Saprolegnia diclina IIIA and S. parasitica employ different infection strategies when colonizing eggs of Atlantic salmon,Salmo salar L.

Here, we address the morphological changes of eyed eggs of Atlantic salmon, Salmo salar L. infected with Saprolegnia from a commercial hatchery and after experimental infection. Eyed eggs infected with Saprolegnia spp. from 10 Atlantic salmon females were obtained. Egg pathology was investigated by light and scanning electron microscopy. Eggs from six of ten females were infected with S. parasitica, and two females had infections with S. diclina clade IIIA; two Saprolegnia isolates remained unidentified. Light microscopy showed S. diclina infection resulted in the chorion in some areas being completely destroyed, whereas eggs infected with S. parasitica had an apparently intact chorion with hyphae growing within or beneath the chorion. The same contrasting pathology was found in experimentally infected eggs. Scanning electron microscopy revealed that S. parasitica grew on the egg surface and hyphae were found penetrating the chorion of the egg, and re‐emerging on the surface away from the infection site. The two Saprolegnia species employ different infection strategies when colonizing salmon eggs. Saprolegnia diclina infection results in chorion destruction, while S. parasitica penetrates intact chorion. We discuss the possibility these infection mechanisms representing a necrotrophic (S. diclina) vs. a facultative biotrophic strategy (S. parasitica).     

Rhizosphere bacterial community composition in natural stands of Carex arenaria (sand sedge) is determined by bulk soil community composition

The relative importance of specific plant properties versus soil characteristics in shaping the bacterial community structure of the rhizosphere is a topic of considerable debate. Here, we report the results of a study on the bacterial composition of the rhizosphere of the wild plant Carex arenaria (sand sedge) growing at 10 natural sites in The Netherlands. The soil properties of the sandy soils at these sites were highly disparate, most notably in pH, chloride and organic matter content. Rhizosphere and bulk soil bacterial communities were examined by culture-independent means, namely, 16S rDNA-directed PCR-DGGE profiling. Large differences were observed between the bacterial communities of the different sites for both bulk and rhizosphere soil. Cluster analysis of bacterial profiles revealed that the rhizosphere community of each site was generally more closely related to the bulk soil community of that site rather than to rhizosphere communities of other sites. Hence, bacterial community structure within the rhizosphere of C. arenaria appeared to be determined to a large extent by the bulk soil community composition. This conclusion was supported by a reciprocal planting experiment, where C. arenaria shoots of different sites yielded highly similar rhizosphere communities when planted in the same soil.     

Vertical head and trunk movement adaptations of sound horses trotting in a circle on a hard surface

Trotting a horse in circles is a standard and important part of the subjective equine lameness examination, yet objective data on this form of locomotion are sparse. The aim of this study was to investigate the effect of trotting in a circle on head and trunk movement symmetry. Vertical movements of the head, withers, os sacrum and left and right tuber coxae were measured using inertial sensors as 12 sound horses were trotted on a hard surface in a straight line and in a circle on both reins. Seven asymmetry measures and hip hike were calculated for each horse for at least nine strides of comparable stride duration across the three conditions (deviation on horse level ≤3.7% stride duration). Trotting in a circle introduced systematic changes to the movement pattern of all five body landmarks, affecting most asymmetry measures. On average the asymmetry magnitude was comparable for midline locations between reins and for the tuber coxae on opposite reins with few exceptions, although individual horses showed unsystematic differences between the two reins. The results from this study showed that the thresholds for objective discrimination between lame and non-lame horses will need adjustment on the circle due to the observed asymmetry bias.     

Expression of late viral proteins is restricted in nasal mucosal leucocytes but not in epithelial cells during early-stage equine herpes virus-1 infection

Equine herpes virus (EHV)-1 replicates in the epithelial cells of the upper respiratory tract and reaches the lamina propria and bloodstream in infected mononuclear cells. This study evaluated expression of the late viral proteins gB, gC, gD and gM in respiratory epithelial and mononuclear cells using: (1) epithelial-like rabbit kidney cells and peripheral blood mononuclear cells infected with EHV-1 in vitro; (2) an equine ex vivo nasal explant system; and (3) nasal mucosa tissue of ponies infected in vivo. The viral proteins were expressed in all late-infected epithelial cells, whereas expression was not observed in infected leucocytes where proteins gB and gM were expressed in 60-90%, and proteins gC and gD in only 20% of infected cells, respectively. The results indicate that expression of these viral proteins during early-stage EHV-1 infection is highly dependent on the cell type infected.     

Effects of meloxicam and flunixin on pain, stress and discomfort in male piglets during and after surgical castration

Surgical castration of young male piglets is now a generally accepted cause of serious distress and impairment of animal welfare. Awareness of this problem has created the moral commitment to seek for practical and more humane alternatives. As one possible alternative, the application of analgesics has been installed in Germany as an interim solution by the QS system, thus mandatory for the majority of German pig producers.Two analgesics have been authorised for this purpose. Both have been shown a significant positive impact on cortisol levels if administered pre-operatively. However, their effects on pain, stress and discomfort during castration, and on the post-castration period are conflicting. Thus, the aim of the present study was to compare the effects of Meloxicam and Flunixin on cortisol levels, behavioural indices, vocalisation, and wound healing of surgical castrated piglets in the field. There was no difference in vocalisation during castration in analgesic treated and untreated piglets. Piglets castrated under analgesia still had significantly elevated serum cortisol levels 30 min post castration, when compared to the sham castrated group. Both analgesics led to a significant impairment of behavioural indices and wound healing. It is concluded that analgesics can improve the welfare of piglets during the first part of the post-castration period. However, the benefits may be considered small and may not meet the requirements of the EU. Hence it is of high importance to prevent the interim practice of surgical castration of male piglets under analgesics from becoming implemented as a permanent condition in pig production.     

Identification of steviol glucuronide in human urine

Stevioside (250 mg capsules) was given three times daily to 10 healthy subjects. Steviol glucuronide (steviol 19-O-beta-D-glucopyranosiduronic acid; MM, 494.58; melting point, 198-199 degrees C) was characterized in the 24 h urine as the only excretion product of oral stevioside by MS, NMR, IR, and UV spectroscopy. This is the first report on the unambiguous identification of steviol glucuronide in human urine.