Reducing the CP content in the AA-supplemented
diets reduced total N intake and thus, decreased N excretion
on a grams per day basis. The total N excretion
after feeding the low-CP diet supplemented with Ile
and Val for wk 1 was reduced by 26% compared with
the high-CP diet, and after wk 4 this difference was
29% reduced. When only Val was added to the diet, the
wk 4 total N excretion was 35% less than the positive
control. These data show that with the aid of crystalline
AA, a 10% reduction in total N excretion is possible
for every 1% reduction in CP content of the diet. Very
similar decrease has been shown by other investigators
who have measured reductions in total N excretion
of low-CP diets with crystalline AA