Effects of Degree and Duration of Heating on the Digestibility of Powdered Fish Meal

The muscles of Carp and Cod were minced and deprived of as much connective tissue as possible. The muscle pastes thus obtained were dried on glass plates at various temperatures for varying lapses of time. And they were transferred to desiccator and left at room temperature to ensure complete drying. The thin films thus obtained were taken out and powdered, fats being removed with ether. The preparations were digested with pepsin in 0.01 N HCI solution and the digestibility was determined by the following formula: Digestibility=S/N×100, S……increased soluble nitrogen, N……total nitrogen to be digested. As shown in the accompanying figures, the digestibility of the powdered fish muscles diminishes with increasing degree and duration of heating. The difference of digestibility of various fish meals appears to be due to degree and duration of heating in the manufacturing procedures.