Controlled comparative feeding experiments for finfish

Understanding the impact of different dietary composition on the growth, health and welfare of farmed fish is essential to allow optimal diets to be developed in aquaculture. This is particularly important in the case of diets developed to be ecologically improved through the use of sustainable land-sourced protein sources. The reaction of aquatic fish to diet formulations can only be determined under controlled feeding conditions, where a wide range of key indicators are collected to provide a holistic view of the animals’ response in terms of growth, immune status and potential physiological stress.

Diet formulation will be defined in a separate SOP.

Firstly, fish must be acclimatised to the tanks and RAS System to be used for experiments. The system must be equipped with an appropriate number of replicate units to allow a minimum of 4 replicates per diet / treatment. All appropriate veterinary allowance/ethics procedures must be complied with.

In these experiments, one aims to:

1)      Randomly assign a number of formulated diets to equal numbers of appropriately similar animals in replicate tanks and to feed these diets to these animals over a suitable period of time to allow observation of the effects (as measured by a variety of response parameters) of the different diet treatments isolated from all other potential effects.

2)      The effectiveness of the experiment lies in the exact application of the diets, and extremely accurate sampling and measurement at the experimental onset, at interim measurements and at final sampling.

3)      Selected parameters to be monitored can be grouped either;

·         by sampling type i.e. biometrics (size, organ indices etc.), blood/serum analytics (haematocrit, glucose, pH etc.), histology (liver histology) and behavioural observation; or

·         by indicator type i.e. immune and metabolism (lysozyme in liver / gills), stress (behavioural observation), performance (growth, food conversion ratio).