Organic production of gilthead sea bream (Sparus aurata) using organic certified green pea protein and seaweed. Effects on growth, feed conversion and final product quality.

Abstract

The aim of this study was to evaluate the use of novel ingredients such as green pea protein and Ascophyllum nodosum, a brown seaweed for the replacement of fish meal in feeds suitable for organic production. The growth, feed utilization and fillet composition of gilthead seabream were examined under a lab scale trial and based on the results a large-scale field trial was conducted in the facilities of Galaxidi marine farms in order to compare a novel feed with a typical commercial feed suitable for organic production.Final weight, growth rate and somatic indices of the fish fed these alternative ingredients did not show significant differences compared to the control group fed the commercial diet. Muscle protein content was higher in the fish fed the higher inclusion level of green pea protein, whereas lipid content was lower in both experimental diets. Fatty acid composition, in terms of n-3 and n-6 polyusaturated (PUFA), eicosapentanoic (EPA) and docosahexaenoic (DHA) acid content was higher in the muscle of the fish fed the experimental diets. In the case of the liver, the fatty acid profile reflected the feed composition, and the fish fed the diet with an inclusion of 19% green pea protein showed a lower content of protein and a higher content of n-6 PUFA, and monounsaturated fatty acids (MUFA).In view of the results obtained, the ingredients assayed in this study could be used in organic feed formulations as alternatives to fish meal obtained from trimmings since no negative effects were detected neither on fish growth, muscle composition, fish health nor end product quality and nutritional value.