EFFECT OF GROWTH-RATE ON FLESH CHARACTERISTICS OF BROWN TROUT (SALMO-TRUTTA) REARED IN SEA-WATER

Flesh quality was assessed in brown trout (Salmo trutta) reared in sea water during 18 months and with a body weight range between 1.4 to 4.6 kg. Various criteria were used : morphometrics characteristics, chemical composition (water, lipids, proteins and ash), physical properties (hydration, mechanical resistance, colour), biochemical (myofibrillar protein) and histological characteristics (adipocytes, muscle fibers) and sensory parameters. Characteristics of the flesh were only slightly affected by differences in growth rate. An increase in the lipid content and in the intensity of colour with increasing growth rate was observed. The water holding capacity of the flesh was also affected by differences in growth rate, but without any related effects on sensory assessment of juiciness. Fish with intermediate growth rate demonstrated specific differences in characteristics of the flesh when compared to fish with low and high growth rates. It concerned especially the disappearence of a myofibrillar protein (of high molecular weight) and the increase in salmonid specific odour and flavour.