Rainbow trout (Oncorhynchus Mykiss) from aquaculture – meat quality and importance in the diet

Abstract

Rainbow trout (Onchorhynchys mykiss) is one of the most popular fish species in nature, but in many countries it is also recognized and accepted as cultivated/farmed fish species, due to its fast growth and excellent nutritional quality. In the farming technology for rainbow trout, the following elementary conditions must be fulfilled: clear water with sufficient oxygen content (10 mg/l), adequate temperature (8–12 ºC) and flow of water, systematic nutrition using different types of industrial or natural food, etc. In Serbia, most of the produced marketable size rainbow trout is marketed as fresh, cooled (90%), and, in less extent, as scaled and gutted and packaged. Of all fresh water salmonid species, rainbow trout is mainly farmed for consumption. In addition to the fact that the farming of this fish species is very attractive for a large number of producers, considering the potential for high yields per unit of water volume, it is also characterized by high tolerance to temperature fluctuations and aggravation of the water quality, as
well as fast growth rate. The nutritive value of fish meat is determined by the amount of protein, fat, minerals and vitamins contained and it depends on the fish species and age, farming method, composition of food and season of the year. Rainbow trout farmed in our country contains approx. 18% proteins, 3.3% of fat, 76.3% of water, 1.3% of ash and 48.5 mg/100g of cholesterol. Its energy value is approx. 440 kJ/100g. The amounts of n–3 and n–6 fatty acids in lipids of marketable size rainbow trout from aquaculture in Serbia give a very favourable n-3/n-6 ratio of approx. 1.60. P/S index for studied fish species is 1.54, and ratio between unsaturated (UFA) and saturated fatty acids (SFA) is 3.51.
Key words: Rainbow trout, proximate chemical composition, cholesterol, fatty acid composition.