Linkage mapping, comparative genome analysis, and QTL detection for growth in a non-model teleost, the meagre Argyrosomus regius, using ddRAD sequencing

Meagre (Argyrosomus regius), is a benthopelagic species rapidly emerging in aquaculture, due to its low food to biomass conversion rate, good fillet yield and ease of production. Tracing a species genomic background along with describing the genetic basis of important traits can greatly influence both conservation strategies and production perspectives. In this study, we employed ddRAD sequencing of 266 fish from six F1 meagre families, to construct a high-density genetic map comprising 4529 polymorphic SNP markers. The QTL mapping analysis provided a genomic appreciation for the weight trait identifying a statistically significant QTL on linkage group 15 (LG15). The comparative genomics analysis with six teleost species revealed an evolutionarily conserved karyotype structure. The synteny observed, verified the already well-known fusion events of the three-spine stickleback genome, reinforced the evidence of reduced evolutionary distance of Sciaenids with the Sparidae family, reflected the evolutionary proximity with Dicentrarchus labrax, traced several putative chromosomal rearrangements and a prominent putative fusion event in meagre’s LG17. This study presents novel elements concerning the genome evolutionary history of a non-model teleost species recently adopted in aquaculture, starts to unravel the genetic basis of the species growth-related traits, and provides a high-density genetic map as a tool that can help to further establish meagre as a valuable resource for research and production.info:eu-repo/semantics/publishedVersio

A three-year longitudinal survey reveals early life infection of farmed gilthead sea bream (Sparus aurata) by Enterospora nucleophila (Microsporea: Enterocytozoonidae)

Trabajo presentado en el 15th International Conference of Parasitology, celebrado en Copenhague (Dinamarca) del 21 al 26 de agosto de 2022.[Introduction]: Emaciative microsporidiosis due to Enterospora nucleophila is considered an emerging problem in gilthead sea bream farming. Its main impact is the severe growth retardation, normally accompanied by sustained trickling mortality, which is only noticed with high intensity of infection. The aim of the current study was to assess the possible points of entry of this intestinal parasite into the farming facilities, by using qPCR screening in a longitudinal epidemiological survey. [Methods]: Fish were sampled at different critical control points during two production cycles in Spain (C1) and Greece (C2), involving 2 hatcheries, 3 nursery conditions, 4 pre-fattening facilities, and 5 sea cage farms with different entering seasons, from egg to commercial size. Artemia and rotifers were also analysed. [Results]: After analysing 1,930 samples, the microsporidium was found in all the farms, but not in all farming events. Fish were negative for the parasite from the egg to the fry stage just after weaning in all sampled hatcheries-nurseries, no matter what type of water rearing system was used. Live prey was also negative. The first positive cases were detected in C2 when entering the nursery vs when leaving the nursery in C1. The smallest fish harbouring the parasite weighed 0.9 g. Before stocking into the sea cages, the highest prevalence of infection (100 %) was detected in a pre-fattening facility in which fish spent a longer period than usually, with an open seawater flow, without filtering. The parasite was found in all sea cages with prevalence ranging from 10 to 72.4%. [Conclusions]: The ubiquitous presence of E. nucleophila in the farms emphasize the importance of incorporating its routine detection into the management and biosecurity protocols of farms. [Funding]: ParaFishControl H2020 EU project (634429)

Microbiota Succession of Whole and Filleted European Sea Bass (Dicentrarchus labrax) during Storage under Aerobic and MAP Conditions via 16S rRNA Gene High-Throughput Sequencing Approach

In the present work, the profiles of bacterial communities of whole and filleted European sea bass (Dicentrarchus labrax), during several storage temperatures (0, 4, 8 and 12 °C) under aerobic and Modified Atmosphere Packaging (MAP) conditions, were examined via the 16S rRNA High-Throughput Sequencing (HTS) approach. Sensorial attributes were also assessed to determine products’ shelf-life. Results indicated that shelf-life was strongly dependent on handling, as well as on temperature and atmosphere conditions. HTS revealed the undisputed dominance of Pseudomonas from the very beginning and throughout storage period in the majority of treatments. However, a slightly different microbiota profile was recorded in MAP-stored fillets at the middle stages of storage, which mainly referred to the sporadic appearance of some bacteria (e.g., Carnobacterium, Shewanella, etc.) that followed the dominance of Pseudomonas. It is noticeable that a major difference was observed at the end of shelf-life of MAP-stored fillets at 12 °C, where the dominant microbiota was constituted by the genus Serratia, while the relative abundance of Pseudomonas and Brochothrix was more limited. Furthermore, at the same temperature under aerobic storage of both whole and filleted fish, Pseudomonas almost co-existed with Acinetobacter, while the presence of both Erwinia and Serratia in whole fish was noteworthy. Overall, the present study provides useful information regarding the storage fate and spoilage status of whole and filleted European sea bass, suggesting that different handling and storage conditions influence the shelf-life of sea bass by favoring or delaying the dominance of Specific Spoilage Organisms (SSOs), affecting in parallel to some extent the formation of their consortium that is responsible for products’ sensorial deterioration. Such findings enrich the current knowledge and should be used as a benchmark to develop specific strategies aiming to delay spoilage and thus increase the products’ added value. © 2022 by the authors

An object-oriented reference model of the fuzzy front end of the new product introduction process

The global pressures of the modern market are placing an ever-increasing emphasis on the rapid development and introduction of new products. Central to this aim is the implementation of an effective business process for managing and controlling product innovation. Research has shown that the front end stages of the so-called new product introduction (NPI) process are weakest in a high proportion of companies and direct support is needed in this area. This paper describes how an object-oriented methodology has been applied to develop a reference model and architecture to facilitate the re-engineering and implementation of a high quality business process and help remove the fuzziness of the critical early stages of NPI. The results from the application and testing of this tool within a wide range of different companies are summarised and used to help derive conclusions regarding the validity of the research

The dynamics underlying service firm-customer relationships : insights from a study of English Premier League soccer fans

Researchers have argued that consumers frequently view marketing efforts as intrusive and that they fail to exhibit either trust or commitment. However, studies have found that some customers develop strong emotional relationships with firms, often independently of firm-driven relationship-building efforts. These confusing findings indicate that there is a need for additional research to explore the dynamics underlying service firm—customer relationships. The aim of this study is to elucidate customers' conception and manifestation of their relationships with service firms. Therefore, the objectives are to uncover the extent to which various types of customers exhibit relational links with service firms and to generate insights into the manner in which such identification is manifested. After a review of recent studies into relationship marketing, the authors present and explain the research design and method. Then, the authors present the findings that emerged during the focus groups and in-depth interviews with soccer supporters