Metabolic network model of the central metabolism of avian CR.pIX cells. Main parts are glycolysis (purple), amino acid catabolism and the TCA cycle (green) which takes place in the mitochondria (grey). Reaction reversibility indicated by arrow heads. All fluxes are given in [μmol/gDW/h]. A: shows calculated flux ranges from scenario 1 (by FVA) in square brackets, B: shows determined rate values from scenario 2 (by MFA). The values are also given in Additional file 1: Table S2.