Time filter

Source Type


Odegard J.,NOFIMA | Odegard J.,Norwegian University of Life Sciences | Meuwissen T.H.E.,Norwegian University of Life Sciences
Genetics Selection Evolution | Year: 2012

Background: In classical pedigree-based analysis, additive genetic variance is estimated from between-family variation, which requires the existence of larger phenotyped and pedigreed populations involving numerous families (parents). However, estimation is often complicated by confounding of genetic and environmental family effects, with the latter typically occurring among full-sibs. For this reason, genetic variance is often inferred based on covariance among more distant relatives, which reduces the power of the analysis. This simulation study shows that genome-wide identity-by-descent sharing among close relatives can be used to quantify additive genetic variance solely from within-family variation using data on extremely small family samples. Methods. Identity-by-descent relationships among full-sibs were simulated assuming a genome size similar to that of humans (effective number of loci ∼80). Genetic variance was estimated from phenotypic data assuming that genomic identity-by-descent relationships could be accurately re-created using information from genome-wide markers. The results were compared with standard pedigree-based genetic analysis. Results: For a polygenic trait and a given number of phenotypes, the most accurate estimates of genetic variance were based on data from a single large full-sib family only. Compared with classical pedigree-based analysis, the proposed method is more robust to selection among parents and for confounding of environmental and genetic effects. Furthermore, in some cases, satisfactory results can be achieved even with less ideal data structures, i.e., for selectively genotyped data and for traits for which the genetic variance is largely under the control of a few major genes. Conclusions: Estimation of genetic variance using genomic identity-by-descent relationships is especially useful for studies aiming at estimating additive genetic variance of highly fecund species, using data from small populations with limited pedigree information and/or few available parents, i.e., parents originating from non-pedigreed or even wild populations. © 2012 degård and Meuwissen; licensee BioMed Central Ltd. Source

Fjelldal P.G.,Norwegian Institute of Marine Research | Hansen T.,Norwegian Institute of Marine Research | Albrektsen S.,NOFIMA
Aquaculture | Year: 2012

In order to study the short-term effects of dietary P levels during juvenile rearing on mineral status (bone ash content), and its long-term effects on the development of vertebral deformities (radiography and external examination), triplicate groups of Atlantic salmon juveniles (1.3g) were fed blue whiting meal (67%) based diets added 0 (0P), 3 (3P) and 6 (6P) g inorganic P kg-1 (15, 18 or 21gkg-1 total P) for 77days (18.3g), and then followed up on a common commercial diet for 432days (1927g). At the termination of the period on the experimental feeds the vertebrae of the fish fed the 0P diet had a significantly lower ash weight than those fed the 3P and 6P diets, while there was no difference in the occurrence of radiological deformed fish. 252days later, the 0P (31.7±5.5%) dietary group had a significant higher occurrence of radiological deformed fish than the 6P dietary group (9.4±5.6%), while the 3P dietary group displayed an intermediate level (19.7±2.8%). At termination, 432days after the termination of the experimental feeds, the 0P dietary group (5.9±0.7%) had a significantly higher prevalence of externally deformed fish compared to the 3P (3.5±0.9%) and 6P (2.0±0.4%) dietary groups. This was mainly caused by a higher level of deformities in the caudal region (V31-58) of the vertebral column in the 0P group. There were no effects on mortality or growth of the present diets.The results show that inadequate P nutrition in a short period during the juvenile stage can predispose Atlantic salmon to develop vertebral deformities following seawater transfer. © 2012 Elsevier B.V. Source

Larsen H.,NOFIMA
Acta Horticulturae | Year: 2012

The storability and shelf life of plums is limited by physiological and fungal decay and softening. Preharvest factors making the fruit firmer and less susceptible to decay include orchard management, nutritional status and plant protection programme. Gibberellic acid treatment is widely used in sweet cherry growing to improve fruit size and firmness. Spraying plum trees with gibberellic acid three weeks prior to harvest showed similar effects. In treated trees the fruits were larger and the fruit quality was improved. Norwegian plums are grown close to the market. The growers are recommended to pick the plums close to eating ripe. The fruit quality will be very good, however, immediate cooling and unbroken cool chain from orchard to consumer is important to avoid losses during marketing. Norwegian plums are marketed in consumer packages with a plastic film cover. Using a laser perforated plastic film, a modified atmosphere was obtained. The plums kept firmer and greener. However, the losses due to fungal decay were not acceptable for commercial use. Additional treatments (heating, dipping in calcium etc.) improve the storability and shelf life. Storage of plums in controlled atmosphere (CA or ULO) with low oxygen (1-2%) and 2 to 6% CO2 may improve the storability of plums and prolong the marketing season up to eight weeks. Source

Van Wezemael L.,Ghent University | Ueland O.,NOFIMA | Verbeke W.,Ghent University
Meat Science | Year: 2011

Beef packaging can influence consumer perceptions of beef. Although consumer perceptions and acceptance are considered to be among the most limiting factors in the application of new technologies, there is a lack of knowledge about the acceptability to consumers of beef packaging systems aimed at improved safety. This paper explores European consumers' acceptance levels of different beef packaging technologies. An online consumer survey was conducted in five European countries (n= 2520). Acceptance levels among the sample ranged between 23% for packaging releasing preservative additives up to 73% for vacuum packaging. Factor analysis revealed that familiar packaging technologies were clearly preferred over non-familiar technologies. Four consumer segments were identified: the negative (31% of the sample), cautious (30%), conservative (17%) and enthusiast (22%) consumers, which were profiled based on their attitudes and beef consumption behaviour. Differences between consumer acceptance levels should be taken into account while optimising beef packaging and communicating its benefits. © 2011 Elsevier Ltd. Source

Rosendal G.K.,Fridtjof Nansen Institute | Olesen I.,NOFIMA | Tvedt M.W.,Fridtjof Nansen Institute
Aquaculture | Year: 2013

Thematuring aquaculture sector currently faces a number of challenges relating to the objectives of sustainability, conservation, equity and access to and legal protection of genetic resources. The study investigates, through interviews, howactors in the aquaculture sector perceive their optionswith a viewto accessing aquatic geneticmaterial and to protecting innovations in breeding. Moreover, the study analyses how corporate strategies, technological developments, and international regulatory regimes are perceived to affect these options, building also on scientific literature and other legal and policy documents. A methodology of descriptive and explorative case study within the qualitative domain is applied for this. Included are comparisons of findings from Norwegian case studies on Atlantic salmon and Atlantic cod with similar studies on marine shrimp in India and tilapia in South East Asia and Africa. Aquaculture is increasingly characterised by pressure toward higher production efficiency and short-term profits. Hence, actors in the aquaculture sector face emerging difficulties pertaining to affordable access to improved breeding material and technology, while also securing adequate funding for sustainable breeding programmes. Public ownership or support seems to be important measures to balance these objectives that may otherwise be hard to combine. This is particularly the case during the early phases of implementation and operation of applied aquaculture breeding programmes. An alternative model with cooperative/farmers' ownership is also worth considering in many situations, particularly after the first establishment phase. © 2013 Elsevier B.V. Source

Discover hidden collaborations