfide bonds during gelation depended on the number and accessibility of thiol groups and disulfide bonds in the molecule and was found to clearly differ between the proteins studied. However, upon blocking of the thiol groups, long fibrillar structures of ovalbumin contribute significantly to gel hardness, demonstrating the importance of aggregate shape.     

Observation of pulsed gamma-rays above 25 GeV from the Crab pulsar with MAGIC

One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar's spectrum would shed light on this question. By developing a new electronic trigger, we lowered the threshold of the Major Atmospheric gamma-ray Imaging Cherenkov (MAGIC) telescope to 25 giga-electron volts. In this configuration, we detected pulsed gamma-rays from the Crab pulsar that were greater than 25 giga-electron volts, revealing a relatively high cutoff energy in the phase-averaged spectrum. This indicates that the emission occurs far out in the magnetosphere, hence excluding the polar-cap scenario as a possible explanation of our measurement. The high cutoff energy also challenges the slot-gap scenario.     

Innate and adaptive resistance of Indonesian Thin Tail sheep to liver fluke: a comparative analysis of Fasciola gigantica and Fasciola hepatica infection

In the current study, three independent trials directly compared Fasciola gigantica and Fasciola hepatica infection of ITT sheep. In all trials, F. hepatica infection resulted in higher worm burden recoveries and greater physiological damage to ITT sheep. Developmental differences of the two Fasciola species were also observed during the first twelve weeks of a primary infection, where the migration and growth of F. hepatica was more rapid than F. gigantica. Various immunological blood parameters were measured and indicated similar kinetics in the humoral and cellular responses during the time course of infection with each Fasciola species. In contrast to F. hepatica infection, we demonstrate an innate and adaptive comparative ability of ITT sheep to resist the early stages of infection with F. gigantica infection. Unraveling the mechanisms leading to this differential resistance may potentially lead to new methods for the control of fasciolosis and other human liver flukes.     

Heating and cooling rates and their effects upon heart rate in the angulate tortoise,Chersina angulate

The heating and cooling rates of adult Chersina angulata were investigated to ascertain whether these tortoises can physiologically alter their rates of heat exchange. In addition, heart rates were recorded to provide an insight into the control of heat exchange. C. angulata heats significantly faster than it cools. Heart rates increase with increasing body temperature, and for all body temperatures heart rates were greater during heating than during cooling. This suggests that the cardiovascular system plays a role in the heat exchange of the tortoises, but further study is required to completely understand the thermoregulatory process.