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1.
Until the 1970’s, Trichinella spiralis (Owen 1835) was considered the only species within the genus Trichinella. Then T. pseudospiralis (Garkavi 1972) was classified as a separate species on the basis of morphological and biological features. The remaining morphologically homogenous “T. spiralis-group” has been split into 4 different species (or subspecies) on the basis of their biological and biochemical characteristics; T. nativa (Britov & Boev 1972), T. nelsoni (Britov & Boev 1972), T. spiralis sensu stricto and T. britovi (Pozio et al. 1992). 相似文献
2.
The occurrence of Sarcocystis infection and pathological changes were recorded in samples of the heart, diaphragm, and oesophagus from 198 healthy sheep representing 3 different age groups, obtained from an abattoir.The infection rate of S. gigantea (syn. S. tenella) was 18.2 %, and the distribution within groups was: ewes 30.0 %, yearlings 11.6 %, lambs nil. The infection rate of S. tenella (syn. S. ovicanis) was 65.1 %, and the corresponding distribution was: ewes 83.5 %, yearlings 74.4 %, and lambs 25.0 %. A third type of Sarcocystis sp. displaying thick wall was found in 3 samples.Focal interstitial infiltrates of mononuclear cells were demonstrated in 47.9 % of the hearts, in 19.6 % of the diaphragms and in 31.3 % of the oesophagi. The occurrence of Sarcocystis and the focal interstitial mononuclear cell infiltrates were positively correlated (P < 0.0001). Morphologically identical sporocysts typical of S. tenella were produced by dogs and foxes fed naturally infected sheep tissues. A cat fed S. gigantea macrocysts produced sporocysts characteristic for the species.Sarcocystis; pathology; life cycle; final hosts; sheep. 相似文献
3.
Anette Moldestad Ellen Mosleth Fergestad Bernt Hoel Arne Oddvar Skjelvåg Anne Kjersti Uhlen 《Journal of Cereal Science》2011
The objective was to investigate effects of natural variation in temperature during grain filling on wheat (Triticum aestivum L) gluten quality. Seventeen field trials with four different varieties were conducted during the years 2005–2008. Temperature records were obtained from automatic weather stations located near the field trial sites. The period from heading to yellow ripeness was divided into 20 sub-phases of equal thermal time units, and a last sub-phase comprising the seven days after yellow ripeness. Partial Least Squares Regression was used to relate the temperature records of the different sub-phases to gluten quality analysed by the Kieffer Extensibility test and the SDS sedimentation test. 相似文献
4.
Strains of paramyxovirus type 1 (PMV-1) have been isolated from diseased racing pigeons in Sweden. One of these isolates was selected for studies of the pathogenicity and contagiousness in chickens.The same isolate was previously found to have a high intravenous pathogenicity index (IVPI) in 6 weeks old chickens.In three experiments it was found that the PMV-1 isolate was very pathogenic for 1 week old chickens but not pathogenic for 120 day old pullets inoculated intranasally and ocularly.Symptoms in the young chickens were similar to those seen in the neurotropic form of Newcastle disease. The mortality was high and the incubation period 5–11 days.The disease easily spread to young chickens kept in contact with diseased birds.The microscopic examination revealed an interstitial nonpurulent pneumonia and a nonpurulent encephalitis in the young chickens. In the pullets the only finding was a mild encephalitis.PMV-1 was recovered from all young chickens but not from the pullets.Both the chickens and the inoculated pullets developed antibodies to PMV-1. 相似文献
5.
Oddvar H. Ottesen Vegard Marschhäuser Igor Babiak 《Journal of the World Aquaculture Society》2012,43(3):375-386
The effects of cryopreservation on the viability, morphology and capability of spermatozoa in Atlantic cod, Gadus morhua L., were studied. The sperm was cryopreserved in straws using Hanks' balanced salt solution, hens' egg yolks and glycerol in the vapor of liquid nitrogen. Straws of cryopreserved sperm were stored in liquid nitrogen and thawed in seawater (35 C) for 8 sec before use. The motility of cryopreserved sperm was low (range 8–19%) compared to motility before freezing (range 69–76%). The fertilization rate (range 94–95%) in control groups using fresh sperm was significantly higher (P < 0.05) than in test groups (range 48–72%). In cryopreserved sperm, a relatively high percentage (range 82–93%) of the spermatozoa had changes in morphology. Many spermatozoa had no mitochondria; when mitochondria were present, the observed number varied from one and five in cryopreserved spermatozoa, and from two and seven in noncryopreserved spermatozoa. In groups where cryopreserved sperm was used, the hatching rate was lower (range 18–38%) than in control groups (range 41–63%), indicating higher mortality during embryonic development. Paternal effects on progeny performance were noted in the proportion of abnormalities but no negative effects were identified in newly hatched larvae produced using cryopreserved sperm. 相似文献
6.
Decrease in the quality and quantity of Atlantic halibut, Hippoglossus hippoglossus L., semen towards the end of the reproductive season hampers production of good-quality embryos. Therefore, cryopreservation
of spermatozoa is a method showing potential to facilitate controlled reproduction in Atlantic halibut. The present study
aimed at establishing the appropriate cryopreservation procedure. We tested 20 extenders composed of four various diluents
and five cryoprotectants (DMSO, DMA, methanol, propylene glycol, and glycerol) to determine the best extender. Then, we examined
cryopreservation quality using various methods of loading and various volumes of cryopreserved samples. In most of the tested
variants, sperm diluted with an extender showed high motility after 24-h incubation despite the high osmotic pressure of the
extender. Modified turbot extender (MTE) was the best of the tested diluents, securing the highest post-thaw motility (P < 0.05), and DMSO, DMA, and methanol were the best cryoprotectants (P < 0.05). There was no significant effect of 15-min equilibration of semen in MTE-based extenders prior to freezing on post-thaw
motility (P > 0.05). MTE-based extender was chosen as the most suitable. Semen cryopreserved in straws, Eppendorfs or Ziploc bags in
volumes ranging from 0.25 to 20 ml showed similar high fertilization ability. Survival of larvae produced with the cryopreserved
sperm did not differ from controls produced with freshly collected sperm. Motility 3 h after thawing was high but depended
on the type of cryoprotectant and the volume of cryopreserved sperm (P < 0.05). The developed cryopreservation procedure has been applied at our Atlantic halibut breeding station for seed production. 相似文献
7.
8.
Anette Edvardsen Rune Halvorsen Ann Norderhaug Oddvar Pedersen Knut Rydgren 《Landscape Ecology》2010,25(7):1071-1083
Habitat specificity analysis provides a tool for partitioning landscape species diversity on landscape elements by separating
patches with many rare specialist species from patches with the same number of species, all of which are common generalists
and thus provide information of relevance to conservation goals at regional and national levels. Our analyses were based upon
species data from 2201 patch elements in SE Norwegian modern agricultural landscapes. The context used for measuring habitat
specificity strongly influences the results. In general the gamma diversity contribution and core habitat specificity calculated
from the patch data set were correlated. High values for both measures were observed for woodland, pastures and road verges
whereas midfield islets and boundary transitional types were ranked low, as opposed to findings in traditional, extensively
managed agricultural landscapes. This is due to our study area representing intensively used agricultural landscape elements
holding a more trivial species composition, in addition to ruderals being favoured by fertility and disturbance, a finding
also being supported by the semi-natural affiliation index. Results obtained by use of checklist data from the same study
area diverged from patch data. Caution is needed in interpretation of habitat specificity results obtained from checklist
data, because modern agricultural landscapes contain several land types which are seldom surveyed by botanists, thus being
under-represented in the data set. We propose the use of core habitat specificity and gamma diversity contribution in parallel
to obtain a value neutral diversity assessment that addresses patch uniqueness and other properties of conservation interests. 相似文献
9.
Cecilia Campos Vargas Stefano Peruzzi Anjana Palihawadana Oddvar Ottesen Ørjan Hagen 《Aquaculture Research》2017,48(1):259-269
This study has investigated the muscle growth of diploid and triploid Atlantic cod (Gadus morhua) juveniles raised in replicate tanks over a period of 29 weeks and analysed at three sampling points (February, June and September). Data for weight, length, condition factor (K), muscle fibre growth and myogenic progenitor cells (MPCs) number were collected and results were analysed in relation to body growth and ploidy status. Diploids were significantly heavier than triploids throughout the trial (~10–20%) and had K in June and September samplings. Over the whole period, the rate of muscle fibres' recruitment was 318 fibres per day and 252 fibres per day for diploid and triploid cod respectively. The larger body weight of diploids resulted in a total number of fast fibre number of 114 979 compared to 91 086 in triploids. The average diameter of the 2.5% of the smallest fibres (2.5th percentile) was higher in diploids than triploids at the start of the trial, with a reversed picture for the average of the upper 2.5% (97.5th percentile) at the end of the trial. The probability density function of the estimated muscle fibre diameters showed similar fibre size distribution between size‐matched diploids and triploids at all sample points. The peak fibre diameter was approximately 25 μm in February and increased to approximately 50 μm in June and September, irrespectively of ploidy. Pax 7 were used as molecular markers for MPCs. A positive correlation between Pax 7+ cells and total body length was observed only among triploid fish at the onset of the experiment. 相似文献
10.
Oddvar Haveraaen 《Scandinavian Journal of Forest Research》2014,29(7):669-674
The effect of ash fertilization on height growth and volume production of Scots pine (Pinus sylvestris L.) was studied on oligotroph peatland in southeast Norway. In the year 1944, plots 15 m × 15 m size were fertilized with 0, 4, 7, and 10 tons ha?1 of wood or peat ash. The area was treeless, but a satisfactory number of pine seedlings were present. All measurements were confined to the central inner plot, 10 m × 10 m area. Most plots were re-fertilized with 10 tons of wood ash ha?1 in the year 1993. Wood ash had higher content of nutrients, and generally, it had greater growth enhancement effect than peat ash. When the amount of ash was increased, volume production significantly increased for the age period 38–50 years and the total production at age 50 years. The mean annual increment during the first 50 years was about 6 m3 ha?1 for the plots applied with 10 tons of ash ha?1. Trees on plots fertilized with 7 or 10 tons in 1944 and replenished with 10 tons ha?1 at age 50 years (1993) had a mean annual increment of 14 m3 ha?1 for the stand age period 51–68 years. Over time some tree roots from control plots and plots fertilized with 4 tons ha?1 have captured nutrients from richer plots. Such effect is to a smaller extent relevant for treatment 7 tons. It is concluded that the content of mineral nutrients of wood and peat ash makes these ashes well suited as fertilizers on peatland. 相似文献