Evaluation of different commercial processing methods on the nutritional value of poulty byproduct meal.

Poultry byproduct meal consisting of 5 volumes of feathers, 2 volumes of offal and 1 volume of blood, was processed in three different ways and evaluated for true metabolizable energy (TME), nitrogen retention in roosters and amino acid availability determined with a dye-binding method. The three processing methods were briefly as follows: Method A: The feathers, offal and blood were processed simultaneously. The total cooking   time was 5 hours and 45 minutes with a maximum temperature of 125 °C and a pressure of 150 kN/m².• Method B: The feathers were processed separately from the offal and blood for 55 minutes, reaching a maximum temperature of 135 °Cwith a pressure of 200 kN/m².• The blood and offal were added then and cooked for 20 minutes, reaching a maximum temperature of 110 °C and a pressure of 50 kN/m².• After the cooking process it was dried with hot air (100 °C) for 1 hour 30 minutes. Method C: The processing was the same as in method 8 except that the hot air drying time was increased to 3 hours. Significant (P ≤0,05) differences were found between the TME-values of method A and B. The TME-values were 19,20, 20,66 and 19,64 kJ/g (dry basis) respectively. The TME_n, N-retention and dye-binding values did not differ significantly between the three methods. From the TME and nitrogen retention values, it appeared that the poultry-byproduct meal where the feathers were processed separately from the blood and offal, was of a better quality than the poultry-byproduct meal where the feathers, blood and offal were processed simultaneously.