MEASUREMENT OF ENDOGENOUS AMINO-ACID LOSSES IN POULTRY

1. Ileal endogenous amino acid losses were determined in broiler chick ens and in cannulated cross-bred layer strain cockerels using either a nitrogen-free diet, regression analysis or a 48 h fast. 2. Endogenous amino acid flows to the ileum in fasted cockerels were significantly lower than those obtained both by feeding the nitrogen-free diet, and from regression analysis in either broilers or cockerels. Regression a nalysis gave the highest flows. 3. The apparent digestibility coeffici ents of amino acids in a diet containing 200 g/kg crude protein were l ower in broilers (0.84) than in cockerels (0.88). When corrected, by r egression analysis, for the contribution of endogenous amino acids, th e true digestibility coefficients became 0.90 and 0.92 respectively.