Effect of combined fishmeal and fish oil replacement on growth performance, flesh quality and shelf life of European sea bass (Dicentrarchus labrax)

Abstract

The present study was aimed to evaluate the effect on growth performance, muscle integrity and quality traits throughout ice storage of distinct levels of substitution of fish meal (FM) and fish oil (FO) by sustainable plant raw materials (plant meal and oils) on European sea bass (Dicentrarchus labrax) in long-term feeding of 18 months. Six experimental diets, isonitrogenous (45% crude protein) and isolipidic (21%), containing gradually reduced levels of FM and FO as follows (%FM/%FO): 20/6, 20/3, 10/6, 10/3, 5/6 and 5/3 were evaluated. The reduction of FM resulted in a significant decrease (17–20%) of fish growth performance. There were no differences among the experimental diets for myofibrillar or endoproteases antibodies (anti-desmin, anti-dystrophin, anti-calpastatin, anti-M-calpain, anti-Micro-calpain) after 8 days of storage period. FO substitution increased n-6 fatty acids (FA) and reduced saturated FA, n-3 LC-PUFA (Long-chain polyunsaturated fatty acid) and n-3/n-6 ratio. Monounsaturated fatty acids were not affected by the content of the diet. No organoleptic changes were observed following the Quality Index Method (QIM) scheme, but a higher hardness measured by instrumental texture in whole fish and the raw fillet was associated with diets with high inclusion of FM at the beginning of storage, not perceptible in the cooked fillet.