ANN 111: Principles of Animal Nutrition and Feed Technology (2+1)

DIGESTIBILITY COEFFICIENT

• Before the ingested food becomes available, it must undergo digestion during which it is broken down to simpler substances, which are absorbed in the body.
• Proteins differ in their digestibility.
• The term digestibility Coefficient of protein refers to the percentage of the ingested protein absorbed into the blood stream after the process of digestion is complete.
• The digestible protein in a food may be determined by digestibility trials.
• For determination of digestibility coefficient the following data are required.
  • Food nitrogen in take.
  • Total faecal nitrogen excreted and metaboic faecal nitrogen (when an animal is fed on nitrogen - free diet certain amount of nitrogen is excreted in the faeces. This is derived mainly from the digestive juices. This is called metabolic faecal nitrogen).
• Digestible protein figures are not entirely satisfactory assessments of a protein, because the efficiency with which the absorbed protein is used differs considerably from one source to another.
• In order to take this into account, methods of evaluating proteins have been derived which are based on the response of experimental animals to the protein under consideration.