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排序方式: 共有486条查询结果,搜索用时 15 毫秒
101.
Trine Ytrestøyl Harald Takle Jelena Kolarevic Sara Calabrese Gerrit Timmerhaus Bjørn O. Rosseland Hans C. Teien Tom O. Nilsen Sigurd O. Handeland Sigurd O. Stefansson Lars O. E. Ebbesson Bendik F. Terjesen 《Journal of the World Aquaculture Society》2020,51(2):373-392
Producing a larger post-smolt in recirculating aquaculture systems (RAS) could shorten the production time in sea cages and potentially reduce mortality. Knowledge of the biological requirements of post-smolts in closed-containment systems is however lacking. In the present study, the effects of salinity and water velocity on growth, survival, health, and welfare of Atlantic salmon reared in RAS were examined. Salmon smolts were stocked in three separate RAS with salinities of 12, 22, and 32‰ and subjected to high (1.0 body lengths per s−1) or low (0.3 body lengths second−1) water velocity. Growth performance, survival, welfare, and physiological stress responses were monitored until the fish reached a bodyweight of around 450 g. Growth rate was higher at lower salinity and higher water velocity generally had a positive effect on growth in all salinities. Feed conversion ratio was lower at 12‰ compared to the 22 and 32‰ when the fish were between 250 and 450 g. Higher mortality, elevated plasma cortisol levels, higher incidence of cataract, and a higher expression of stress-induced genes in the skin (iNOS, Muc5ac-like) indicated a negative effect of higher salinity on fish welfare. Male maturation was low (<1%), and not affected by salinity or water velocity. 相似文献
102.
Björn Baßmann Harvey Harbach Stephan Weißbach Harry W. Palm 《Journal of the World Aquaculture Society》2020,51(1):183-199
We investigated the effects of plant density on the welfare of African catfish, Clarias gariepinus, in coupled aquaponics over 85 days. The moderate density (mpd) of basil, Ocimum basilicum, was compared with the high density (hpd) and control (n = 0). The behavior was analyzed by visual and video observations, and after the application of induced stressors, skin injuries, blood glucose, lactate, and plasma cortisol responses were considered. The hpd fish showed the least activity (control: visual 77.8%, video 81.6%; mpd: 74.6%, 82.6%; hpd: 63.2% [p < 0.05], 78.8%). High agonistic behavior (control: 5, 131; mpd: 4, 57; hpd: 1, 45) and the highest number of injuries (control: 3.9; mpd: 2.9; hpd: 3.4) were observed in the control. Glucose and lactate levels did not differ significantly (control: 5.5, 2.6 mmol/L; mpd: 5.6, 2.7 mmol/L; hpd: 5.3, 2.6 mmol/L); however, cortisol levels did (control: 18.8 ng/mL, mpd: 19.9 ng/mL, hpd: 25.8 ng/mL). pH adjustment led to additional stress, resulting in temporal cortisol alterations. While in the control and mpd, low cortisol levels were followed by acute responses and downregulation, the hpd fish showed prior elevation and lagged an acute response. However, comparing injuries and behavioral patterns with control, aquaponics with high basil density influenced African catfish positively. 相似文献
103.
M. Marinova-Todorova N. Björklund J. Boberg D. Flø J. Tuomola M. Wendell S. Hannunen 《EPPO Bulletin》2020,50(2):249-267
Plant pests moved along with the trade in ornamental plants could pose a threat to forests. In this study plant pests potentially associated with this pathway were screened to identify pests that could pose a high risk to the coniferous forests of Finland, Sweden and Norway. Specifically, the aim was to find pests that potentially could fulfil the criteria to become regulated as quarantine pests. EPPO’s commodity study approach, which includes several screening steps, was used to identify the pests that are most likely to become significant pests of Picea abies or Pinus sylvestris. From an initial list of 1062 pests, 65 pests were identified and ranked using the FinnPRIO model, resulting in a top list of 14 pests, namely Chionaspis pinifoliae, Coleosporium asterum s.l., Cytospora kunzei, Dactylonectria macrodidyma, Gnathotrichus retusus, Heterobasidion irregulare, Lambdina fiscellaria, Orgyia leucostigma, Orthotomicus erosus, Pseudocoremia suavis, Tetropium gracilicorne, Toumeyella parvicornis, Truncatella hartigii and Xylosandrus germanus. The rankings of the pests, together with the collected information, can be used to prioritize pests and pathways for further assessment. 相似文献
104.
105.
106.
Rodomiro Ortiz Minna Nurminiemi Sten Madsen Odd Arne Rognli Åsmund Bjørnstad 《Euphytica》2002,126(2):283-289
Accurate assessments of genetic gains ensuing from plant breeding for the most important agronomic characteristics in Nordic
spring barley (Hordeum vulgareL.) are not available. Hence this research was aimed to determine the rate of genetic improvement in the Nordic barley breeding
pool. This study included 90, 2-row spring barley cultivars released (1942–1988) and29, 6-row spring barley cultivars released(1930–1991)
adopted by Nordic farmers that were tested in four Nordic locations for three consecutive years. Relative genetic gain owing
to plant breeding was 13% in2-row barley and 34% in 6-row barley for grain yield. The absolute gain for this characteristic
was 13 ± 3 kg ha-1 year -1 in 2-row barley, and22 ± 3 kg ha-1 year-1 in6-row barley. Improved yield was achieved in Nordic barley by reducing plant height(0.20 ± 0.04 cm year-1 for 2-rowbarley and 0.16 ± 0.06 cm year-1for 6-row cultivars), thereby reducing significantly lodging (0.5 ± 0.1%year-1 and 0.4 ± 0.1year-1), and increasing significantly the harvest index (0.0008 ± 0.0002year-1 and 0.0018 ± 0.0002year-1). Additionally, in 2-row spring barley cultivars resistance to powdery mildew (0.19 ± 0.08% year-1)and thousand-kernel weight (0.07 ±0.03 g year-1) were also significantly enhanced, whereas hectoliter weight was improved (0.06 ± 0.02 kg year-1)in 6-row barley cultivars in the period investigated.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
107.
L. Reitan S. Grønnerød T.P. Ristad S. Salamati H. Skinnes R. Waugh Å. Bjørnstad 《Euphytica》2002,123(1):31-39
Rhynchosporium secalis is a serious pathogen of barley (Hordeum vulgare L.) in central Norway. A breeding effort was initiated in 1977 to introduce resistance from different sources into adapted genotypes, and the first cultivar from the program was recently released. However, little is known about the resistance genes introgressed in this cultivar or in advanced breeding lines. An effort was made to address this issue through a set of isolates and available molecular markers. Fourteen breeding lines and their resistance donors were investigated by evaluating their reactions to 11 R. secalis isolates. Bulked segregant analysis was used to identify molecular markers linked to resistance genes in 12 of the breeding lines. The isolates were found to be of less discriminating value than the markers. Useful information has been obtained as to the nature of several of the resistance genes introgressed. Eight of the 12 breeding lines contained introgressed genes that were located at the `complex Rh' locus on chromosome 3H and hence may not easily be pyramided into the same genotype. Previous information about the nature of the resistance in `Jet' is questioned. Neither of the resistance genes Rh or Rh2 seems to have been incorporated into Norwegian breeding material. 相似文献
108.
Minna Nurminiemi Sten Madsen Odd Arne Rognli Âsmund Bjørnstad Rodomiro Ortiz 《Euphytica》2002,127(1):123-132
Variation in agronomic and quality characteristics was investigated in 220 Nordic spring barley cultivars across distinct
environments (6 locations during 3 years) in the Nordic Region of Europe. The objectives of this research were to determine
the importance of the genotype by environment interaction in all characteristics evaluated and to establish the relationship
among different stability statistics for grain yield. Combined analysis of variance across locations indicated that both environments
and genotype by environment interactions influenced significantly the cultivar phenotypes for all characteristics, irrespective
of their type (row number) or earliness. The first two interaction principal component axes of the additive-main-effects-and-multiplicative-interaction
(AMMI) model accounted together between 35% and 75% of the total genotype-by-environment interaction for all characteristics.
Grain yield was, on average, higher in 2-row than in 6-row cultivars, which were significantly earlier in heading and grain
maturity than the former. However, in some of the most northern locations, 6-row barley cultivars significantly outyielded
on average 2-row barley lines. The genotype by location interaction variance (σ2
GL) accounted by each genotype was significantly associated to the deviation from regression (Tai's λ) while the coefficient
of regression (β) was significantly correlated to the IPCA1 and IPCA2 of the AMMI model in 2-row, 6-row and early barley cultivars.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
109.
Anneli Tallberg Bjørn O. Eggum 《Plant foods for human nutrition (Dordrecht, Netherlands)》1981,31(2):151-161
The protein quality of some improved high-lysine barley genotypes was measured chemically — including amino acid analyses and sequential protein extraction — and biologically in N-balance experiments with growing rats. The increased content of lysine, mainly due to an enhancement of the glutelin protein fraction, and other essential amino acids improved the nutritional quality as the biological value of the protein was significantly higher in the high-lysine material compared to normal. This improvement is undoubtedly of importance to meet the essential amino acid requirement of man as well as monogastric animals. 相似文献
110.
Arteriosclerosis in the ventral aorta and epicarditis in the bulbus arteriosus of Atlantic salmon (Salmo salar L) 下载免费PDF全文
A S Dalum K H Kristthorsdottir D J Griffiths K Bjørklund T T Poppe 《Journal of fish diseases》2017,40(6):797-809
Spontaneous mortality of seemingly healthy, farmed Atlantic salmon (Salmo salar L) is an increasing problem in Norwegian aquaculture. In this study, we present a morphological study of the previously undescribed syndrome of arteriosclerosis of the ventral aorta and epicarditis of the adjacent bulbus arteriosus found in farmed Atlantic salmon, with wild‐captured fish as a control group. Both the ventral aorta and epicardium are vital for correct arterial compliance and vascular resistance in the respiratory capillaries of the gills. We discuss the possible implications of ventral aorta arteriosclerosis and epicarditis for blood vascular health and in particular for the increasing frequency of spontaneous gill bleeding in farmed salmon. As both these conditions primarily occur in farmed salmon, we suggest that they should be considered pathological. 相似文献