Agriculture Reference
In-Depth Information
estimates have been reported in later lactation (Mahan
et al.
, 1971). he other major
protein fraction of colostrum and milk are composed of the major whey proteins.
Total whey protein as a percentage of total protein in sow colostrum starts at 90% at
the time of parturition, when immunoglobulins provide the major fraction of the whey
protein, and then declines to approximately 70% at 24 h postpartum (Csapo
et al.
, 1996;
Klobasa
et al.
, 1987). Total whey protein as a percentage of true protein is between 47 and
50% from day 10 through day 60 of lactation (Csapo
et al.
, 1996).
β-lactoglobulin is the major whey protein in sow milk. Concentrations of β-lactoglobulin
are relatively constant from the colostrum period through at least 7 days of lactation,
ranging between 10 and 15 mg/ml (Hurley and Bryson, 1999; Jackson, 1990). α-lactalbumin
concentrations are lowest in colostrum, at approximately 1.8 to 2.0 mg/ml, and gradually
increase through the first 7 days of lactation to about 3.3 mg/ml (Hurley and Bryson,
1999; Jackson, 1990). Another whey protein in sow milk, whey acidic protein or cysteine-
rich whey protein, increases from approximately 0.3 mg/ml in colostrum to 0.9 mg/ml
in milk from day 7 lactating sows (Hurley and Bryson, 1999; Jackson, 1990). Lactoferrin
concentrations in colostrum at parturition are approximately 1.2 mg/ml, remain elevated
through day 3 of lactation, and then decline to 0.3 mg/ml by day 7, followed by a continued
slow decrease in concentration (Elliot
et al.
, 1984). Concentrations of albumin in sow
colostrum at parturition are 19 mg/ml, then decline to 8 mg/ml by 12 h postpartum,
followed by a further gradual decline to stable concentrations of approximately 2.5 to 3.0
mg/ml during the second and third weeks of lactation (Klobasa and Butler, 1987). Zou
et al.
(1992) also noted several high molecular weight proteins in sow milk by protein gel
analyses. Although these proteins were not identified, they seemed to segregate among
breeds of pigs.
9.7.5
Immunoglobulins
The primary protein components of colostrum are the immunoglobulins, including
the IgG, IgA and IgM isotypes (Hurley and Theil, 2013). Several subclasses of the IgG
isotype have been characterized (Butler
et al.
, 2009), however, most studies determining
colostrum and milk composition quantify total IgG in the secretion. Methods used to
measure the immunoglobulins have ranged from the more classic immunoelectrophoresis
and radial immunodiffusion techniques (Curtis and Bourne, 1971; Frenyo
et al.
, 1981;
Jensen and Pedersen, 1979; Klobasa
et al.
, 1987) to the more recent use of enzyme-linked
immunosorbent assays (ELISA; Foisnet
et al.
, 2010a,b, 2011; Jackson
et al.
, 1995; Loisel
et al.
, 2013; Markowska-Daniel and Pomorska-Mol, 2010; Quesnel
et al.
, 2008; Rolinec
et al.
, 2012).
Concentrations of immunoglobulins are highest in colostrum for the first several hours
postpartum (Table 9.5). Immunoglobulin G, the major immunoglobulin in sow colostrum,
continues at a high concentration for at least the initial 6 h postpartum. By 12 h, IgG
concentrations have declined by nearly 50% compared with those at parturition, and they
continue to decline to approximately 16% and 9% of levels determined at parturition by 24
and 48 h postpartum, respectively. Immunoglobulins A and M follow a similar pattern of
