THE EFFECT OF THE ESSENTIAL TO NONESSENTIAL AMINO ACID RATIO ON TURKEY PERFORMANCE AND CARCASS COMPOSITION

Abstract

The effect of altering the proportion of dietary protein supplied as essential amino acids (EAA) on the performance and carcass characteristics of young turkeys (to 3 wk of age) was investigated at three dietary protein levels (22, 26 and 30%) using semipurified diets. Four ratios of EAA to nonessential amino acids (NEAA) were employed (70:30, 60:40, 50:50 and 40:60) at each dietary protein level. Maxima in weight gain, percent and total carcass protein and feed intake were observed when EAA supplied 60% of total protein (i.e., the 60:40 ratio) at each protein level. The differences in weight gain and total carcass protein were largely attributed to differences in feed intake, since feed conversion efficiency was relatively unaffected by altering the EAA: NEAA ratio. More specifically, weight gain was shown to be limited by total protein intake. Since weight gain was maximized at the 60:40 ratio diets (in which all EAA are supplied at 128% of requirement) at least one of the EAA requirement values is incorrect. Key words: Turkeys, essential amino acids, protein requirement