Fatty acids of tissues of rainbow trout Parasalmo mykiss (Walbaum, 1792) depending on season, age, and forage composition

Abstract

Modification of the biochemical composition of tissues in fish is in many respects determined by the environmental impact. In nature, unlike aquarium experiments, it is necessary to consider the integrated pattern of different impacts on the body; therefore, it is rather difficult to distinguish the factor exerting the key impact on metabolism. The use of ecological– biochemical indicators of the state of fish allows us not only to identify the dominant environmental factor, but also to assess the extent of its impact [1]. Fatty acids play an important role in the adaptive mecha� nisms of fish and, due to a high plasticity of their com� position, are among the most efficient criteria of the assessment of the body state [2]. We performed an analysis of the effects of some fac� tors on the fatty acid composition of the muscles and liver of females of the cultivated form of rainbow trout Parasalmo mykiss (Walbaum, 1792) aged 1+ and 2+ reared in a trout farm on Lake Onega. The regimen of feeding was exercised in accordance with standards recommended for cultivation of salmonids and did not depend on the brand of the combined forage. The percentage ratio of fatty acids of total lipids (FA) was determined. The indices were assessed using common methods of lipid analysis [3–5]. Statistical data processing was performed using MANOVA with the following controlled factors: season, forage, and age. In the course of the studies, a qualitative corre� spondence and quantitative variability of the fatty acid composition of all the studied samples of tissues of fish and combined foods were established. A significant impact of the trophic factor on the percentage of monoenoic fatty acids in the muscles of trout was found (Table 2). In previous studies [6, 7, etc.], it was shown that precisely this group of acids is involved in triacylglycerins that are deposited in the muscles of the trout.