Effects of increased astaxanthin in the feed on rainbow trout quality

Summary

The overall idea of this project was to increase the value of the production when farming rainbow trout (Oncorhynchus mykiss) in Norway through the combined production of fish for food as well as consumer eggs. From previous studies with rainbow trout from Svanøy AS we have seen a marked decrease in muscle color (astaxanthin content) with rainbow trout in the period right before the eggs are suitable for consumption. This contributes to quality deterioration of muscle; the paler fillet being classed as lower quality. Trout cannot make astaxanthin themselves and depend on supply through the feed. To improve the pigmentation of the muscle; a trial was conducted to compare normal and increased levels of astaxanthin in the feed. The fish used in the project was bought as an "All female"group from AquaGen. Unfortunately, it turned out to be a mistake by the delivery, so that the fish was normally distributed male and female rainbow trout. This was not discovered until slaughter in the fall of 2018. The results showed that high levels of astaxanthin does not affect the muscle biochemical composition, roe color and muscle color as compared to the control group.