Fjelldal P.G.,Norwegian Institute of Marine Research |
Hansen T.,Norwegian Institute of Marine Research |
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.
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.
Van Wezemael L.,Ghent University |
De Smet S.,Ghent University |
Ueland T.,Nofima |
Verbeke W.,Ghent University
Meat Science | Year: 2014
The supply of tender beef is an important challenge for the beef industry. Knowledge about the profile of consumers who are more optimistic or more accurate in their tenderness evaluations is important for product development and beef marketing purposes. Central location tests of beef steaks were performed in Norway and Belgium (n= 218). Instrumental and sensorial tenderness of three muscles from Belgian Blue and Norwegian Red cattle was reported. Consumers who are optimistically evaluating tenderness were found to be more often male, less food neophobic, more positive towards beef healthiness, and showed fewer concerns about beef safety. No clear profile emerged for consumers who assessed tenderness similar to shear force measurements, which suggests that tenderness is mainly evaluated subjectively. The results imply a window of opportunities in tenderness improvements, and allow targeting a market segment which is less critical towards beef tenderness. © 2013 Elsevier Ltd.
Kimiya T.,Japan National Research Institute of Fisheries Science |
Sivertsen A.H.,Nofima |
Journal of Food Engineering | Year: 2013
Visible/near-infrared spectroscopy has been evaluated for use in freshness prediction and frozen-thawed classification of farmed Atlantic salmon fillets, where fresh samples were stored as whole fish in ice. A handheld interactance probe for performing rapid measurements of single fillets and an imaging spectrometer for online analysis at an industrial speed of one fillet per second, have been used. Freshness as storage days in ice is predicted with an accuracy of 2.4 days for individual fillets, whereas frozen-thawed salmon fillets are completely separated from fresh fillets. The prediction results are comparable to previous results using the Quality Index Method with trained panelists. The region between 605 and 735 nm, which excludes interference by carotenoids and water, is appropriate for both frozen-thawed classification and freshness prediction of salmon fillets. The results indicate that the spectral changes are explained mainly by oxidation of heme proteins during the freeze-thaw cycle and during chilled storage in ice. © 2013 Elsevier Ltd.
Gjedrem T.,Nofima |
Gjedrem T.,Akvaforsk |
Robinson N.,Nofima |
Aquaculture | Year: 2012
Aquaculture is the fastest growing food production industry, and the vast majority of aquaculture products are derived from Asia. The quantity of aquaculture products directly consumed is now greater than that resulting from conventional fisheries. The nutritional value of aquatic products compares favourably with meat from farm animals because they are rich in micronutrients and contain high levels of healthy omega-3 fatty acids. Compared with farm animals, fish are more efficient converters of energy and protein. If the aquaculture sector continues to expand at its current rate, production will reach 132. million tonnes of fish and shellfish and 43. million tonnes of seaweed in 2020. Future potential for marine aquaculture production can be estimated based on the length of coastline, and for freshwater aquaculture from available land area in different countries. The average marine production in 2005 was 103. tonnes per km coastline, varying from 0 to 1721 (China). Freshwater aquaculture production in 2005 averaged 0.17. tonnes/ha, varying from 0 to close to 6. tonnes per ha (Bangladesh), also indicating potential to dramatically increase freshwater aquaculture output. Simple estimations indicate potential for a 20-fold increase in world aquaculture production. Limits imposed by the availability of feed resources would be lessened by growing more herbivorous species and by using more of genetically improved stocks.Aquaculture generally trails far behind plant and farm animal industries in utilizing selective breeding as a tool to improve the biological efficiency of production. It is estimated that at present less than 10% of aquaculture production is based on genetically improved stocks, despite the fact that annual genetic gains reported for aquatic species are substantially higher than that of farm animals. With an average genetic gain in growth rate of 12.5% per generation, production may be dramatically increased if genetically improved animals are used. Importantly, animals selected for faster growth have also been shown to have improved feed conversion and higher survival, implying that increased use of selectively bred stocks leads to better utilization of limited resources such as feed, labour, water, and available land and sea areas. © 2012 Elsevier B.V.
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.
Genetics, selection, evolution : GSE | Year: 2012
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. 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. 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. 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.
James P.,Nofima |
Aquaculture | Year: 2012
A series of experiments were undertaken to determine the effects of continuous (fed weekly) and intermittent (1. week fed/starve; 2. week fed/starve; 4. week fed/starve) feeding regimes on three size classes of Strongylocentrotus droebachiensis (initial average size: SC1, 4.1. mm; SC2, 17.5. mm; SC3, 38.4. mm) fed a manufactured sea urchin diet. In the continuous feed treatment, urchins were fed once per week ad libitum so feed was always available. In the intermittent feed treatments, urchins were fed ad libitum during the 'feed' period and all feed was removed during the 'starve' period. The experiments ran for either 9. months (SC1) or 12. months (SC2 and SC3). The feed treatments had no effect on sea urchin survival (100% regardless of size class or treatment) over the experimental period. The urchins fed weekly had the highest absolute growth in each size class but the differences were more apparent in the small size class (SC1). The 1. week fed/starve treatment had the lowest FCR values in SC1 and SC2 but there was no significant difference between feed treatments in SC3. Urchins in SC1 and SC2 fed weekly had higher GI values than the other feed treatments but in the large size class (SC3) there were no differences in the GI value at the conclusion of the experiment regardless of the feed treatment. The only difference in the reproductive stage of the urchins at the conclusion of the experiments (between feed treatments) was in the medium size class where urchin fed the 4. week fed/starve treatment had a higher percentage of animals (50%) in Stage 3 than the other feed treatments (30%). This study shows that extended periods (up to 4. weeks) of intermittent feeding had a limited effect on somatic growth of larger urchins (SC2 and SC3) but smaller urchins (SC1) grew significantly larger with regular feeding. However, the FCR was significantly lower in the urchins of the 1. week fed/starve treatment in SC1 and SC2 and the 50% reduction in labour costs and reduction of the amount of feed required offered by this feed regime are likely to be optimal for grow-out of juvenile urchins despite the reduced absolute growth. In the case of larger sea urchins (SC3) there was no effect on gonadal growth from the various feeding regimes indicating that intermittent feed periods of up to 4. weeks will not adversely affect gonad enhancement operations but will substantially reduce feed and labour costs. These results should be carefully considered in order to optimise feed regimes for future sea urchin on-growing and gonad enhancement ventures. © 2012.
Siikavuopio S.I.,Nofima |
Aquaculture Research | Year: 2015
The current study investigates whether it is possible to increase the meat content of captive male king crab (Paralithodes camtschaticus) (average = 2.2 kg) by feeding manufactured diets at different temperatures (4°C, 8°C and 12°C). A 110 days trial was undertaken with groups of male king crabs held in 12 land-based holding tanks. All crabs survival in the lowest temperature treatment, one animal died in the medium-temperature group (8°C) and four animals in the highest temperature treatment (12°C). The results showed that feed intake increased with increasing temperature from an average of 1.0 g kg-1 day-1 at 4°C to 2.8 g kg-1 day-1 crab at 12°C. The percentage meat content was significantly higher at the final census (60.0%) compared with the initial census (37.5%) in all temperature groups, but there were no significant differences in the percentage meat content of the king crabs held in the different temperature treatments at the conclusion of the experiment. Oxygen consumption was also significantly affected by temperature and increased with increasing temperature. The results of the experiment show that the optimal temperature to maintain, and enhance, the meat content of king crab is close to 4°C. © 2015 John Wiley & Sons Ltd.
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.