Correlated response to selection for litter size in pigs: II. Carcass,meat, and fat quality traits     

Estany J  Villalba D  Tor M  Cubiló D  Noguera JL 《Journal of animal science》2002,80(10):2566-2573

Data on a pig line selected for litter size (H) and a control line (C) were used to estimate the correlated responses to litter size in carcass, meat, and fat quality traits. The differences between the genetic means of animals from line H and line C were used to estimate correlated responses. No differences were found between the two lines in carcass measurements except backfat depth, which was higher (P < 0.05) in line H (0.69 +/- 0.28 mm). This led to a decrease (P < 0.05) in predicted carcass lean content (-6.0 +/- 2.7 g/kg). Differences in joint weight distribution between lines were primarily due to belly weight, which was higher (P < 0.05) in line H (6.3 +/- 1.2 g/kg). There were no important changes in meat quality traits. Chemical composition of semimembranosus muscle (SM) and subcutaneous backfat (SB) differed between lines only for DM in SB, which was higher (P < 0.05) in line H (15.1 +/- 7.1 mg/g), and for the fatty acid composition of intramuscular fat. The fatty acid profile in line H showed a lower (P < 0.01) proportion of polyunsaturated fatty acids (-14.7 +/- 4.8 mg/g FA), particularly with regard to the content of linoleic acid (-12.5 +/- 3.9 mg/g FA). It is concluded that selection for litter size reduced the lean content in the carcass but the proportion of high-priced cuts and meat quality traits were not affected. However, selection may lead to changes in the composition of intramuscular fat lipids towards a lower content of polyunsaturated fatty acids. The observed correlated effects can be interpreted assuming that selected pigs are more mature at the same weight, though the underlying genetic and physiologic processes that cause them are unknown. The results of this experiment indicate that the metabolic pathways taking part in fat metabolism should be considered first.  相似文献   

Analysis and management of resistance to chemotherapeutants in salmon lice,Lepeophtheirus salmonis (Copepoda: Caligidae)     

Denholm I  Devine GJ  Horsberg TE  Sevatdal S  Fallang A  Nolan DV  Powell R 《Pest management science》2002,58(6):528-536

In Northern Europe and Canada, the salmon louse, Lepeophtheirus salmonis (Kr?yer), seriously affects the marine phase of salmon production. Although the problem is long-standing, the development of sustainable methods of pest management has been unable to keep pace with the intensification of production, leading to large-scale reliance on very few chemotherapeutants. This runs the risk of selecting for genetically determined resistance in target organisms. There are many examples of similar evolutionary adaptations in arthropod pests of arable crops, livestock and human health. Several hundred pest species are now documented as being resistant to one or more chemical classes of insecticides and acaricides. Many of these compounds are identical or closely related to ones currently employed against salmon lice. It is, therefore, opportune to consider what lessons have been learnt from contending with resistance in terrestrial organisms, the implications for sustainable use of chemotherapeutants in aquaculture, and the potential for developing effective resistance management strategies. An EU-funded project named SEARCH (QLK2-CT-2000-00809) has been initiated to explore in more detail the diagnosis, incidence, dynamics and management of resistance to chemotherapeutants in L salmonis.  相似文献   

Organophosphate poisoning of Atlantic salmon in connection with treatment against salmon lice     

Tor Einar Horsberg  Tonje Hy  Inger Nafstad 《Acta veterinaria Scandinavica》1989,30(4):385-390

Three incidents with high mortality in Atlantic salmon after trichlorfon treatment against salmon lice are described. All 3 incidents occurred at water temperatures of 12 degrees C or higher. The mean brain acetylcholinesterase (AChE) activity of dead fish was less than 20% of normal activity, while survivors showed mean activities of 22-61% of normal levels. Dichlorvos residues in muscular and liver tissues ranged from nondetectable levels to 0.2 micrograms/g tissue. The strongest inhibition of brain AChE was found in association with the highest dichlorvos residues. Substantial AChE-inhibition was, however, also found in samples in which dichlorvos residues could not be detected. AChE-determination was found to be more reliable than residue analysis for the diagnosis of organophosphate poisoning in salmon.  相似文献   

The use of morphometric characters to discriminate specimens of laboratory-reared and wild populations of Gyrodactylus salaris and G. thymalli (Monogenea)     

Shinn AP  Hansen H  Olstad K  Bachmann L  Bakke TA 《Folia parasitologica》2004,51(2-3):239-252

Gyrodactylus thymalli Zitnan, 1960 and G. salaris Malmberg, 1957 have an indistinguishable ribosomal internal transcribed spacer (ITS) DNA sequence, but exhibit surprisingly high levels of intra- and interspecific sequence variation of the mitochondrial cytochrome oxidase I (CO1) gene. To test whether different populations of these reportedly very similar species could be discriminated using morphometric methods, we examined the morphometry of four different populations representing different mitochondrial clades. Twenty five point-to-point measurements, including five new characters of the attachment hooks, were recorded from three Norwegian laboratory populations (G. salaris from the Rivers Lierelva and Rauma, and G. thymalli from the River Rena), and from one wild population of G. thymalli from the River Test, UK. The Norwegian populations were kept under identical environmental conditions to control for the influence of temperature on the haptoral attachment hooks. Data were subsequently subjected to univariate and linear stepwise discriminant analyses. The model generated by the linear stepwise discriminant analysis used 18 of the 25 original variables, the first two roots accounting for 96.6% of the total variation between specimens. The hamulus shaft length accounts for 66.7% of the overall correct classification efficiency. Based on morphometry, all specimens were assigned to the correct species. Apart from three specimens of G. salaris from the River Lierelva population which were misclassified as belonging to the G. salaris Rauma population, all specimens were assigned to the correct population. Thus, populations of Gyrodactylus identified by mtDNA can also be discriminated using morphometric landmark distances.  相似文献   

Inductive and noninductive conditions on in vitro tuberisation and microtuber dormancy in potato (Solanum tuberosum subspeciestuberosum and subspeciesandigena)     

V. Vecchio  S. Benedettelli  Luisa Andrenelli  E. Palchetti  L. Espen 《Potato Research》2000,43(2):115-123

Summary The effect of growth conditions (medium and photoperiod) on in vitro tuberisation and microtuber dormancy of the cv. Désirée (Solanum tuberosum subspeciestuberosum) and Imilla Negra (Solanum tuberosum subspeciesandigena) was evaluated. The short photoperiod and presence of CCC in the medium reduced the dry matter of plants as well as the size of microtubers. The two cultivars showed a difference, in favour of Désirée, in the percentage of plants having more than one tuber and in the average time of sprouting after storage. The average time of sprouting was more rapidly obtained under long days and in a medium without CCC. The CCC and short days caused the same dormancy conditions and the same K⁺ quantity in the microtubers. The microtubers mineral composition is involved in the dormancy status.  相似文献   

Anchorage of mature conifers: resistive turning moment, root-soil plate geometry and root growth orientation     

Lundström T  Jonas T  Stöckli V  Ammann W 《Tree physiology》2007,27(9):1217-1227

Eighty-four mature Norway spruce (Picea abies L. Karst), silver fir (Abies alba Mill) and Scots pine (Pinus sylvestris L.) trees were winched over to determine the maximum resistive turning moment (M(a)) of the root-soil system, the root-soil plate geometry, the azimuthal orientation of root growth, and the occurrence of root rot. The calculation of M(a), based on digital image tracking of stem deflection, accounted not only for the force application and its changing geometry, but also for the weight of the overhanging tree, representing up to 42% of M(a). Root rot reduced M(a) significantly and was detected in 25% of the Norway spruce and 5% of the silver fir trees. Excluding trees with root rot, differences in M(a) between species were small and insignificant. About 75% of the variance in M(a) could be explained by one of the four variables--tree mass, stem mass, stem diameter at breast height squared times tree height, and stem diameter at breast height squared. Among the seven allometric variables assessed above ground, stem diameter at breast height best described the root-soil plate dimensions, but the correlations were weak and the differences between species were insignificant. The shape of the root-soil plate was well described by a depth-dependent taper model with an elliptical cross section. Roots displayed a preferred azimuthal orientation of growth in the axis of prevailing winds, and the direction of frequent weak winds matched the orientation of growth better than that of rare strong winds. The lack of difference in anchorage parameters among species probably reflects the similar belowground growth conditions of the mature trees.  相似文献   

Upper susceptibility threshold limits with confidence intervals: a method to identify normal and abnormal population values for laboratory toxicological parameters, based on acetylcholinesterase activities in sea lice     

Fallang A  Larsen S  Horsberg TE 《Pest management science》2006,62(3):208-213

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Assessment of suitable substrates for lumpfish in sea pens     

Albert K. Imsland  Patrick Reynolds  Gerhard Eliassen  Thor A. Hangstad  Ane V. Nytrø  Atle Foss  Erik Vikingstad  Tor Anders Elvegård 《Aquaculture International》2015,23(2):639-645

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The role of exotic tree species in Nordic forestry     

Erik Dahl Kjær  Albin Lobo  Tor Myking 《Scandinavian Journal of Forest Research》2014,29(4):323-332

The selection of suitable tree species is a prerequisite for successful forestry, and the use of exotic species as an alternative to native species is often a relevant option. In this paper, we discuss this option in relation to the present and future wood production in Nordic forestry. We revisit the vegetation and forest history and its implications for the interest in using exotic species. We review to what extent exotic species can contribute to increased economic returns from forest plantings and the potential negative ecological effects associated with introduction of new species. Considering the expected climate changes, we discuss whether and how the increased use of exotic species can contribute to sustained and increased health and productivity of Nordic forests without jeopardising ecological and social values.  相似文献   

Extreme acidification of a lake in southern Norway caused by weathering of sulphide-containing bedrock     

Atle Hindar  Espen Lydersen 《Water, air, and soil pollution》1994,77(1-2):17-25

In 1986 Lake Langedalstjenn in southern Norway was a weakly acidified lake with a pH of 5.2–5.6, and an average concentration of SO₄ of 330 μeq L^?1. The total Al concentration varied between 10 and 20 μeq L^?1 (expressed as Al³⁺). The lake supported populations of brown trout and perch and had supplied about 100 people with drinking water until the late 1980's. During 1986–1989, a dramatic change in the water chemistry occurred because of blasting of and weathering of sulphidic gneisses in the watershed. The oxidation of sulphide to sulphate (sulphuric acid) caused an increase in the SO₄ concentration of the draining stream of up to ≈ 4800 μeq L^?1. Weathering and/or cation exchange of Ca and Mg neutralized approximately 52% of the protons from the sulphuric acid production, while about 46% were consumed by mobilization of aluminium and iron. Nevertheless, about 2% of the hydrogen ions from the sulfuric acid were still present, which resulted in a stream pH of 4.0. In the lake, the pH was 4.4, and the concentrations of all major cations and anions were significantly lower than in the heavily affected stream. Mixing of the stream water with lake water, formation of aluminium-sulphate complexes and coprecipitation of Ca may explain the resulting concentrations of major ions in the lake.  相似文献