Amino Acid Digestibility Methods

The use of digestible amino acids (AA) for the formulation of poultry diets has been recognized as being preferable to formulating diets on a total AA basis. Thus, determination of AA digestibility of feed ingredients has become crucial. UGA poultry scientists conducted two experiments to compare the AA digestibility coefficients obtained by the standardized chick ileal digestibility and the precision-fed cecectomized rooster assays. The six test diets contained corn, wheat, soybean meal, poultry by-product meal, feather meal and fish meal as the sole source of protein. They found that for some feed ingredients, AA digestibility coefficients obtained by the rooster assay might not be applicable to young chicks. So the incorporation of different AA digestibility values in diet formulation for young chickens might become necessary. The use of AA digestibility values from either method would have dramatic effect on diet formulation and cost, so it is crucial that the scientists determine the best method.