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61.
Rune Rødbotten Kjell Ivar Hildrum Jan Berg 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(2):72-80
In total, 56 bulls of Angus 2 NRF or Limousin 2 NRF were fed two levels (either 2.5 or 5.0 kg animal -1 day -1 ) of concentrate from 12 weeks of age to slaughter in a 2 2 2 factorial design with cross-breed and concentrate level as fixed factors. The concentrate was a mixture with barley, oats, wheat, soyabean and molasses as main components. In addition, the animals had ad libitum access to grass silage. As expected, the bulls fed the high concentrate diet had higher growth rate than bulls fed moderate level of concentrate. Angus 2 NRF bulls fed the high level of concentrate showed the highest growth rate of the four subgroups and were on average slaughtered at the age of 15 months. Limousin 2 NRF bulls fed the moderate level of concentrate were the subgroup with the lowest growth rate and needed 20 months to reach the target slaughter weight, which on average was 280 and 340 kg for Angus 2 NRF and Limousin 2 NRF, respectively. Although the animals at the high concentrate level had a greater intake of energy day -1 , there was no significant difference in feed conversion calculated as FUm kg -1 gain between the subgroups. The Limousin cross-breeds had significantly higher relative proportions of muscle in the carcass, but less bone and fat than the Angus cross-breeds. Consequently, the Limousin 2 NRF bulls achieved better muscularity grading in the EUROP system than the Angus 2 NRF bulls. Concentrate level yielded different fatness scores in the EUROP system, while breed did not. The correlation between carcass weight and psoas major or longissimus dorsi muscles was stronger for the former muscle. There was a tendency for Angus 2 NRF bulls fed the moderate concentrate level to have more tender longissimus muscle than the other subgroups, but this difference was not significant. 相似文献
62.
Atlantic salmon were fed 40, 300 or 1100 mgall-rac-α-tocopheryl acetate kg feed?1 for 12 weeks.After 6 weeks half of the fish in each group were marked and vaccinated (i.p.injection) against furunculosis and vibriosis. Liver α-tocopherol levelsreflected the dietary input after 6 and 12 weeks of feeding. Noimmunomodulatoryeffects of dietary vitamin E on baseline levels of the immune parameters beforevaccination were detected in this study, as evaluated by antibody dependent andspontaneous plasma complement activities. In general, vaccination increasedplasma complement activities and the number of antigen specific antibodyproducing cells as compared with unvaccinated control fish, but with nodifferences with respect to the vitamin E regimes. Also the ability ofunvaccinated fish to withstand experimental furunculosis was unaffected bydietary vitamin E. The concentrations of α-tocopherol and ascorbic acidinthe liver were, however, negatively affected 6 weeks post vaccination comparedto respective unvaccinated fish. 相似文献
63.
Rune H. Økland Harald Bratli Wenche E. Dramstad Anette Edvardsen Gunnar Engan Wendy Fjellstad Einar Heegaard Oddvar Pedersen Heidi Solstad 《Landscape Ecology》2006,21(7):969-987
Knowledge of variation in vascular plant species richness and species composition in modern agricultural landscapes is important
for appropriate biodiversity management. From species lists for 2201 land-type patches in 16 1-km2 plots five data sets differing in sampling-unit size from patch to plot were prepared. Variation in each data set was partitioned
into seven sources: patch geometry, patch type, geographic location, plot affiliation, habitat diversity, ecological factors,
and land-use intensity. Patch species richness was highly predictable (75% of variance explained) by patch area, within-patch
heterogeneity and patch type. Plot species richness was, however, not predictable by any explanatory variable, most likely
because all studied landscapes contained all main patch types – ploughed land, woodland, grassland and other open land – and
hence had a large core of common species. Patch species composition was explained by variation along major environmental complex
gradients but appeared nested to lower degrees in modern than in traditional agricultural landscapes because species-poor
parts of the landscape do not contain well-defined subsets of the species pool of species-rich parts. Variation in species
composition was scale dependent because the relative importance of specific complex gradients changed with increasing sampling-unit
size, and because the amount of randomness in data sets decreased with increasing sampling-unit size. Our results indicate
that broad landscape structural changes will have consequences for landscape-scale species richness that are hard or impossible
to predict by simple surrogate variables. 相似文献
64.
Antti P. Eloranta Anna Siwertsson Rune Knudsen Per‐Arne Amundsen 《Ecology of Freshwater Fish》2011,20(4):558-568
Abstract – Habitat use and diet of Arctic charr (Salvelinus alpinus) coexisting with European whitefish (Coregonus lavaretus) and grayling (Thymallus thymallus) were studied in one deep and two relatively shallow subarctic lakes in northern Norway. Stomach content and stable isotope analyses revealed clear and temporally stable resource partitioning between the species in all three lakes. Arctic charr had a wide and flexible trophic niche and was the only piscivorous species. In contrast, whitefish and grayling had remarkably stable planktivorous and benthivorous niches, respectively. In the deepest lake, Arctic charr together with grayling mainly utilised littoral benthos, while piscivory was more prevalent in Arctic charr in the two shallower lakes. In one of the shallow lakes, whitefish was apparently relegated to the inferior profundal niche because of dominance of the littoral by grayling. Our results suggest that Arctic charr may not necessarily need an extensive profundal zone as a refuge, but can coexist with whitefish if a third competing fish species like grayling occurs in the littoral habitat or if profitable small prey fish are available. The study demonstrates that strong dietary plasticity of Arctic charr is instrumental in the observed coexistence with the commonly competitively superior whitefish. 相似文献
65.
Okadaic acid (OA) and microcystin (MC) as well as several other microbial toxins like nodularin and calyculinA are known as tumor promoters as well as inducers of apoptotic cell death. Their intracellular targets are the major serine/threonine protein phosphatases. This review summarizes mechanisms believed to be responsible for the death induction and tumor promotion with focus on the interdependent production of reactive oxygen species (ROS) and activation of Ca2+/calmodulin kinase II (CaM-KII). New data are presented using inhibitors of specific ROS producing enzymes to curb nodularin/MC-induced liver cell (hepatocyte) death. They indicate that enzymes of the arachidonic acid pathway, notably phospholipase A2, 5-lipoxygenase, and cyclooxygenases, may be required for nodularin/MC-induced (and presumably OA-induced) cell death, suggesting new ways to overcome at least some aspects of OA and MC toxicity. 相似文献
66.
Sten Ivar Siikavuopio Rune Knudsen Per Arne Amundsen Bjørn Steinar Sæther Philip James 《Aquaculture Research》2012,44(1):8-12
The effect of three different temperatures on growth in a first progeny generation, hatchery reared, subarctic population of European whitefish (Coregonus lavaretus L.) were investigated. The whitefish (start weight 444 g, ±SD 125 g) were reared for 60 days at three constant temperatures; 15, 18 and 21°C and under ambient light regimes for 70°N latitude. The results showed that temperature had a significant influence on the growth of the fish with the highest increase in weight increment occurring at 18°C (mean final weight 656 g ± SD 151 g) compared with the growth of fish held at 15°C (mean final weight 591 g ± SD 143 g) and 21°C (mean final weight 505 g ± SD 121 g). The cumulative per cent mortality of the fish during the experimental period increased with increasing temperature, from 10% at 15°C to 30% at 21°C. The present study indicates that the optimal temperature for farming of European whitefish is somewhere between 15 and 18°C rather than between 18 and 21°C. 相似文献
67.