RIESULTS AND DISCUSSION
Supplr:menting the 2OVo protein basal diet
with lysine or nonessential nitrogen (glycine)
lailed to alter weight gain to 4 wk of
age (T'able 2). The addition of both methionine
and lysine (treatments 3 and 5) resulted
in a significant improvement in
weight and feed:gain ratios which equalled
those of treatments 6 and I that contatned
247o protein Although there was no improvement
in weight gain for birds fed the
nitrogen-supplemented basal diet (treatment
4), an improvement in feed:gain ratio
was noted. This was accomplished by a reduction
in energy intake to approximately
21 MJ/kg of gain, as compared to close to
24 MJlkg of gain for the 20Vo proteinbasal
and the lysine-supplemented group (treatments
1 and 2, Table 2), and was similar to
the energy intake for the methioninesupplemente
d2OVo protein diet andthe 24Vo
protein diets. This type of response, to nonessential
nitrogen, is similar to that reported
by Guillaume and Summers (1970)
with diets containing protein in excess of
that required for optimum growth. Similar
improvements in feed:gain ratio, with excess
intake of protein had also been reported
by Combs ( I 965) and Sugahara et al.
( I 969).