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Harald Volden Weiert Velle Øystein V. Sjaastad Arnfinn Aulie Odd Magne Harstad 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(1):35-45
The main purpose of this study was to examine sources of variation in free amino acids (FAA) in the rumen and their relative contribution to the total duodenal amino acid supply. Six cannulated lactating dairy cows fed three concentrate mixtures differing in ruminally degradable intake protein (101, 114 and 134 g kg-1 dry matter) at two levels of intake (19.3 vs 9.8 kg dry matter day-1 相似文献
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Odd J. Jacobsen 《Aquaculture (Amsterdam, Netherlands)》1977,11(1):81-84
The growth of brown trout (Salmo trutta) yearlings (18 months) was studied at environmental pH levels of about 6.26, 5.44 and 5.00 and a daily ration of 2.9% of the initial body weight. Growth increments for fish at each pH level during a 48-day period were similar. 相似文献
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Frøydis T. Gillund Lise Nordgaard Thomas Bøhn Odd Gunnar Wikmark Heidi Sjursen Konestabo Angelika Hilbeck 《Potato Research》2013,56(4):293-324
The deliberate release of any genetically modified (GM) organism in the European Union requires an environmental risk assessment (ERA) prior to commercialisation, including impact assessment on nontarget organisms. We report from two expert workshops where a newly developed selection procedure for identification of ecologically relevant testing organisms was applied to the case of a GM potato with increased resistance to late blight, planned for cultivation in southern Scandinavia. Species known to contribute to important ecological functions in the receiving environment were selected in a stepwise procedure, to arrive at a practical number of ecologically relevant species that are likely to be exposed to the transgene and suitable for experimental testing. Four ecological functional categories were identified: herbivory and disease transmission, natural enemies, ecological soil processes and pollination. Among these, relevant nontarget species were identified for herbivores and soil living pathogens, natural enemies and decomposers/beneficial soil organisms. Out of a total of 16 herbivores, 17 soil-living pathogens, 49 natural enemies and 14 decomposers/beneficial soil organisms in the initial lists, 8 herbivores, 10 soil-living pathogens, 15 natural enemies and 11 decomposers/beneficial soil organisms were identified as possible testing organisms, based on ecological criteria. These findings are highly relevant for determining the scope and structure of an ERA of this type of GM potato. The selection procedure could not be completed because of insufficient information about tissue- and developmental stage-specific expression levels of the transgenic products for this particular GM potato. Thus, the case study illustrates some of the difficulties and knowledge gaps that limit the relevance and quality of ERA of GM plants. 相似文献
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Odd Inge Forsberg 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3):183-200
Research on management practices in fish farming has traditionally focused on two topics: production planning and forecasting of prices. This article combines these two areas of research, and illustrates how information on price patterns can change production plans, and hence increase the value of the farm enterprise. It will present a model farm and illustrate, with different levels of price information, how information on future prices alters the original production plan and hence creates extra value for the farmer. Although the specifics and empirical application of the paper are on salmon and salmon farming, the ideas and general results could be applied to all farmed species. 相似文献
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Vendace and whitefish in Lake Osensjøen (boreal south‐east Norway) were studied by means of gillnet test fishing (1976–2013) and hydro acoustic acquisition (1986–2011). Vendace increased in number between 1998 and 2009 while growth and size at maturity decreased. The relative density of whitefish decreased in the pelagic habitat, whereas growth and size remained the same. Both species exhibited varying year‐class strength. Whereas strong year‐classes of both species became less frequent after 1980 than before this, this seemed to change after 2000, especially for vendace. Generalised additive models suggested a strong positive relationship between July/August mean air temperature and year‐class strength of both vendace and whitefish. Whitefish recruitment was also negatively affected by the new regulation regime implemented since 1981, and positively correlated with water level after hatching and by late ice off. The reason for the diverging impacts of environmental factors on the two species may be that vendace spawn in deeper waters that whitefish do. The results indicate that increasing summer temperatures benefit recruitment of both species, whereas low water level and early ice off will harm whitefish recruitment. Both trends are caused by climate warming. It may be speculated that increased density of the specialised plankton feeding vendace may affect the algal community through increased predation on herbivorous zooplankton and potentially affect the trophic state of the lake. 相似文献
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Odd Inge Forsberg 《Aquaculture Economics & Management (Blackwell Science)》2013,17(2):143-158
Abstract The main harvest planning problem in commercial fish farms is to determine the best time‐sequence of harvesting different fish cohorts in order to maximize the overall farm profit. Due to both annual and fish‐size variations in market prices, future forecasts of fish growth and size distribution are required to optimize harvest plans. Two management strategies for harvesting size‐structured fish cohorts are considered. The first strategy allows the fish farmer, at any time, to size‐grade, harvest and sell the most profitable fish sizes from the standing stock. The second strategy allows the fish farmer to harvest and sell a fish batch with similar size distribution as that of the standing stock. In this paper, two size‐structured fish growth models have been built to fit the two management strategies. The growth models are integrated in a multiperiod linear programming model that optimizes the harvest outputs for each of the two management strategies. Model outputs demonstrate clearly that it is more profitable to size‐grade fish prior to harvest compared to harvesting a batch of fish with similar size distribution to that of the standing stock. Five different harvest operations constraints have been identified for commercial salmon farming. The decrease in profitability of fish farming is shown for a variety of harvest operation constraints. 相似文献
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Abdelhameed Elameen Siri Fjellheim Arild Larsen Odd Arne Rognli Leif Sundheim Susan Msolla Esther Masumba Kiddo Mtunda Sonja S. Klemsdal 《Genetic Resources and Crop Evolution》2008,55(3):397-408
Sweet potato (Ipomoea batatas L.) is the fifth most important crop in the developing countries after rice, wheat, maize and cassava. The amplified fragment
length polymorphism (AFLP) method was used to study the genetic diversity and relationships of sweet potato accessions in
the germplasm collection of Sokoine University of Agriculture, Morogoro and Sugarcane Research Institute, Kibaha, Tanzania.
AFLP analysis of 97 sweet potato accessions using ten primer combinations gave a total of 202 clear polymorphic bands. Each
one of the 97 sweet potato accessions could be distinguished based on these primer combinations. Estimates of genetic similarities
were obtained by the Dice coefficient, and a final dendrogram was constructed with the un-weight pair-group method using arithmetic
average. AFLP-based genetic similarity varied from 0.388 to 0.941, with a mean of 0.709. Cluster analysis using genetic similarity
divided the accessions into two main groups suggesting that there are genetic relationships among the accessions. Principal
Coordinate analysis confirmed the pattern of the cluster analysis. Analysis of molecular variance revealed greater variation
within regions (96.19%) than among regions (3.81%). The results from the AFLP analysis revealed a relatively low genetic diversity
among the germplasm accessions and the genetic distances between regions were low. A maximally diverse subset of 13 accessions
capturing 97% of the molecular markers diversity was identified. We were able to detect duplicates accessions in the germplasm
collection using the highly polymorphic markers obtained by AFLP, which were found to be an efficient tool to characterize
the genetic diversity and relationships of sweet potato accessions in the germplasm collection in Tanzania. 相似文献