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Summary |
In the Netherlands, fish is produced in Recirculation Aquaculture Systems (RAS) which is considered to be one of the most sustainable types of fish production. However, most species reared in these systems exhibit growth retardation (GR) as compared with fish reared in flow-though systems. The mechanisms behind GR remain unknown, limiting the possibility to develop strategies at the farm level that limit/eliminate GR and therefore enhance the economic feasibility of RAS. Basic information regarding GR will be gathered during this project, such as the characterization of GR in the relevant fish species, the age and species-specificity and whether GIF originate from fish or/and bacteria in the biofilter. A decrease in growth rate may arise either as a consequence of a decreased feed intake and/or feed efficiency. In the case of GR linked to RAS it is still not known how important changes in feed intake/efficiency are. Furthermore, several behavioural, health (immune) and endocrine mechanisms are probably underlying the changes in feed intake/efficiency and ultimately in growth. These mechanisms have never been explored in the context of GR in RAS and will also be investigated in this project. |