Agriculture Reference
In-Depth Information
(a)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
(b)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
(c)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
2
4
6
8
10
12
14
16
18
20
Age (weeks)
Fig. 16.4.
The proportions of lysine (a: Lys), methionine + cystine (b: Met+Cys) and threonine (c: Thr) intake
required over time for maintenance and for the deposition of protein in feat
h
er-free body, feathers, ovary,
oviduct and liver. Feather-free body
.
; feather
; ovary
; oviduct
; liver
; and maintenance
The ratio of Met+Cys to Lys changed
from 0.86 in the first week to 0.78 in the 17th
week (
Fig. 16.5)
but over the same period the
Thr:Lys ratio changed very little, remaining
at about 0.72 throughout.
compare the growth of different body com-
ponents of laying pullets from hatching to
the onset of lay. Because of differences in the
rates of growth and amino acid composition
of feather and non-feather protein, these two
components have traditionally been treated
separately when determining the daily amino
acid requirements of growing pullets (Mar-
tin
et al
., 1994). In this exercise the rates
of maturing of these two components were
very similar (0.023 vs 0.024/day), which is
Discussion
The parameters
Pm
,
B
and
t*
of the Gompertz
function were used in this exercise to
