Recognition of the Nor98 variant of scrapie in the Swedish sheep population.

Within the framework of the active surveillance for transmissible spongiform encephalopathies in sheep in Sweden, 4 cases of the atypical form of scrapie, Nor98, were identified during 2003. Nor98 is a recently recognized and poorly understood variant of scrapie, first described in Norway. The cases were positive by the rapid test (enzyme-linked immunosorbent assay). Immunohistochemical staining showed diffuse thin-granular staining of the cerebellar cortex. Western immunoblotting analysis of specimens of brain stem and cerebellum showed a light band of approximately 12 kDa. Typical scrapie was ruled out based on the confirmatory testing. The affected ewes were from 4 different flocks. They were between 7 and 9 years old. Two were of the ARQ/ARQ genotype, 1 ARR/ARQ, and 1 ARR/AHQ. Two ewes had shown ataxia, and the other 2 had no clinical signs. Whole-flock slaughter was applied, and testing of the flock mates did not reveal additional cases. Nor98 differs from typical scrapie in its epidemiology, frequency of genotypes of sheep affected, clinical signs, microscopic lesions, distribution of scrapie prion protein in the brain, and characteristics of the immunostaining and immunoblotting profiles.     

Segment-based coancestry,additive relationship and genetic variance within and between the Norwegian and the Swedish Fjord horse populations

ABSTRACT

The Fjord horse originates from Norway but forms a global population due to several small populations in foreign countries. There exists no information about the additive relationship and the genetic variance between these subpopulations. By collecting blood samples from Norwegian and Swedish Fjord horses, a sample of 311 Norwegian and 102 Swedish horses gave 485,918 SNPs available for analysis. Their inbreeding coefficients were calculated and compared to the pairwise coancestry and the shared genomic segments. The effective population size was almost similar with the two methods in the Norwegian Fjord horse population (63 and 71), but very different in the Swedish population (269 and 1136) and unprecise due to a much smaller number of observations. The study showed that coancestry from shared genomic segments can be used to estimate additive genetic relationship and genetic variation within and between the global populations of the Fjord horse.     

The Influence of Organic and Integrated Production on Nutritional,Sensory and Agricultural Aspects of Vegetable Raw Materials for Food Production

In a six-year crop rotation trial organically and integrated grown vegetables were produced according to current good agricultural practices, taking quality and quantity aspects into consideration. The raw materials assessed focussed on materials used for industrial food production. Nutritional, sensory and agricultural aspects were evaluated. Carrot, cabbage, onion, pea and potato are possible to grow organically for industrial purposes. Depending on crop, the yield was lower (65-90%) for organically grown compared to integrated grown. Cultivation of organic spinach and dill turned out to be difficult due to problems with weed and discoloration. The chemical analyses included pesticide residues, nitrate, glycoalkaloid, dry matter, vitamin C and 25 different minerals and trace elements. Overall, the organically grown crops had higher dry matter content than the integrated grown. However, when examining the data for the different crops contradictory results were noted. No significant differences due to growing system were noticed for vitamin C and the other nutrients except for 4 of the trace elements. The growing system did not influence the sensory properties.     

Describing Human–Wildlife Interaction from a European Perspective

European researchers from both the natural and social sciences show growing interest in studying interactions between society and wildlife. A wealth of theoretical frameworks, concepts, and methods are used, but an integration of perspectives is lacking. This research note summarizes results from two workshops that included 63 delegates from 25 European countries, as well as a follow-up survey of 41 respondents. Two main theoretical approaches to the study of human–wildlife interactions were identified. One approach focuses on the collective societal level relying on theories of governance, social representation, deliberative procedures, and commons theory. The other approach targets individuals or groups, and is based on theories such as the cognitive hierarchy, theory of reasoned action, and theory of planned behavior. Interdisciplinary collaboration is needed to identify the best options for wildlife conservation and management in a more politically integrated Europe.     

Modelling carbon dynamics in mixed grass–red clover swards

Growth and carbon dynamics in mixed grass–red clover leys were simulated using a growth model for pure stands based on radiation use, allocation within plant and loss of biomass. The model and its parameter values were taken from previous applications of the model to pure swards of grass and red clover grown in the same experiment at the same sites and years.     

Dietary phosphorus requirement of juvenile Atlantic salmon, Salmo salar L.

The objective of this study was to determine the dietary phosphorus (P) requirement of juvenile Atlantic salmon, Salmon salar L. Triplicate groups of fish (mean initial weight 1.4 g) were fed semipurified, casein-gelatine-based diets containing one of five levels of P (4, 8, 10, 15 and 25 g kg⁻¹) from Ca(H₂PO₄)₂·H₂O, or a commercial feed (17 g kg⁻¹ P) for 9 weeks. Weight gains did not differ significantly among treatment groups fed the experimental diets but were slightly less than gains in fish fed the commercial feed. Feed efficiency (wet weight gain/dry feed consumed) was similar in all groups, averaging 1.45. Availability of dietary P, estimated from apparent retention and apparent digestibility, was 86%. Whole-body P concentrations declined in fish fed diets containing less than 10 g kg⁻¹ P. Fitting a logistic curve to dietary P vs. whole-body P concentrations indicated that a minimum of 11 g kg⁻¹ dietary P (9 g kg⁻¹ digestible P) was required by juvenile Atlantic salmon to maintain whole-body P concentrations at initial levels. Calculation of a dietary requirement using a simple factorial model which incorporated measurements of P availability, feed efficiency and normal whole-body P concentration indicated that the dietary requirement was approximately 10 g kg⁻¹. The dietary requirement established in this study (10–11 g kg⁻¹) is higher than previously reported for Atlantic salmon or other fishes. Possible reasons for the wide range of reported dietary P requirements in fishes are discussed.     

Genetic variations in survival of rohu carp (Labeo rohita, Hamilton) after Aeromonas hydrophila infection in challenge tests

A challenge test against Aeromonas hydrophila was conducted using 2062 rohu carp (Labeo rohita) fingerlings obtained from 52 dams and 87 sires (87 full-sib families) of two year-classes (2003 and 2004). Attempts to establish a cohabitant challenge model were not successful. Therefore, fish were challenged by intraperitoneal injection with A. hydrophila in two replicate tanks per year-class, and dead fish were collected hourly. The mortality reached its peak at 16–22 h after challenge and had almost completely stopped after 58 h. The test was terminated after 382 h at which the average survival was 43.9 and 48.9% in the two 2003 year-class tanks, and 77.1 and 35.8% in the two 2004 year-class tanks. Heritability estimates for survival were obtained from sire and dam threshold models (THR) and sire and dam linear repeatability models (LINR). For both types of models the heritability estimates based on data from single tanks were not consistent. For both year-classes, data from one of the two challenged tanks demonstrated significant additive genetic variation in survival during the A. hydrophila infection, whereas the heritability estimates were not significantly different from zero for the other tank. Further, genetic correlation between survivals in the two replicate tanks in each year-class was not significantly different from zero. The differential results from the replicate tanks demonstrate that additional challenge test experiments are needed before firm conclusions can be drawn about the magnitude of additive genetic variation for survival to aeromonasis in rohu carp. A cohabitant challenge model that allows the testing of important defence mechanisms in the skin and mucous membranes of the fish might have been more appropriate. To establish a valid cohabitant challenge model for rohu carp should be given high priority.     

Potato tuber sugars, starch and organic acids in relation to ozone exposure

Summary Data from two Swedish and one Finnish open-top chamber experiments were combined to investigate effects of ozone exposure on potato (Solanum tuberosum L.) tuber content of starch, sucrose, fructose, glucose, malic, citric and ascorbic acids. The glucose, fructose and malic acid concentrations showed strong negative correlations with ozone exposure, while citric acid, consistently increased with ozone exposure. No ozone effects could be demonstrated on starch, sucrose or ascorbic acid concentrations. It is discussed to what extent the changes found in potato tuber composition can be explained in terms of ozone effects on tuber maturity. Ozone exposure was expressed as the accumulated exposure over a cut-off concentration of 40 nmol mol⁻¹ (AOT40) and as the accumulated uptake of ozone over an ozone uptake rate threshold of 7 nmol m⁻² s⁻¹ (CUO 7). The difference in ability of the exposure indices to explain observed effects was small.     

Effects of seedbed properties on crop emergence: 3. Effects of firming of seedbeds with various sowing depths and water contents

Abstract

Extensive experiments were carried out in shallow plastic boxes placed directly on the ground in the field to study the effects of seedbed properties on the emergence of various crops in a cool temperate climate. In a group of experiments with barley (Hordeum vulgare L.), we studied the effects on crop emergence of firming (slight compaction) of the seedbed, simulating the recompacting effects of rolling after sowing or press wheels on the seed coulters. Most of the experiments were carried out without irrigation after sowing. The firming usually had a slightly positive effect on emergence when the water content in the surface layer at sowing was below the wilting point. When the water content in the surface layer was higher, firming often reduced emergence drastically, particularly with deep sowing and in coarse-textured soils. The main reason for negative effects was harmful hardening of the surface layer when the more firm seedbed gradually dried out. When irrigation kept the seedbed continuously moist, the negative effect of firming was almost eliminated. Very high initial water content in the basal layer tended to delay surface layer drying and hardening, and to reduce the negative effect of firming. Firming only slightly influenced the evaporative water losses from the soil. In contrast to the results presented here, previous field trials with cereals have usually resulted in more positive effects of rolling after sowing. This indicates that other effects than firming, such as modification of sowing depth and reshaping of the soil surface, are other important effects of rolling.