Fillet texture of rainbow trout as affected by feeding strategy, slaughtering procedure and storage post mortem

Due to the enactment of environmental legislation in Denmark, feed expenditure by commercial aquaculture operations has been limited. This development has created a demand for high energy diets, which presently dominate the market place. Such diets limit waste load to the surrounding environment, but is the quality of the fish as end product affected?

It is well established that fillet quality varies according to several factors, including feed composition and feeding regime. An experiment was thus designed to evaluate the effect of differing: i) amount of protein fed, ii) amount of fat fed, iii) starvation period before harvesting, iv) method of slaughter and v) storage time post mortem on fillet quality of 600g trout. The fillet fat content was examined and related to each of the five factors investigated in order to determine which had the most pronounced effect on fillet texture post mortem.

Texture measurements were undertaken using an Instron Universal Testing Machine and sensory analysis. Results indicated that fillet fat content could be increased 20% without affecting texture. Storage time post mortem was found to be the single most important factor affecting fillet texture. Sensory analyses verified the results obtained by instrumental texture testing.