Effect of Broiler Row Feather Processing on Chemical composition and Protein Fractions Based on The Cornell Net Carbohydrate and Protein System

Background and objectives: The demand for high-quality protein sources is likely to increase in the coming years, especially due to the increasing world population, which is estimated to reach about 9 billion by 2050, which may lead to more competition between humans and livestock for consuming high-quality protein sources, Therefore, it is important to identify and find alternative sources of protein for sustainable animal nutrition. Considering that millions of tons of feathers are produced worldwide every year, this by-product is considered a potential alternative to more expensive feed ingredients. Many biophysicochemical processes are used to increase the quality of feed sources, especially protein sources. Steam hydrolysis is a process commonly used to convert indigestible raw keratin into highly digestible feather meal. Since the protein digestibility of the feather in the living organism's digestive tract is relatively low, this method is not satisfactory. Therefore, according to the mentioned cases, the aim of the present study was to determine the effect of poultry feather processing on the chemical composition, total volatile nitrogen and protein fractions of feather meal based on the Cornell Net Carbohydrate and Protein System.
Materials and methods: This research was carried out in a 2x2x2 factorial method based on a completely randomized design with 8 treatments and 5 replications including: 1) raw feathers autoclaved at 120°C and 2 kPa pressure for 20 minutes; 2) raw feathers autoclaved at 120°C and 2 kPa pressure for 20 minutes, 0.25% sodium metabisulfite; 3) raw feathers autoclaved at 120°C and 2 kPa pressure, 0.15% protease enzyme; 4) raw feathers autoclaved 120°C and 2 kPa pressure for 20 minutes, 0.25% sodium metabisulfite, 0.15% of protease enzyme; 5) raw feathers autoclaved at 100°C and 2 kPa pressure for 20 minutes; 6) raw feathers autoclaved at 100°C and 2 kPa pressure for 20 minutes, 0.25% sodium metabisulfite; 7) Raw feathers autoclaved at 100°C and 2 kPa pressure, 0.15% protease enzyme; 8) Raw feathers autoclaved at 100°C and 2 kPa pressure for 20 minutes, 0.25% sodium metabisulfite, 0.15% of protease enzyme. Chemical composition and total volatile nitrogen were determined. The protein fractions (A, B1, B2, B3, C) of the processed feather meal were measured according to the Cornell University method.
Results: Dry and organic matter, crude protein, crude fat and ash were not affected by experimental treatments. The amount of total volatile nitrogen was affected by the experimental treatments. The processing of raw feather with protease enzyme significantly increased the amount of total volatile nitrogen (P=0.0015). The protein fractions of the processed raw feather were affected by the treatments. There was a statistically significant difference between fraction B1, B3 and C. The addition of sodium metabisulfite during raw feather processing had a significant effect on fraction B1 (P < 0.0001) and B3 (P < 0.0001). The use of protease enzyme during the processing of raw feathers had a significant effect on fraction B1 (P<0.0001). The effect of different temperatures in raw feather processing was significant on fraction C (P<0.0001).
conclusion: According to the results of this research, it can be seen that the use of sodium metabisulfite in the processing of raw feathers causes an increase in the B1 fraction and a decrease in the B3 fraction, and also the addition of protease enzyme in the raw feather processing causes an increase in the amount of total volatile nitrogen and B1 fraction. Also, the results showed that processing at a lower temperature (100 °C) reduces the C fraction.