Agriculture Reference
In-Depth Information
Table 6.7. Lysine content and amino acid composition of maternal and milk protein expressed as a percentage
of lysine content (adapted from NRC, 2012).
Amino acid
Maternal body
Milk
Lysine (g/100 g CP)
1
6.74
7.01
AA:Lysine
Arginine
105
69
Histidine
47
43
Isoleucine
54
56
Leucine
101
120
Lysine
100
100
Methionine
29
27
Total sulfur
45
50
Phenylalanine
55
58
Total aromatic
97
115
Threonine
55
61
Tryptophan
13
18
Valine
69
71
1
CP = crude protein
robust empirical studies. The efficiency values are essential to calculate the standardized
ileal requirements for essential amino acids in lactation.
6.4.3
Relation between amino acid nutrition and energy nutrition
In sows there are important interactions between energy and amino acid nutrition.
For example in gestating sows, especially during parity 1 to 3 when sows have not yet
achieved their mature body protein mass, a slight increase in daily energy intake from
typical energy intake levels will increase maternal body protein deposition, which in turn
increases the dietary requirements for amino acids (Dourmad
et al.
, 2008; NRC, 2012).
During lactation and when sows are generally in a negative energy balance, an increase in
energy intake will reduce mobilization of both body protein and body lipid (Dourmad
et
al.
, 2008; NRC, 2012). As a consequence, the transfer of amino acids from mobilized body
protein to milk protein is reduced and greater dietary amino acid intakes are needed to
satisfy the requirements for milk protein production (Table 6.3). This interaction between
energy intake and daily amino acid requirements of lactating sows was demonstrated
by Tokach
et al.
(1992), who showed that daily lysine requirements of lactating sows
increase with daily energy intake. Based on these concepts, it is inappropriate to
formulate sow diets by targeting daily amino acid intakes and simply deriving target
amino acid concentration of diets from estimated daily amino acid requirements divided
by feed intake. This calculation may be applicable for finishing pigs or when there is no
relationship between energy intake and lean tissue growth (i.e. body protein accretion).
For sows, it is more reasonable to estimate target amino acid concentration of diets from
