Choice Feeding as a Means of Identifying Nutritional Needs With Two Methods of Amino Acid Formulation

Abstract

Male broilers from 11 to 49 days of age were assigned to one of four feeding treatments: Single diets (control), a choice of starter and finisher diets, a choice of high energy and high protein diets in relation to amino acid: lysine ratio and a choice of high energy and high protein diets in relation to amino acid: protein ratio. Birds fed both energy-protein treatments had worse body weight, feed conversion and carcass characteristics than did birds fed single diets or starter and finisher diets. The high energy-protein diets formulated in relation to lysine had the poorest carcass characteristics for all parameters except for wing and leg quarter yields. Birds given the choice feeding systems selected more high energy diet than high protein diet especially during the period of 11 to 22 days of age. Choice-fed broilers of both energy-protein treatments consumed less protein (total intake or percentage of consumed feed) for all periods, whereas these birds consumed similar energy intake at all age periods except for 42 to 49 days of age and higher energy density than did birds fed the other two feeding systems. As the choice-fed birds grew older, the selected energy content tended to wane while the selected protein contents tended to increase. These data indicate that the high protein diet formulated with amino acids in relation to lysine did not overcome the failure of choice feeding with high energy and high protein diets to sustain productivity since energy may be the driving force for feed selection.