Comparative estimations of the energy content of fish tissue from bomb calorimetry, wet oxidation and proximate analysis

SUMMARY. Four methods were used to determine the energy content of somatic tissues of Perca fluviatilis. Two forms of direct calorimetry (both adiabatic and non‐adiabatic) and wet (dichromate) oxidation gave similar results. When energy contents were calculated from proximate analysis using accepted conversion factors (9.45 cal mg−1 for lipid, 5.65 cal mg−1 for protein) results were higher than those from the other methods. The discrepancy was eliminated when a lower, directly determined energy content for the extracted lipid fraction was used. Some historic and technical aspects of the comparison are discussed.