Agriculture Reference
In-Depth Information
Period I (
6
to 21 days)
180
a
160
b
a
140
a
b
b
a
a
120
a
a
a
100
b
a
a
b
a
b
80
b
60
a
b
40
a
b
20
0
Lys
Met+Cys
Thr
Trp
Arg
Gly+Ser
Val
Ile
Leu
His
Phe+Tyr
100
68
70
16
109
156
86
48
119
40
139
Louvain model
100
73
66
17
108
140
77
67
107
36
115
Goettingen approach
Period II (
22
to 37 days)
180
a
160
b
a
a
140
a
b
b
b
120
a
a
a
100
b
a
a
a
a
a
b
80
a
60
b
40
a
b
20
0
Lys
Met+Cys
Thr
Trp
Arg
Gly+Ser
Val
Ile
Leu
His
Phe+Tyr
100
69
68
18
116
158
85
69
130
43
127
Louvain approach
100
71
64
17
105
135
76
67
107
35
114
Goettingen approach
Period III (
38
to 53 days)
180
a
160
b
140
a
a
a
b
a
120
a
a
b
100
a
b
a
a
a
b
80
b
a
60
a
b
40
b
a
20
0
Lys
Met+Cys
Thr
Trp
Arg
Gly+Ser
Val
Ile
Leu
His
Phe+Tyr
100
58
61
16
98
150
65
66
118
39
119
Louvain approach
100
71
65
17
105
135
76
68
107
35
115
Goettingen approach
Fig. 21.1.
The ideal dietary EAA profiles relative to lysine in each age period for fast-growing broilers (Cobb
500) determined using a broken line model with comparative slaughter technique and the Goettingen
approach with a N balance study. Different letters in the graph indicate significant (
P
< 0.05) differences.
Discussion
other EAA. The ratio between the EAAs in
each period using this procedure is presented
In the present study significant differ-
ences (
P
< 0.05) were observed in amino
acid profiles between the two methods in
periods I and II, but in period III they did
not differ significantly (
P
= 0.649). Over the
whole growth period the ideal ratios were
significantly different (
P
< 0.05) when using
the broken line model, but with the Goettin-
gen approach the amino acid ratios in
periods II and III were similar (
P
= 0.287). In
this way we can consider the ratios between
period II and III as comparable to the Goet-
tingen approach.
Amino acids surplus to the animal's require-
ment are degraded and their N is excreted,
and when dietary energy is limiting, amino
acids are oxidized and used as an energy
source. In the present study non-protein
energy was supplied according to the broiler
requirement for age and maintained con-
stantly in diets to prevent energy being a
limiting factor for protein accretion. Also,
in all treatments, apart from those with
amino acid dilutions, all other dietary con-
ditions (e.g. dietary energy and fibre) were
the same. Another point is that the diets in
the dilution method use crystalline AAs to
