Acronym TOWTAU
Category
Aquaculture
Title Towards fishmeal-independent fish diets: the role of taurine Programme Nat. Programme (supported by ESIF)
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National-European Coordinator Cláudia Raquel Cêa de Aragão Teixeira Coordinator email caragao@ualg.pt
Coordinator institution
CCMAR - Centre for Marine Sciences (Portugal)
Institutions involved
IPIMAR - Portuguese Institute for Fisheries and Sea Research (Portugal) ,
UiB - University of Bergen (Norway) ,
Start year 2012 End year 2015 Funding (€) € 176,453 Website NA Summary In recent years, the reality of the rising cost of fishmeal as well as the increasing voice of environmentally aware consumers have exerted pressure on the aquaculture industry to find alternative protein sources in the production of fish feed. Consequently, there has been an increasing focus on terrestrial plantmeals as a readily available protein replacement. However, when large amounts of dietary fishmeal are replaced by plantmeal, lower fish growth, poorer physiological condition or reduced feed efficiency is usually observed. Among other factors, these negative effects may result from a taurine deficiency, which is virtually absent in plants but is particularly abundant in fish. Although considered an amino acid, taurine lacks a carboxyl group and cannot be incorporated into protein or oxidised as an energy substrate. However, taurine participates in several physiological functions, such as bile salt synthesis, membrane stabilization, modulation of neurotransmitters, antioxidation and detoxification. Senegalese sole (Solea senegalensis) has long been recognized as a promising flatfish species for Mediterranean marine fish farming, due its high price and market demand. Large scale commercial farming of sole is gaining "momentum" in Portugal and Spain, due to major research advances and the fact that producers are searching to alternative species to turbot. However, growth heterogeneity still plagues the industry. Members of the TOWTAU project have previously shown that sole has a high dietary protein requirement, but tolerate high levels of fishmeal replacement by plant protein sources. Since commercially available diets for sole still rely largely on fishmeal, the development of a plant-protein based diet seems pivotal to ensure its successful, competitive and sustainable commercial culture. Taurine seems to be an essential dietary nutrient for marine fish species and recent studies reported positive effects of dietary taurine supplementation on growth and physiological condition. Therefore, the proposed TOWTAU project intends to: (1) Investigate how taurine supplementation to plant-protein based diets affects amino acid and lipid absorption/metabolism; (2) Understand how dietary lipid modulate taurine availability and recycling in fish; (3) Define an optimum level of taurine inclusion in sole diets with high levels of fishmeal replacement, in order to promote improved and less heterogeneous growth and an optimal physiological condition; (4) Implement the use of a plant-protein based diet in Senegalese sole culture. Contrary to other studies, the TOWTAU project will use a plant-protein based diet formulated using a mixture of different plant-protein sources to replace up to 75% of the proteins from marine origin. The first Task will test different forms of taurine inclusion in the diet. This is to reduce leaching of this nutrient to the environment and to ensure an efficient and dependable delivery of dietary taurine to the fish. This is particularly important as Senegalese sole exhibit passive feeding behaviour. After determining the most suitable technology for taurine supplementation to the plant-protein based diet, dietary taurine will be evaluated in terms of its impact on protein-sparing. This means that the TOWTAU project will use an integrated approach looking at both amino acid and lipid metabolism. This will be carried out by integrating novel methodologies (developed by the group) in fish nutrition, such as the controlled tube-feeding of radiolabelled nutrients and molecular approaches, with classic feeding trials. The later will analyse zootechnical parameters, as growth and feeding efficiency, but will also rely on other tools (e.g. histochemical, enzymatic, biochemical analyses) to understand changes in cellular morphology, enterohepatic recycling pathway or protein and lipid retention, as a result of changes in metabolism and nutrient uptake. The TOWTAU project will generate knowledge and new insights on taurine metabolism and its impact on the physiology of fish growth, and on its dietary requirement for sole. This will contribute greatly to the development of a sustainable Senegalese sole culture, with the potential to improve the farming of other species such as turbot. Moreover, it is hoped that this knowledge will give a competitive edge to Portuguese and European aquaculture.
The TOWTAU project aims to understand: (1) How taurine supplementation to plant-protein based diets affects amino acid absorption and/or metabolism; (2) How dietary taurine supplementation affects lipid absorption and metabolism; (3) How dietary lipid modulates taurine availability and recycling in fish. Ultimately, it is intended to; (4) Define an optimum level of taurine inclusion in diets with high levels of fishmeal replacement, to improve fish growth and ensure an optimal physiological condition; (5) Implement the use of a plant-protein based diet in Senegalese sole culture.
Keywords
Flatfish;
Protein;
Fish meal replacement;
Fish;
Sole;
Diets;
Marine Region
38
Portuguese Waters (27.IXa,27.IXb)
1
Marine Region Map
