A Method for Determining the Gross Value of Protein Concentrates

INTRODUCTION IT IS well known that wide differences in the quality of protein concentrates may occur. This information has been accumulated by feeding protein concentrates in simplified diets, using rats as the experimental animals. The methods developed for the evaluation of protein concentrates with rats which used purified diets are of little practical value to the poultry industry because the proteins of the commercial poultry ration are usually composed of more than 50 percent cereal proteins. The growth obtained by the feeding of proteins to chicks is a result of a combination of response from the cereal proteins supplemented with protein concentrates from either animal or vegetable sources. Numerous experiments have reported the nutritive values of protein supplements in poultry rations. The methods used in these studies vary greatly, and no standard method of evaluating proteins has yet been adopted by workers in poultry nutrition. Record, Bethke, and Wilder (1934) . . .