Agriculture Reference
In-Depth Information
Table 15.3.
Mean (±
sd
) amino acid intake (
AAI
) and nitrogen balance (
NB
) of methionine + cystine
(Met+Cys), threonine (Thr), lysine (Lys) and
valine (Val) trials with Bovans White (BovW) and Cobb genotypes
.
Treatment
1
2
7
a
3
4
5
6
AA/
strain
mg/kg
0.73
day
Met
+Cys
AAI
0.0 ± 0.0
39.5 ± 0.95
59.8 ± 1.50
84.8 ± 2.52
166
± 3.84
334 ± 10.1
638 ± 12.1
BovW
c
NB
b
-
296
±
102
-
162
±
119
72.1 ± 80.3
-65.7 ±
174
334 ±
155
615 ±
159
1814 ±
124
Met
+Cys
AAI
0.00 ± 0.0
55.3 ± 2.07
76.2 ± 1.91
120
± 4.05
201
± 10.85
263
± 10.46 316 ± 9.45
Cobb
c
NB
-
230
± 55.4
-97.7 ± 85.2
428 ± 46.2
215
±
96
259
± 69.1
674 ±
166
695 ±
224
Thr
AAI
0.0 ± 0.0
36.7 ± 0.70
96.4 ± 1.25
73.1 ± 1.58
144
± 1.39
287
± 5.89
577 ±
13
BovW
c
NB
-
203
± 36.8
-37.2 ±
109
342 ± 74.1
132
± 73.9
393 ±
170
1182 ± 43.8 1620 ±
184
Thr
AAI
0.0 ± 0.0
38.2 ± 0.59
96.4 ± 1.25
74.9 ± 1.79
152
± 3.22
292
± 5.56
584 ± 5.34
BovW
c
NB
-364 ±
186
-
130
± 91.7
342 ± 74.1
117
± 97.6
487 ± 88.8
509 ±
168
1306 ±
230
Thr
AAI
0.0 ± 0.0
52.6 ± 2.46
95.3 ± 2.49
212
± 9.33
324 ± 3.1
416 ± 7.74
542 ± 15.9
Cobb
c
NB
-305 ±
109
-415 ±
105
468 ± 83.2
51.3 ±
144
597 ±
209
514 ±
269
698 ±
196
Lys
AAI
0.0 ± 0.0
88.0 ± 10.5
132
± 10.6
176
± 14.9
244
± 15.9
338 ± 17.5
-
BovW
d
NB
-387 ±
135
120
± 8.92
139
±
19
313 ± 34.1
635 ± 32.7
794 ± 58.3
-
Val
AAI
0.0 ± 0.0
91.8 ± 45.5
218
± 19.8
222
± 13.8
329 ± 33.4
439 ± 42.2
553 ± 64.8
Cobb
e
NB
-548 ±
260
-
171
± 94.9
-
157
±
134
-47.7 ±
224
346 ± 81.5
493 ±
112
761 ±
138
a
Additional level to verify the limiting amino acid in each trial.
b
Nitrogen balance = nitrogen intake - nitrogen excretion. Nitrogen intake includes the consumption of a N-free diet offered
ad libitum
.
c
Bonato
et al
. (2011).
d
Data not published.
e
Data not published.
Discussion
In order to obtain the different scales
used to describe the maintenance esti-
mates, nitrogen and amino acid intake data
were transformed into their respective
scales based on bird weight (actual, meta-
bolic and protein weights). Considering
that amino acids are required only for pro-
tein, and not for water, fat or mineral main-
tenance, body protein content (mg/
BP
0.73
day)
was considered to be the most accurate.
Figures
of amino acid intake as a function of
NB
and
the regression equations (equation parameter
± standard deviation) on body protein scale
(mg/
BP
0.73
day).
The results obtained in the N balance trials
based on the methodology described by Non-
is and Gous (2008) showed consistent data,
and the scales used helped to improve the
accuracy of the requirement estimates. Be-
cause maintenance is a state in which the
animal is in nitrogen balance; that is, nitro-
gen intake is equal to the sum of nitrogen
losses, thereby maintaining a constant nitro-
gen content in the body (Fuller
et al
., 1976),
amino acids should be supplied at the same
rate as which they are lost (Sakomura and
Rostagno, 2007).
