Agriculture Reference
In-Depth Information
Table 6.4. Amino acid requirements for maintenance in gestation and lactation, in mg/kg
0.75
(adapted from
NRC, 2012).
Amino acid
Gestation
Lactation
Arginine
17.09
38.45
Histidine
12.09
19.74
Isoleucine
29.78
38.76
Leucine
36.03
53.41
Lysine
34.79
43.26
Methionine
9.17
10.16
Total sulfur
36.80
36.33
Phenylalanine
25.03
35.66
Total aromatic
45.49
62.14
Threonine
44.53
56.78
Tryptophan
10.94
13.97
Valine
69
65.81
N × 6.25
979.33
1,320.51
reproduction, and their relative contribution to the total body protein accretion over the
course of gestation. The five protein pools together define the sow's global body protein
pool, namely the maternal body, the fetal body, the uterus, the placenta and associated
fluids, and the udder. Each of these protein pools has unique amino acid profiles (i.e.
amino acid:lysine), as shown in Table 6.5.
In contrast to many other phases of the life cycle, gestation is characterized by a dynamic
metabolic process whereby different tissues accrete proteins at vastly different rates.
Figure 6.3 illustrates the rate of protein deposition in each of the protein pools in relation
to day of gestation. Fetal and udder growth during gestation share a similar pattern
of protein accretion with a distinct change in accretion rate between d 60 and 80. In
contrast, protein accretion in the placenta and chorioallantoic fluids increases from d
40 to approximately d 60, and remains relatively constant throughout the remainder
of gestation. Finally, the uterus represents the smallest yet significant contribution to
the global protein deposition with a linear increase as gestation advances. Although not
presented per se in this chapter, and indicated earlier, maternal body protein deposition
as a function of day in gestation (i.e. time dependent) and energy intake is quantitatively
more important than fetal protein deposition in first parity sows.
Knowledge of the amino acid profile in each respective protein pool combined with the
daily rate of protein accretion allows the calculation of the total amino acid retention in
the sow's body and in the products of conception on a daily basis, which is an important
contributor to amino acid requirements. Amino acids are not deposited into proteins
with 100% efficiency; for instance, NRC (2012) estimated an efficiency value for lysine
of 49% for gestation. This value is in accordance with data from nitrogen balance studies
