Percentage of fat retained in bran for poultry feed

De oiled rice bran containing less than 1 %;fat is being used extensively in poultry feed However broiler feed plants are using additional fat by way of adding some volume of vegetable oil into the feeds in order to provide the desirable percentage of required fat. In the event residual fat in rice bran can be allowed to remain in the bran to the extent required then what would be the ideal percentage of fat that can be retained in the bran such that feed plants make use of this quality of rice bran?