Self-selection of diets with different oil oxidation levels in gilthead seabream (Sparus aurata)

Abstract

3 páginas, 1 figura, 1 tabla.The present research looked at the ability of gilthead seabream to discriminate between two similar diets differing only in the extent of lipid oxidation. Six groups of 4 fish (254 g initial wet weight) were allowed to be selected by means of self-feeders between two complete diets (34.5% casein + gelatin, 14.8% fish oil + soybean oil, 24.8% dextrin and 25.9% vitamins, minerals, filler and binder) which differed only in the oxidation level of the lipid source: 6.2 meq/kg for the control (D1) and 100.0 meq/kg for the oxidized diet (D2). During the first nine days of the trial, fish took similar amounts of D1 and D2, although there was a clear tendency to gradually avoid D2. Finally, on day 10 fish demanded a significantly higher percentage (82%) of D1. When the diets were interchanged to investigate feeder preferences, two selection patterns were observed: three groups resumed their selection for D1 from day 7 onwards, while the other three groups did not show a clear preference for any diet until they were subjected to a 3-week fasting period (which boosts internal oxidation), after which they significantly selected D1. Taking together the results before and after fasting, gilthead seabream were able to discriminate and avoid a diet with oxidized lipids, and the physiological state of fish (oxidative stress caused by fasting) appeared to reinforce their selection/avoidance behavior.The present research was funded by the project AQUAGENOMICS 28502 (Consolider-Ingenio Program) granted to F. J. Sánchez-Vázquez and M. Yúfera and the projects from the Spanish Ministry of Science and Innovation (MICINN) (project AGL2010-22139-C03-01) and Fundación Séneca (project 08743/PI/08).Peer reviewe