Investigations on energy metabolism of juvenile turbot

• Main Author: Dietz, Carsten
• Other Authors: Susenbeth, Andreas, Schulz, Carsten, Krieter, Joachim
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2012
• Subjects: thesis; ddc:570; energy metabolism; maintenance requirement; efficiency of energy utilization; turbot; Energiestoffwechsel; Erhaltungsbedarf; Effizienz der Energieverwertung; Steinbutt; Iceland; Turbot
• Online Access: https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-92772; https://macau.uni-kiel.de/receive/diss_mods_00009277; https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00004438/PhD_thesis_Carsten_Dietz_2012.pdf

Aquaculture continues to be the fastest-growing branch producing foods from animal origin. In Europe the production of turbot (Psetta maxima), a species of high commercial value, rapidly developed over the last decade and is highest among flatfishes. Considering an expected increase in turbot production accompanied with decreasing market prices it is of highest relevance to improve the production efficiency of turbot farming to maintain an adequate profit margin. Feeding efficiency is a crucial factor, because feeds represent a minimum of 17% of the total production costs. In addition to the energy required for maintenance the feed must supply the precursors for new tissue production as well as the energy necessary for synthesis of both protein and lipid. Informations about the maintenance energy requirement and the efficiency of energy utilization for growth are the basis for a performance-related feeding and a corresponding diet formulation. In the present study the digestible and metabolizable energy requirements for maintenance (DEm; MEm) as well as the respective efficiencies of energy utilization for growth (kg (DE); kg (ME)) in juvenile turbot were determined and the effects of biotic or abiotic factors examined. Two different methods for determination were applied. In chapter 1 growth experiments accompanied with comparative whole body composition analyses were realized to determine DEm and MEm as well as kg (DE) and kg (ME). The effects of the fish strain (Denmark, DK; Iceland, IS) as well as the partially replacement of fish meal by wheat gluten in the diet were examined as possible factors affecting the energy metabolism. Turbot were reared in a recirculation aquaculture system for 67 days. MEm and DEm were 15.5-21.4 and 17.0-23.5 kJ kg-0.8 d-1, respectively, and kg (ME) and kg (DE) were 0.63-0.68 and 0.59-0.64, respectively. MEm and DEm as well as for kg (ME) and kg (DE) in turbot from IS were higher than in fish from DK, but without any effect on energy retention. Turbot receiving the diet where ...