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

Protein replacement value

PROTEIN REPLACEMENT VALUE (PRV)

• This value measures the extent to which a test protein will give the same balance as an equal amount of a standard protein.
• Two nitrogen balance determinations are carried out, one for a standard such as egg or milk protein, which is of high quality, and one for the protein under investigation.
• The PRV is calculated as follows:

                            PRV = (A – B) / N intake

• Where A = N balance for standard protein in mg/basal kJ, B = N balance for protein under investigattion in mg/basal kJ.
• The method can also be used to compare two proteins under similar conditions, when no standard value for replacement is required.
• The PRV measures the efficiency of utilisation of the protein given to the animal.
• Other methods measure the utilisation of digested and absorbed protein.