- Børge Damsgård chairing the session
At the SEAFOODplus session nine presentations highlighted interesting results from the project. AQUA2006 concentrates on aquaculture, but the SEAFOODplus presentations were selected from different RTD areas, showing the integration of aquaculture research between and among the various SEAFOODplus projects. Below please find the abstracts for the presentations, and the pdf files showing what was presented. Dr. Børge Damsgård, the coordinator of the research within the RTD area 6 was the chairman for the SEAFOODplus session. Participants were free to choose any of the lectures for listening, but it was estimated that an average of 100 people attended the session.
How SEAFOODplus integrates aquaculture research in the total food chain
Torger Børresen, SEAFOODplus Coordinator, Danish Institute for Fisheries Research
SEAFOODplus is an integrated project supported by the European Union under Priority 5, Food Quality and Safety of the 6th Framework Programme. The project covers the total food chain within the seafood area and comprises six major research themes. One of these contains aquaculture research. However, the activities have to be seen in a total food chain perspective under a concept where the consumer health and wellbeing sets the priority for the research topics. In addition to aquaculture the SEAFOODplus project contains human nutrition, consumer studies, seafood quality, seafood products and traceability as the other major research themes. Many links have been established between the research within the aquaculture area and the other research themes of SEAFOODplus and it is ascertained that the aquaculture products will be safe, nutritious and of a high eating quality suitable for European consumers such that health and wellbeing may be improved. Examples will be given on how quality traits are being considered in the farming situation as well as in the final products to be marketed.
Consumer behaviour and preference for aquaculture products
Karen Brunsø*, Joachim Scholderer, Wim Verbeke, and Svein Ottar Olsen
*MAPP, Aarhus School of Business, Denmark
During the last decades, the proportion of aquaculture products in the market place has increased dramatically and this trend seems to continue in the future as well. While both the producers of aquaculture products as well as the distribution channels are aware of this change in product composition, still little is known about the effect this has on consumer preferences and product choices. In connection with the SEAFOODplus project CONSUMERSURVEY, which aims at explaining seafood consumption, a major survey has been carried out in five European countries in order to achieve more knowledge about consumer preferences and choice in relation to fish in general as well as preferences for farmed and wild fish. Questionnaires were sent to a representative sample of consumers in 5 European countries: Denmark, Belgium, Netherlands, Poland and Spain, and a total of 4786 valid questionnaires were returned and analysed. Results show that there is widespread confusion regarding whether fish is wild or farmed. The data disclose large discrepancies in reported total fish consumption frequency and reported consumption of wild and farmed fish.
From the total sample, 2.5% claim to never or seldom eat fish in general. About one third claim never to eat farmed fish, and also one third claims never to eat wild fish. Combining these, it turns out that 24.8% of the total sample claim neither to eat farmed nor wild fish. It seems, however, that the confusion about wild and farmed fish increases with age, since the reported consumption of wild fish decreases with increasing age, which is the opposite trend compared to reported overall fish consumption. The data shows that on average the consumption of fish increases with increasing age in all countries except Poland where differences in consumption frequencies were not significant across age groups.
On average fresh wild fish is perceived to be of higher quality compared to farmed fish. On the other hand, fresh farmed fish is perceived to have a more consistent quality compared to fresh wild fish and to be more available and thus easier to purchase. Furthermore, when it comes to safety, consumers do not perceive any difference in relation to the safety of fresh wild fish and fresh farmed fish.
Providing information to consumers about the farmed or wild origin of fish
Wim Verbeke*, Karen Brunsø, Joachim Scholderer and Svein Ottar Olsen
*Department of Agricultural Economics, Ghent University, Belgium
Fish supply from aquaculture responds to the increasing demand for a healthy food, and fills gaps left by depleting natural fish stocks. Whereas several studies have previously focused on consumer perception of fish in general, only a few have recently focused on specific perceptions of wild and/versus farmed fish. One of these studies is the CONSUMER SURVEY project within the EU FP6 Integrated Project SEAFOODplus. Together with the main survey aiming at explaining seafood consumption and understanding consumer motives and barriers, substantial data were also collected about knowledge, use of and trust in information sources, and interest in information cues. Consumer knowledge about and interest in the farmed or wild origin of fish received particular attention in this survey. Consumer samples were representative for age in region in Belgium, the Netherlands, Denmark, Spain and Poland (total n=4,786). Insights in consumer knowledge and information needs will yield recommendations for information provision that aims at bridging some of the existing gaps between consumer perception and scientific reality about farmed versus wild fish.
With respect to objective knowledge about fish, a specific item pertained to “More than half of the fish we buy is farmed fish”. From the total sample, 44.8% of the respondents provided the correct ‘no’ answer. This correct response percentage was the lowest, and it was provided with the highest degree of uncertainty, as compared to other objective knowledge items in the questionnaire. As shown in the presentation, large differences between the countries were observed.
Indications about capture area received the lowest degree of attention on fish labels, and interest in potential information about the wild or farmed origin of fish ranked only ninth in a list of 13 potential information cues. Top interest levels were reserved for safety guarantee and quality mark. Apparently, consumers are unfamiliar and feel uneasy about information dealing with fish origin; most probably, lack of past experience with this information cue hinders consumers to form quality expectations that are confirmed by perceived quality performance upon use.
Although consumers in general show little apparent interest in information about the farmed or wild origin of fish, the analyses reveal specific consumer segments with heightened interest in information about fish origin.
Endocrine control and tailor-made seafood
(full presentation not available)
Björn Thrandur Björnsson* and Elisabeth Jönsson, Göteborg University, Sweden
In Western perspective, aquaculture of most species is still a young industry, essentially dealing with raising wild animals in captivity. The founder generations have been chosen with various degree of stock selection, from none to fairly extensive, and subsequent generations have been subjected to equally varying degree of selection.
Such selection has often focused on basic physical traits with high heritability, such as growth rate in salmonids, and this has already made a marked impact on the aquacultured phenotype. Other traits, especially those linked to quality, have received less attention in selection programs. Quality traits are often highly complex, being the end results of a number of physiological processes, each of which may be regulated by various hormones. A better understanding of the biological basis for quality traits is therefore of great importance in order to successfully produce tailor-made seafood in a predictable way.
An important approach to producing tailor-made seafood is to control physiological processes by environmental manipulation. However, in order to make this approach effective, we need to understand how endocrine systems are affected by environmental parameters, and how these in turn regulate physiological processes, in essence translating environmental changes into changes in quality traits. In addition, as physiological processes and their endocrine control are ultimately ruled by gene expression, a second approach is to exploit the genetic variation within and among populations. However, for the selection of quality traits to be effective, we need more knowledge on the genetic basis of the endocrine and physiological systems.
As an illustration, a level of muscular adiposity can be taken as a quality trait in aquacultured salmonids. Manipulation of a broad set of environmental variables such as density, flow rate, temperature, light conditions and feeding regimes is likely to affect adiposity. Similarly, breeding selection can be used change the level of adiposity. However, as long as the endocrine and physiological mechanisms behind adiposity in fish are not well understood, this quality trait remains a “black box”. Manipulation, through environmental control or breeding selection, aimed at changing adiposity may well result in adverse effects on other important aquaculture traits, e.g. skeletal growth or onset of puberty, as long as the biological cause-effect relationships are not known.
Currently, our research within the SEAFOODplus/BIOQUAL project focuses on understanding how ghrelin regulates appetite and energy balance in salmonids and how this newly discovered hormone interacts with the growth hormone – insulin-like growth factor I system and its regulation of growth and metabolism.
Mechanisms behind texture changes of aquaculture products
Helene Godiksen* and Flemming Jessen, Danish Institute for Fisheries Research
The texture of fish is a very important quality characteristic. However problems such as soft texture and gaping are frequently observed in aquacultured fish resulting in reduced yield and undesirable quality. Texture problems cannot be reversed but are carried on to processed fish product such as smoked salmon and frozen fillets. Different investigations have shown that muscle texture, measured as raw fillet hardness, varies with biological factors including muscle fat content (Morkore et al., 2001) fat distribution (Andersen et al., 1997), size of fish and muscle cellularity (Johnston et al., 2000). Farming condition such as feeding regime, diet (de Francesco et al., 2004), water quality and stress before slaughter (Sigholt et al., 1997) have also been reported to correlate with texture changes. Furthermore, industrial practices such as slaughter method and subsequent storage conditions have significant effect on texture (Sigholt et al., 1997). Despite awareness of the effect such factors have on texture the responsible mechanisms remain elusive.
Several authors have stressed the significance of proteolytic enzymes as key factors in the changes of fish muscle post mortem. The lysosomal cathepsins have been suggested as main contributors to softening of fish muscle. These enzymes are active at the low postmortem pH and it is likely that they function in synergy to break down the structural proteins (Delbarre-Ladrat et al., 2004). Although there has been a generally agreement that the role of calpain is much less pronounced in fish than in mammals, recent studies showed accelerated muscle softening by calcium activation of calpain (Salem et al., 2004). In addition, it has been suggested that the ratio between calpain and its endogen inhibitor calpastatin should be considered as an important factor in postmortem proteolysis (Salem et al., 2005). The metalloproteinases have also been suggested to play a role in development of soft tissue by degradation of collagen (Kimiya et al., 2005) however the importance of these enzymes is not evident. Proteasome activity has been related to fish growth and feeding regime (Martin et al. 2002) but further studies are needed to decide the importance of this enzyme. In conclusion, our understanding of the complex mechanisms of texture development in fish is not complete, but it is expected that several proteolytic enzymes are involved acting in synergy on the cell structural proteins.
Andersen U.B. et al. 1997. J. Sci. Food Agric. 74, 347-353.
Delbarre-Ladrat C. et al. 2004. Food Chem. 88, 389-395.
Francesco M. et al. 2004. Aquaculture 236, 413-429.
Johnston I.A. et al. 2000. Aquaculture 189, 335-349.
Kimiya T. et al. 2005. Fisheries Sci. 71, 672-678.
Martin S.A.M. et al. 2002. Plugers Arch. Eur. J. Physiol. 445, 257-266.
Morkore T. et al. 2001. J. Food Sci. 66(9), 1348-1354.
Coping strategies, husbandry systems and ethical quality in aquaculture
Sunil Kadri* and Felicity A. Huntingford, Glasgow University, Scotland
The “ethical quality” of fish produced in aquaculture systems is important to modern fish production. This is largely due to increasing public concern and anticipated regulatory changes, but also because the welfare standards by which a fish is reared and then slaughtered may produce an impact upon both production and flesh quality. These factors have led to considerable interest both in indices of good welfare and in development of production systems or technologies that promote it. Such indices and systems are known to be species-specific, but behavioural variation within species is also very important in this context, the topic of this presentation.
As part of the ETHIQUAL project within Seafood Plus, studies are being performed on a species from Northern, Southern and Eastern Europe. These studies are providing increasing evidence for the existence of coping strategies (consistent individual differences in behavioural and physiology responses to stressors) several species of cultured fish; including common carp, Atlantic cod and European sea bass. Figure 1 illustrates variaton in behavioural and physiological responses to stress in common carp. Such variation within populations implies that the impact of a given husbandry practice, for example feeding regime, on welfare may vary between individual fish. Results from these studies will be presented and discussed in terms of their implications for welfare of cultured fishes.
The existence of different coping strategies among cultured fish makes the ideal of good welfare for all individuals in a population difficult to achieve, since much current husbandry practice and most regulatory schemes, imposing or requiring uniform conditions for all individual of a given species/life history stage. However, relatively simple and economically feasible changes in husbandry practice can enhance welfare as well as production. Examples of these will be presented to illustrate the types of husbandry measures which might be used to accommodate these differences within cultured fish populations.
SmartTag technology for monitoring fish welfare in aquaculture
Øyvind Aas-Hansen* and Børge Damsgård, Norwegian Institute of Fisheries and Aquaculture Research
Telemetric measurements of ventilation represent the perhaps most promising physiological indicator of a wide range of important welfare factors in today’s aquaculture industry. Based on existing scientific literature, it is known that ventilation responds to factors such as hypoxia, hypercarbia, and changes in water pH and metabolite levels, fear, pain and handling stress.
As part of the integrated EU-funded research project SEAFOODplus, we have developed a concept for the use of physiological telemetry as a method for the assessment and documentation of fish welfare in aquaculture research. This involves the construction of an ultrasound acoustic electronic tag termed SmartTag which is attached externally to a statistically appropriate sub-sample of the fish, and provides online measurements of changes in water pressure within the buccal cavity, providing detailed information of the fish’s ventilation. Thus, rather than monitoring properties of the rearing environment such as water quality parameters or other potential sources of distress, the SmartTag enables measurements of how the rearing environment affects the physiology of individual, free-swimming fish.
SmartTag prototypes have been successfully tested in sea cages and indoor tanks. We are also performing a series of validation experiments, including the use of swim tunnel respirometry and water quality manipulation
So far, SmartTag function as a very promising tool in fish welfare research. Potentially, further development of the SmartTag concept may justify its use also as a tool for monitoring and documenting fish welfare research in commercial aquaculture. In particular, this latter aspect may prove more important in the future, along with the development of larger fish production units with increasing number of fish, and the increased prevalence of submerged- and offshore aquaculture facilities where the opportunities for continuous supervision is limited and the need for a remote early-warning system therefore is greater.
Transport of turbot (Psetta maxima): Effect on blood parameters and product quality
Hans van de Vis*, Marie Champod, Henny Reimert and Bert Lambooij
*IMARES, Ijmuiden, The Netherlands
Since the last decades, governments, farmers and processors of fish and welfare and consumers’ associations have become increasingly concerned about welfare of finfish. Transport, which is part of the pre-slaughter procedures, is of particular interest in the context of European projects. For warm-blooded animals it has already been shown that transport is stressful and this has consequences for the quality of the product. For fish has been demonstrated that short-term stress, including transport, has effects on ante mortem and post mortem physiology.
The objective of the study was to establish effects of transport on farmed turbot (Psetta maxima) on blood parameters and fish flesh quality at the premises of a fish farm.
Stress caused by transport on turbot was studied with 100 turbots in the first experiment and 180 fishes in the second experiment. In both experiments half of the total number of fishes used was transported. The remaining fishes were analysed at the premises of a fish farm. Effect of transport on blood biochemistry was studied by analysis of cortisol, glucose, D- and L-lactate and free fatty acids. For both experiments the onset and resolution of rigor mortis were analysed by measurement of rigor index values. Some of the fish flesh quality traits (pH and colour changes) were only studied for the second experiment.
For the first experiment it was observed that transport may lead to increased levels of cortisol, glucose, d- and l-lactate and a decrease for free fatty acids. Contrary to our expectations, transport of turbot in the second experiment did not result in an increase of blood plasma levels of cortisol
For the first experiment a significant effect of transport on onset and resolution of rigor mortis in turbot was observed. After 75 h of storage rigor index values were significantly higher for the transported batch, compared to the not transported one. The rigor index curve leveled off at approximately 80% for both the transported and not transported batch.
For the second experiment resolution of rigor mortis may have been complete, as rigor index values of 22% were obtained for the transported and not transported batch.
With respect to pH values, which were obtained in the second experiment, we observed that the values for the transported batch were significantly higher than for the not transported one. At the start of this experiment 90 fishes were taken out of the fasting tank and placed separately in a tub for transport. The remaining 90 fishes of. the not transported batch in the fasting tank were caught with a hand net for analysis of blood chemistry, pH and colour. The handling of the remaining 90 fishes was not interrupted by transport for 2 h. This interruption may have, unintentionally, resulted in a recovery period for the turbots and therefore pH values were higher for the transported batch, compared to the not transported one. The interruption of the handling stress may also have influenced the lightness (L*) of the fillets. For the not transported batch the values may have been significantly higher, compared to the transported one.
In conclusion it can be stated that transport may influence blood chemistry in turbot and handling stress may mask effects of transport on product quality parameters.
A Canadian-Norwegian collaborative approach to fish health and welfare issues
Shannon K. Balfry*, Hilde Toften, Erling Sandsdalen, Robert Scott McKinley and Børge Damsgård
*University of British Columbia, Vancouver, Canada
Norway and Canada share similar concerns and needs related to the health and well-being of cultured finfish. As a result, fish health specialists from Canada’s Networks of Centres of Excellence – AquaNet, and Fiskeriforskning have agreed to an exchange of scientists and student to address issues related to the ‘in-situ’ measurement of stress in free swimming fish, welfare indicators, protocols for the early detection of disease, and the development and evaluation of vaccines. The collaboration has evolved over the last three years through the establishment of annual joint research forums to highlight areas of common interest and methodological approaches in the area of fish health and welfare.
To date, examples of joint fish health and welfare projects include a three year project funded by the Norwegian Research Council, entitled “Use of saline water in intensive smolt production: effects on health, welfare and risk of winter ulcer”. This research project is designed to examine the problems with winter ulcer in farmed Atlantic salmon in Norwegian hatcheries, and has important implications for Canadian hatcheries that have similar problems with fungal infections. This collaborative research project has recently been completed and the results will be discussed in this presentation. A second example includes an AquaNet funded research project to develop and evaluate new diagnostic tools for early detection of infectious hematopoietic necrosis virus (IHNv) and infectious salmon anemia virus (ISAv) in farmed and wild Atlantic salmon.