Relative contribution of natural productivity and compound feed to tissue growth in blue shrimp (Litopenaeus stylirostris) reared in biofloc: Assessment by C and N stable isotope ratios and effect on key digestive enzymes

The aim of this study was to assess the relative contribution of natural productivity and compound food to the growth of the juvenile blue shrimp Litopenaeus stylirostris reared in a biofloc system. Two experiments were carried out based on the same protocol with three treatments: clear water with experimental diet (CW), biofloc with experimental diet (BF) and biofloc unfed (BU). Shrimp survival was significantly higher in biofloc rearing than in CW rearing. The contribution of the biofloc to shrimp diet was estimated through measurement of carbon and nitrogen stable isotope ratios in shrimp and food sources. Different isotopic compositions between feeds were obtained by feeding natural productivity with a mixture rich in fish meal and the shrimps with a pellet containing a high level of soy protein concentrate. Using a two source one-isotope mixing model, we found that the natural productivity of the biofloc system contributed to shrimp growth at a level of 39.8% and 36.9%, for C and N, respectively. The natural food consumed by the shrimps reared in the biofloc system resulted in higher gene expression (mRNA transcript abundance) and activities of two digestive enzymes in their digestive gland: α-amylase and trypsin. The growth of shrimp biomass reared in biofloc was, on average, 4.4 times that of those grown in clear water. Our results confirmed the best survival and promoted growth of shrimps using biofloc technology and highlighted the key role of the biofloc in the nutrition of rearing shrimps. Statement of relevance In this study, we have applied an original protocol to determine the respective contribution of natural productivity and artificial feeds on the alimentation of the juvenile blue shrimp L. stylirostris reared in biofloc system by using C and N natural stable isotope analysis. Moreover, we have compared, in shrimp digestive gland, the α-amylase and trypsin enzyme activities at biochemical and molecular levels for two different shrimp rearing systems, biofloc and clear water. In our knowledge, the use of molecular tool to study the influence of biofloc consumption on digest process of shrimp was never carried out. We think that our research is new and important to increase knowledge on biofloc topic.

The joint European Research Infrastructure Network for Coastal Observatories: Achievements and Strategy for the Future

This document is summarizing a major part of the work performed by the FP7-JERICO consortium, including 27 partner institutions, during 4 years (2011-2015). Its objective is to propose a strategy for the European coastal observation and monitoring. To do so we give an overview of the main achievements of the FP7-JERICO project. From this overview, gaps are analysed to draw some recommendations for the future. Overview, gaps and recommendation are addressed at both Hardware and Software levels of the JERICO Research Infrastructure. The main part of the document is built upon this analysis to outcome a general strategy for the future, giving priorities to be targeted and some possible funding mechanisms, but also upon discussions held in dedicated JERICO strategy workshops. This document was initiated in 2014 by the coordination team but considering the fact that an overview of the entire project and its achievement were needed to feed this strategy deliverable it couldn’t ended before the end of FP7-JERICO, April 2015. The preparation of the JERICO-NEXT proposal in summer 2014 to answer an H2020 call for proposals pushed the consortium ahead, fed deep thoughts about this strategy but the intention was to not propose a strategy only bounded by the JERICO-NEXT answer. Authors are conscious that writing JERICO-NEXT is even drawing a bias in the thoughts and they tried to be opened. Nevertheless, comments are always welcome to go farther ahead. Structure of the document The Chapter 3 introduces the need of sustained coastal observatories, from different point of view including a short description of the FP7-JERICO project. In Chapter 4, an analysis of the JERICO coastal observatory Hardware (platforms and sensors) in terms of Status at the end of JERICO, identified gaps and recommendations for further development is provided region by region. The main challenges that remain to be overcome is also summarized. Chapter 5 is dedicated the JERICO infrastructure Software (calibration, operation, quality assessment, data management) and the progress made through JERICO on harmonization of procedures and definition of best practices. Chapter 6 provides elements of a strategy towards sustainable and integrated coastal observations for Europe, drawing a roadmap for cost-effective scientific-based consolidation of the present infrastructure while maximizing the potential arising from JERICO in terms of innovation, wealth-creation, and business development. After reading the chapter 3, for who doesn’t know JERICO, any chapter can be read independently. More details are available in the JERICO final reports and its intermediate reports; all are available on the JERICO web site (www.jerico-FP7.eu) as well as any deliverable. Each chapter will list referring JERICO documents. A small bibliographic list is available at the end of this deliverable.