Effect of different dietary fat content and fat type on the growth and body composition of intensively reared pikeperch Sander lucioperca (L.)

Abstract

Two, 42-day feeding experiments were carried out in aquaria working in a recirculation system, to determine the influence of the different dietary fat levels and fat sources on the growth and body composition of pikeperch fingerlings. In the first experiment three levels of dietary fat (F0: 60; F1: 120; F2: 180 g kg[superscript [-]1]) were tested, compared with a commercial diet (Trouvit, 240 g kg[superscript [-]1] fat content). F1 and F2 were formulated by adding fish oil. Best growing and feed conversion ratio was obtained with the commercial control diet, which produced also the highest total body fat (117 g kg[superscript [-]1]) while respective values of fish fed on the other three diets varied between 74.1 and 85.1 g kg[superscript [-]1]. Different feeds had no significant differences in crude protein content of the fish body. In the second test, besides feeds F0, F1 and F2, two additional feeds were formulated containing 127 g kg[superscript [-]1] (L1) and 178 g kg[superscript [-]1] (L2) crude fat (from linseed oil). Dietary fat levels and fat sources had significant effect neither on growth nor on feed conversion ratio. Chemical composition of the whole body did not change significantly due to the different feeds. Linseed oil had a decreasing effect on the sum of saturated fatty acids and increased the oleic and the [alpha]-linoleic acid proportions in fillet. However, total polyunsaturated fatty acid (PUFA) proportion remained constant.