INFLUENCE OF FEED COMPOSITION AND FEEDING STRATEGY ON ORGANIC BROWN TROUT (Salmo trutta fario L.) PRODUCTION AND FINAL PRODUCT QUALITY

M. MANTHEY-KARL¹*, B. FRENZL², H. KARL³, R. REITER^4
1Max Rubner - Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Milk and Fish Products, Palmaille 9, 22767 Hamburg, Germany.
²Institute for Fisheries, Bavarian State Research Center for Agriculture, Starnberg, Germany
³Max Rubner - Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Milk and Fish Products, Palmaille 9, 22767 Hamburg, Germany.
⁴Institute for Fisheries, Bavarian State Research Center for Agriculture, Starnberg, Germany
* Corresponding Author : monika.manthey@mri.bund.de

Received : 15-04-2015     Accepted : 28-05-2015     Published : 18-06-2015
Volume : 6     Issue : 1       Pages : 183 - 190
J Fish Aquaculture 6.1 (2015):183-190

Keywords : Salmo trutta fario, flesh quality, feed trial, organic production, body composition, quality assessment
Academic Editor : Kale Mu
Conflict of Interest : None declared
Acknowledgements/Funding : The project was financed by the German Federal Ministry of Food and Agriculture (BMEL) and supervised by the German Federal Office for Agriculture and Food (BLE). The results have been published in a final project report [44, in German language]. The auth

Brown trout (Salmo trutta fario L.) were raised according to organic guidelines of the German association “Naturland”. Three certified organic trout feeds were tested. A control group was fed a commercial diet. Organically grown fish were larger at harvest than control fish and in better condition. The feed conversion ratio was higher for the control diet. Specimens were analysed comparing body composition including maturation, gross energy level, carcass and fillet yield. Lipid levels of 5.5% to 6.9% were found in the fillets, associated with a sum of eicosapentaenoic acid and docosahexaenoic acid between 1.3% and 1.7%. Free amino acids varied only slightly (3.6 - 4.7 g kg-1 fillet). Mean values for taurine and selenium were between 0.5 mg kg-1 and 1.4 mg kg-1 and 0.10 mg kg-1 to 0.19 mg kg‑1, respectively; lowest contents were found in Brown trout raised with conventional feed. Water-binding ability and texture showed no systematic differences. Sensory evaluation rated all fillets as highly acceptable. This study demonstrates that organic feedstuffs for Brown trout production do not decrease final product quality.