Agriculture Reference
In-Depth Information
A
B
CH
2
OH
O
H
OH
H
OH
H
HO
HO
HO
OH
O
O
O
O
OH
HO
O
HO
HO
H
H
n
Fig. 7.2
Chemical structure of (A) mannose and (B) mannan oligosaccharides.
bacterial load and pathogenic bacteria of the intestine (of chickens, Fernandez
et al
. 2002;
broiler chickens, Yang
et al
. 2008; dogs, Grieshop
et al
. 2004; pigs, Castillo
et al
. 2008). An
essential step in the bacterial infection process is attachment of pathogens to epithelial cells
(Swanson
et al
. 2002). Carbohydrate-binding proteins such as lectins are present on the exte-
rior of cells and are associated with the antigen recognition and fimbrial adhesins (binding)
of bacteria, especially of Gram-negatives (Engering
et al
. 1997). Lectins bind to the epithe-
lial cells of the gut by attaching to oligosaccharide components of glycoconjugate receptors.
Type-1 fimbrial adhesins, which are common on numerous potentially pathogenic bacterial
species such as members of the Enterobacteriaceae, are specific for mannan residues (Oyofo
et al
. 1989a; Spring
et al
. 2000; Newman 2006). It is suggested that MOS are able to interact
with these receptors by acting as a receptor analogue for type-1 fimbriae and thus prevent-
ing bacterial colonization of the GI tract (Oyofo
et al
. 1989b; Spring 2003; Newman 2006).
Essentially MOS binds to type-1 fimbrial adhesins of potentially pathogenic bacteria (Enter-
obacteriaceae) and prevents them colonizing the GI tract. Furthermore, MOS supplementation
influences immune responses such as increased antibody response against viral infection in
broilers (Shashidhara and Devegowda 2003), decreased peripheral lymphocyte concentrations
in dogs (Grieshop
et al
. 2004) and increased serum IgG and IgM levels and decreased periph-
eral blood T lymphocyte percentage in turkeys (Çetin
et al
. 2005). Later studies with MOS
supplementation in terrestrial animals have shown that MOS work in several different ways
within the digestive tract. MOS can improve gut function and health by increasing the villi
height, uniformity and integrity (in broiler chickens, Iji
et al
. 2001; Hooge 2004; pigs, Castillo
et al
. 2008). As a result, the feed within the digestive tract may be more efficiently digested
leading to a superior nutrient absorption (Spais
et al
. 2003; Sims
et al
. 2004). The effect of
MOS supplementation on the intestinal morphology may explain the improved growth per-
formance in terrestrial animals such as poultry (Shane 2001; Fritts and Waldroup 2003; Yang
et al
. 2008) and pigs (Spring and Privulesku 1998; Miguel
et al
. 2004).
7.3.4 Inulin, oligofructose and fructooligosaccharides
Inulin (IN; Figure 7.3A), oligofructose (OF) and fructooligosaccharides (FOS) belong to
a larger class called IN-type fructans, which refers to all linear fructans containing β-2,1
fructosyl-fructose glycosidic bonds (Kelly 2009). These molecules differ in chain length
and methods of extraction or synthesis. The nomenclature is inconsistent in the literature
(Klosterbuer
et al
. 2011). In general, inulin refers to molecules with an average degree of
polymerization of 2 to 60, while OF and FOS refer to shorter-chain molecules. Inulin, OF
Search WWH ::
Custom Search