Effects of dietary moisture content of extruded diets on physical feed quality and nutritional response in Atlantic salmon (Salmo salar)     

M. Oehme  T.S. Aas  H.J. Olsen  M. Sørensen  M. Hillestad  Y. Li  T. Åsgård 《Aquaculture Nutrition》2014,20(4):451-465

Feeds in modern aquaculture must be of high physical quality to withstand mechanical impacts. However, physical quality of feed has been shown to affect nutritional responses. In this study, different physical feed qualities were created using different drying time. Effects on physical feed quality, feed intake, nutrient digestibility and growth in Atlantic salmon were investigated. Different drying times of four commercial‐like diets resulted in dry matter contents of 95.9%, 94.1%, 92.3% and 90.8%. A fifth diet containing 70% dry matter was made by soaking pellets. Triplicate groups of Atlantic salmon (961 ± 12.1 g ind^?1, mean ± SEM) were first fed ad libitum and thereafter a restricted ration. The diets differed significantly in bulk density, DORIS durability, hardness, water stability after 60 and 120 min, but not in water stability after 240 min. Feed intake and growth were not affected by physical quality of the dry diets, whereas soaking had a positive effect on feed intake. Restricted compared with ad libitum feeding increased nutrient digestibility, but digestibility was not affected by varying drying time among diets. However, soaking resulted in slightly reduced digestibility of starch. Most methods used to analyse physical quality did not correlate with feed intake and growth; only long‐term water stability affected feed intake.  相似文献   

Effects of diet supplementation of soya‐saponins,isoflavones and phytosterols on Atlantic salmon (Salmo salar,L) fry fed from start‐feeding          下载免费PDF全文

M. Gu  J.N. Gu  M. Penn  A.M. Bakke  I. Lein  Å. Krogdahl 《Aquaculture Nutrition》2015,21(5):604-613

A 14‐week trial was conducted to investigate the effects of antinutritional factors (ANFs) commonly present in soybean ingredients, singly and in combination, on Atlantic salmon (Salmo salar L.) fed from start‐feeding. The experimental diets consisted of a negative control fish meal diet (FM), and a positive control diet with 167 g kg^?1 soybean meal inclusion (SBM) and four diets based on the FM diet supplemented with 2 g kg^?1 soya‐saponins (SAP), 1.5 g kg^?1 isoflavones (IFL), 0.3 g kg^?1 phytosterols (PHS) or a mixture of these (MIX). Fish fed the SAP diet showed significantly higher growth performance than those fed FM, while the IFL treatment significantly decreased growth performance of salmon fry. Fish fed the IFL diet had significantly lower maltase activity and higher trypsin activity in proximal intestine than fish fed the FM diet. Histological differences were observed in the liver of fish fed the IFL diet, characterized by reduced size of the hepatocytes. Fish fed the PHS and IFL diets showed the highest frequencies of skeletal deformities among the six treatments. In conclusion, the results indicate that purified isoflavones may negatively affect growth performance, intestinal function, liver metabolism and bone formation of salmon fry.  相似文献   

Mapping resistance to the bird cherry‐oat aphid (Rhopalosiphum padi) in barley     

W. Y. Cheung  L. Di Giorgio  I. Åhman 《Plant Breeding》2010,129(6):637-646

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Effects of non-native spruce plantations on small mammal communities in subarctic birch forests     

Åshild Ø. Pedersen  Nigel G. Yoccoz  Rolf A. Ims  Therese Sigurdsen 《Forest Ecology and Management》2010

Voles and shrews are key species in northern forest ecosystems. Thus, it is important to quantify to what extent new forestry practices such as planting of non-native tree species impact these small mammals. In northern Norway stands of coastal subarctic birch forests have increasingly been converted to non-native spruce stands during the last century. This leads to changes in the forest floor vegetation and soil conditions that can be expected to negatively impact the community of ground-dwelling small mammals. In this 10-year trapping study we contrasted seasonal small mammal population abundances in spruce plantations with four birch forest varieties. Six different small mammal species were trapped (in descending order of abundance; common shrew Sorex araneus, red vole Myodes rutilus, field vole Microtus agrestis, grey-sided vole M. rufocanus, pygmy shrew S. minutus and water shrew Neomys fodiens). None of the voles appeared to exhibit temporal dynamics resembling population cycles. The three most numerous species were clearly less abundant in the spruce plantations compared to the other forest types. Autumn abundances were most impacted by spruce plantations, indicating that growth rates in the reproductive season were more influenced than winter declines. Species associated with productive forest habitats (i.e. field vole and common shrew) were most impacted by tree species conversion. Still young spruce plantations inter-mixed with birch trees and the ecotone habitat, sustained small mammal abundances comparable to the native birch forests. This implies that managing spruce plantations to maintain a mix of different tree species and high spatial heterogeneity (i.e. more ecotones), will reduce the negative impacts on the small mammal community. On the contrary, if young spruce plantations, as they age become spruce monocultures covering larger parts of the landscapes than they do presently, the negative effects on small mammal communities may be larger than observed in the present study.  相似文献   

Results of allergen‐specific immunotherapy in atopic dogs with Malassezia hypersensitivity: a retrospective study of 16 cases          下载免费PDF全文

Liselotte Åberg  Katarina Varjonen  Susanne Åhman 《Veterinary dermatology》2017,28(6):633-e157

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Level up or game over: the implications of levels of impact in certification schemes for salmon aquaculture     

Vilde Steiro Amundsen  Asle Årthun Gauteplass  Jennifer Leigh Bailey 《Aquaculture Economics & Management (Blackwell Science)》2019,23(3):237-253

Abstract

Certification schemes are becoming increasingly important within aquaculture management, but the indicators that are used by these schemes are subject to considerable debate. Many have questioned their actual impact on improving the industry, and whether they effectively address the many externalities of aquaculture production. In this paper, we study the choice of indicators in eight major certification scheme standards for salmon aquaculture and examine to what degree they manage to address impacts beyond individual production sites. We find that, in accordance with the criticism, the majority of indicators pertain only to the site-level. However, indicators related to traceability, and to coordination and sharing of information among producers can elevate local concerns to a higher level of impact. We, therefore, argue that among all the certification scheme standards considered here, these types of indicators should be emphasized to a larger extent.  相似文献   

Effects of hyperoxia on behavioural and physiological variables in farmed Atlantic salmon (Salmo salar) parr     

Åsa Maria Espmark  Grete Baeverfjord 《Aquaculture International》2009,17(4):341-353

A controlled experiment mimicking Atlantic salmon (Salmo salar) pre-smolt farming conditions showed that fish exposed to 150 and 175% super oxygenated water produced higher levels of carbon dioxide with the subsequent decrease in water pH compared to control fish exposed to 100% O₂. At the 7th day of exposure the hyperoxic fish showed larger individual variation in swimming activity compared to the controls. The individual variance in activity, tail beat frequency and scattering in the tanks among super oxygenated fish decreased from the 7th to the 21st day of exposure. The behavioural effects of hyperoxia were seen in relation to altered feed consumption halfway through the experiment, lower body weight, and altered haematological variables at day 21 of exposure. Plasma chloride was reduced in the exposed fish and haemoglobin decreased with increasing oxygen saturations. Plasma cortisol was elevated only in the 150% oxygenated group at day 21, while no effect on osmolality was recorded. The alterations in physiology and behaviour from day 7 to day 21 may be explained in terms of acclimation to increased oxygen saturations. This study shows that behaviour may be used as an indication of impaired water quality that may influence animal welfare negatively and eventually prevent an efficient production.  相似文献   

The Potential of High-Oil Oats under Cool Temperate Conditions     

Åsmund Bj⊘rnstad  Knut Aastveit  Kjell Sverre Thoresen 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(4):219-225

Abstract

Genetic and growth temperature effects on the oil content of oats have been studied. A line with high oil content was crossed to a line with low oil content, and the progenies from parental and F₂ plants were studied in two replicated experiments, one in the field, the other combined field/greenhouse. Interactions between greenhouse and field were found for oil content as well as for other characters. High heritability estimates and additive gene action were found for oil content. Insignificant genetic correlations were found between oil content and grain yield. F₃ families which on average had the same oil content as the highest parent were recovered. The results from two independent phytotron experiments indicate that genes conferring high oil content and low temperatures during grain filling seem to work additively towards higher oil content.  相似文献   

Antinociceptive effect of buprenorphine and evaluation of the nociceptive withdrawal reflex in foals          下载免费PDF全文

Åse I Risberg  Claudia Spadavecchia  Birgit Ranheim  Eli HS Hendrickson  Andreas Lervik  Henning A Haga 《Veterinary anaesthesia and analgesia》2015,42(3):329-338

ObjectiveTo elicit and evaluate the NWR (nociceptive withdrawal reflex) in 2 and 11 day old foals, to investigate if buprenorphine causes antinociception and determine if the NWR response changes with increasing age. The effect of buprenorphine on behaviour was also evaluated.Study designProspective, experimental cross-over trial.AnimalsNine Norwegian Fjord research foals.MethodsBuprenorphine, 10 μg kg⁻¹ was administered intramuscularly (IM) to the same foal at 2 days and at 11 days of age. The NWR and the effect of buprenorphine were evaluated by electromyograms recorded from the left deltoid muscle following electrical stimulation of the left lateral palmar nerve at the level of the pastern. Mentation, locomotor activity and respiratory rate were recorded before and after buprenorphine administration.ResultsWe were able to evoke the NWR and temporal summation in foals using this model. Buprenorphine decreased the root mean square amplitude following single electrical stimulation (p < 0.001) in both age groups, and increased the NWR threshold following single electrical stimulation in 2 day old foals (p = 0.0012). Repeated electrical stimulation at 2 Hz was more effective to elicit temporal summation compared to 5 Hz (p < 0.001). No effect of age upon the NWR threshold was found (p = 0.34). Sedation when left undisturbed (11 occasions), increased locomotor activity when handled (9 occasions) and tachypnea (13 occasions) were common side-effects of buprenorphine.Conclusion and clinical relevanceThese findings indicate that buprenorphine has antinociceptive effect in foals. Opioid side effects often recognized in adult horses also occur in foals.  相似文献   

Field population development of bird cherry-oat aphid and greenbug (Hemiptera: Aphididae) on wheat-alien substitution and translocation lines     

L. A. Crespo-Herrera  R. P. Singh  I. Åhman 《Euphytica》2015,203(2):249-260

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