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The emergence of microbial challenges in commercial poultry farming causes significant economic losses. Vaccination is effective in preventing diseases of single aetiology while antibiotics have an advantage over vaccination in controlling diseases of multiple aetiologies. As the occurrence of antibiotic resistance is a serious problem, there is increased pressure on producers to reduce antibiotic use in poultry production. Therefore, it is essential to use alternative substances to cope with microbial challenges in commercial poultry farming. This review will focus on the role of β-glucans originating from yeast cell wall (YCW) as a growth promoter and antibiotic alternative. β-glucans have the ability to modulate the intestinal morphology by increasing the number of goblet cells, mucin expression and cells expressing secretory IgA (sIgA) with increased sIgA in the intestinal lumen and decreased bacterial translocation to different organs. β-glucans also increase the gene expression of tight junction (TJ) proteins which maintain the integrity of the intestinal wall in broiler chickens. However, further studies are required to optimise the dosage and source of β-glucans to determine effects on growth performance and mechanisms against enteric pathogens.
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A review of β-glucans as a growth
promoter and antibiotic alternative
against enteric pathogens in poultry
Department of Pathobiology, Faculty of Veterinary Sciences, Bahauddin Zakariya
University, Multan, Pakistan;
Institute of Pharmacy, Physiology and
Pharmacology, University of Agriculture, Faisalabad, Pakistan
*Corresponding author:
The emergence of microbial challenges in commercial poultry farming causes
signicant economic losses. Vaccination is effective in preventing diseases of
single aetiology while antibiotics have an advantage over vaccination in
controlling diseases of multiple aetiologies. As the occurrence of antibiotic
resistance is a serious problem, there is increased pressure on producers to
reduce antibiotic use in poultry production. Therefore, it is essential to use
alternative substances to cope with microbial challenges in commercial poultry
farming. This review will focus on the role of β-glucans originating from yeast
cell wall (YCW) as a growth promoter and antibiotic alternative. β-glucans have
the ability to modulate the intestinal morphology by increasing the number of goblet
cells, mucin expression and cells expressing secretory IgA (sIgA) with increased
sIgA in the intestinal lumen and decreased bacterial translocation to different
organs. β-glucans also increase the gene expression of tight junction (TJ) proteins
which maintain the integrity of the intestinal wall in broiler chickens. However,
further studies are required to optimise the dosage and source of β-glucans to
determine effects on growth performance and mechanisms against enteric
Keywords: antibiotic alternative; YCW β-glucans; enteric pathogens; poultry
The poultry industry is one of the largest and rapidly growing industries worldwide and
the prevalence of pathogenic microbes challenges practical management and causes
signicant economic losses. Additionally, the downstream industry, including
slaughter, shipping and retail marketing tends to suffer from carcasses contamination
by pathogens (Mainali et al., 2014). Vaccination can prevent diseases of a single
aetiology. Antibiotics have some benets over vaccination when multiple infections
© World's Poultry Science Association 2017
World's Poultry Science Journal, Vol. 73, September 2017
Received for publication September 10, 2016
Accepted for publication February 21, 2017 651
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and environmental stresses produce diseases. Since most antibiotics produced are used in
diets of livestock animals, the increased occurrence of antibiotic resistance in microbes
further limits the use of antibiotics in poultry.
Contemporary international legislation has withdrawn antibiotics in poultry production
as a growth promoter. Consequently, it is necessary to nd alternates for microbial
challenges in domestic fowl. Certain research attention has concentrated on the
possible use of YCW β-glucans in chickens to combat the limitations mentioned
above. Subsequent studies have demonstrated that dietary supplementation of β-
glucans can reduce the severity of enteric pathogen infection (Huff et al., 2006; Shao
et al., 2013), increase phagocytosis by macrophages after bacterial infection (Chen et al.,
2008) and improve growth performance (Cho et al., 2013). Based on the characteristics
of β-glucans, this review will focus on their effects as growth promoters and antibiotic
alternatives against enteric pathogens in poultry.
Yeast cell wall β-glucans
Saccharomyces cerevisiae, is a unicellular yeast that has been developed to be used in
animal feeds (Hooge, 2004; Rosen, 2007). Broiler production can be improved by
maintaining the intestinal integrity with the inclusion of yeast in their diets (Santin et
al., 2001; Zhang et al., 2005; Baurhoo et al., 2007). Typically, the yeast cell wall (YCW)
is composed of β-glucans, mannoproteins, and chitin with varying degrees of
polymerisation, as presented in Table 1.
Table 1 YCW components with their molecular weight and degree of polymerisation (DP).
Macromolecule Cell wall mass Mean molecular weight,
(%, dry weight)
kDa (DP)
Mannoproteins 3540 Highly variable
1,3 β-Glucan 5055 240 (1500)
1,6 β-Glucan 510 24 (150)
Chitin 2 25 (120)
=Klis et al., 2002; Freimund et al., 2003; Lessage and Bussey, 2006; Kwiatkowski et al., 2009.
YCW components, presented in Figure 1, can vary depending upon growth conditions,
time of harvesting (Klis et al., 2002; Aguilar-Uscanga and Francois 2003; Klis et al.,
2006) and most importantly, strains of yeast (Hahn-Hägerdal et al., 2005). In general,
baker's yeast is used for producing high quality β-glucans with good therapeutic
applications (Kim et al., 2007). The processes involved in the separation of β-glucans
have been heavily patented., and there are various methods for separation of β-glucans
from yeasts (Borchani et al., 2016).
β-glucans as a YCW component, are composed with polymerisation of glucose through
β-1,3/1,6 glycosidic linkages. It has the ability to bind with numerous types of cell
surface receptors on macrophages and polymorphonuclear cells (PMNCs) by binding
to Dectin-1 or CR3 receptors (Palićet al., 2006) with subsequent activation of
macrophages/lymphocyte, production of inammatory cytokines, leukotriene,
interleukins and stimulation of phagocytosis for microbial killing (Brown and Gordon,
2003; Brown et al., 2003). Figure 2 demonstrates activation of macrophages by β-
glucans binding to Dectin-1 receptor.
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β-glucans as antibiotic alternative: M.I. Anwar et al.
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Figure 1 Structure of yeast cell wall.
Figure 2 Activation of macrophages by YCW β-glucan binding to Dectin-1 receptor.
Furthermore, YCW β-glucans can modulate the function of neutrophils that assists in
disease resistance. Benets of YCW β-glucans in poultry production can be partially
attributed to enhanced proliferation and phagocytosis by avian macrophages and
heterophils (Guo et al., 2003; Lowry et al., 2005). Broilers fed diets with YCW β-
glucans supplementation showed amplied cell mediated (Chen et al., 2003; Chae et al.,
2006) and humoral immune responses (Guo et al., 2003; Zhang et al., 2008). This
immune enhancing ability can remove Salmonella enterica and Escherichia coli,
economically important pathogens, from the digestive tract (Lowry et al., 2005; Huff
et al., 2010). Furthermore, YCW β-glucans can enhance broiler performance under
unhygienic conditions through increases in villi height, uniformity and integrity,
leading to improved intestinal function and gut health (Huff et al., 2006; Yang et al.,
2007). The YCW β-glucans from different sources have large variations in their structure
that ultimately affect their physiological functions (Volman et al., 2008).
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Alternative to antibiotic growth promoters
Feeds containing no chemical additives are increasingly used in poultry nutrition. Since
antibiotic growth promoters have been discredited by consumer associations, there has
been an increasing trend in formulating diets without supplementation of synthetic drugs
and chemical additives and many scientists are dedicated in nding natural alternatives to
replace antibiotics as growth promoters (Langhout, 2000; Mellor, 2000).
There are numerous studies on the role of YCW β-glucans as growth promoters in
poultry birds. A growth improving effect of YCW β-glucans at 0.1% dietary
supplementation in an unchallenged setting was observed (Cho et al., 2013), which
showed improved body weight gain in broilers compared to control groups. In
another study, Cox et al. (2010b) noted that dietary supplementation with 0.02 or
0.1% β-glucans had no signicant differences on growth performance of broilers with
or without an Eimeria challenge. However, Zhang et al. (2008) reported a growth
improving effect of β-glucan supplemented at 50 and 75 mg/kg in broilers. Rathgeber
et al. (2008) found that 40 ppm yeast β-glucans could increase body weight in broilers
during the grower phase, and an increase in relative weight of the gizzard was observed,
enhancing the digestive capacity of broilers which may account for the growth effect.
Broiler chickens supplemented with 22 ppm β-glucans in feed showed some
improvement when infected by E. coli (Huff et al., 2006). In another study, the
progressive effects of β-glucans were noted in birds reared on litter pen than those in
the cages (Chae et al., 2006). The variations in the results reported could be due to
reasons including differences in the sources of β-glucans (species and strains), purity,
composition, dosage or presence/absence and type of pathogen challenge (Zhang et al.,
2008; Cox et al., 2010b). More studies to optimise the dosage and source of β-glucans for
consistent results in broiler production are required.
β-glucans originating from YCW have different effects on the visceral organs. A study
by Cho et al. (2013) showed that 0.1% dietary supplementation of YCW β-glucans in an
unchallenged trial resulted in an improvement in the relative weight of the spleen and the
bursa of Fabricius. The effects of β-glucans on the relative weight of the spleen and the
bursa of Fabricius varied with studies, depending on the dose and the presence of
pathogen challenges (Rathgeber et al., 2008; Cox et al., 2010a; Salarmoini and
Fooladi, 2011). In another study broilers supplemented with 40-50 mg/kg of β-
glucans in feed showed an increase in the relative weight of the thymus, bursa of
Fabricius and spleen (Guo et al., 2003; Zhang et al., 2008). Chickens supplemented
with mannoprotein and β-glucans showed improved thymus weight (Morales-Lopez et
al., 2009), and β-glucan supplementation improved red blood cells count (Guo et al.,
2003) and increased the villus height of the jejunum mucosa of chickens (Morales-Lopez
et al., 2009), and subsequently may increase the surface area for nutrient absorption.
Further studies are required to delineate the mechanisms of the effect of β-glucans on
primary immune organs and other visceral organs weight in relation to growth
Activity against enteric pathogens
In humans, food-borne gastroenteritis is mainly caused by Salmonella enterica serovar
typhimurium from contaminated poultry products (Zhang et al., 2003; Liljebjelke et al.,
2005). Severe colonisation by Salmonella typhimurium in the gastrointestinal tract can
damage intestinal barriers and may cause bacteremia in both domestic fowls and humans
(Jepson et al., 2000; Zhang et al., 2003; Grifn and McSorley, 2011). Moreover,
654 World's Poultry Science Journal, Vol. 73, September 2017
β-glucans as antibiotic alternative: M.I. Anwar et al.
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Salmonella infection causes high mortality and decreases the production of poultry birds
(Fasina et al., 2008). Colibacillosis, caused by E. coli, is another important enteric
disease in domestic fowl and causes air sacculitis, decreased BW gain, and increased
faecal and carcass contamination (Barnes et al., 2003; Russell, 2003). Gastrointestinal
parasites constitute major stress factors which reduce growth performance and nutrient
utilisation in broilers. Coccidiosis by an intracellular protozoan belonging to the genus
Eimeria (Dalloul and Lillehoj, 2005) can disrupt the intestinal lining resulting in gross
lesions and decreased growth performance by malabsorption of nutrients (Brake et al.,
1997). Controlling these infections is needed for food safety, as well as for both animal
and human health.
Various prophylactic approaches including antibiotics, vaccines, genetic selection for
improved immunity and standard hygienic conditions, are being used to eradicate these
infections from poultry birds (Vandeplas et al., 2010). Dietary supplementation with
yeast β-glucans may be benecial in controlling these challenges.
Defence mechanisms in the gastrointestinal tract (GIT)
In addition to nutrient absorption, the lining of the digestive tract acts as a barrier against
pathogen invasion. Goblet cells secret mucins to attract microbe adhesion to increase
elimination of microbes, and thus prevent physical and chemical injury by pathogens
(Deplancke and Gaskins, 2001; Iijima et al., 2001). When the mucus layer is disturbed,
adhesion of microbes to the intestinal epithelial surface may increase epithelial
permeability and reduce the absorption of nutrients. Intestinal secretory
immunoglobulin A (sIgA) is a line of defence in protecting the intestinal epithelium
from pathogenic microorganisms and maintaining the mucosal layer (Mantis et al., 2011).
Intestinal integrity is maintained by tight junctions (TJ) proteins including claudins,
junctional adhesion molecules and occludin (Tsukita et al., 2001; Schneeberger,
2004). Claudin and occludin families thus maintain intestinal integrity to form a solid
barrier from pathogen invasion (Fanning et al., 1998) as presented in Figure 3 (a).
Damage in GIT due to enteric pathogens
Invasion of enteric pathogens such as Salmonella typhimurium causes loss of integrity
and dysfunction of the intestinal epithelium (Clark et al., 1998; Sears, 2000). Salmonella
typhimurium infection can down regulate TJ protein expression in the intestinal epithelial
cells, damage intestinal barrier function, and thus facilitate bacterial invasion into the
blood stream (Jepson et al., 2000; Kohler et al., 2007). Broilers infected by Salmonella
spp. have been reported to have decreased villi height in the jejunum and altered ratio to
crypt depth, a reduced number of goblet cells with increased sIgA production and its
expressing cells (Beal et al., 2004; Withanage et al., 2005; Rahimi et al., 2009;
Revolledo et al., 2009; Fasina et al., 2010; Marcq et al., 2010; Shao et al., 2013) as
presented in Figure 3(b). Cytokines, including interleukin-6 (IL-6), IL-1β, IL-8 and
interferon-γ, play a pivotal role in the regulation of intestinal TJ barrier with
Salmonella spp. infection (Withanage et al., 2004; Withanage et al., 2005; Fasina et
al., 2008; Al-Sadi, 2009; Groschwitz and Hogan, 2009; Turner, 2009). TJ proteins
including occluding, claudin-1 and claudin-4 expression declined in the jejunum
during Salmonella spp. infection in broilers (Zhang et al., 2012). Decrease of TJ
protein expressions increases epithelial permeability, interrupts intestinal barriers and
allows leakage and invasion of antigens, pathogens and bacterial toxins into the
World's Poultry Science Journal, Vol. 73, September 2017 655
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circulation (Kucharzik et al., 2001; Tsukita et al., 2001; Schneeberger, 2004). Increased
intestinal permeability has been shown to increase the inltration of pathogenic bacteria
into distinct organs including the liver and spleen (Kops et al., 1996; Jepson et al., 2000;
Kohler et al., 2007; Revolledo et al., 2009).
Mechanisms by which β-glucans act as an antibiotic alternative
Yeast β-glucans have been shown to have positive effects against various infectious
diseases by improving immunity, while its role as an antibiotic alternative in domestic
fowl against enteric pathogens is not yet completely explored. β-glucans have various
mechanisms to improve the growth performance of domestic fowls, in which dietary
supplementation has been shown to increase the intestinal clearance of numerous
imperative pathogens such as E. coli and Salmonella spp. (Lowry et al., 2005; Huff
et al., 2010) by protecting intestinal barriers, stimulating phagocytosis and suppressing
pathogen invasion into organs (Lowry et al., 2005). Previous studies have suggested that
β-glucan supplementation can enhance goblet cell number and villus height in the ileum
(de Los Santos et al., 2007; Morales-Lopez et al., 2009), as well as restore villus damage/
loss by Salmonella spp. challenge (Shao et al., 2013). In addition, β-glucans
supplemented at 0.1% level of the diet improved villus height and crypt depth and
their ratio in the duodenum and ileum, upregulated mucin-2 production from goblet
cells, modulated intestinal prole of cytokines, and reduced lesion severity and
inammation in the intestine of broilers during Eimeria/coccidia infection (Cox et al.,
2010a; 2010b). Another mechanism by which YCW β-glucans can act as an antibiotic
alternative is attributed to increased sIgA secretion and numbers of goblet cells that
maintain the integrity of the mucous protective layers for expulsion of enteric
pathogen invasion (Brandtzaeg, 2010). β-glucan supplementation has been shown to
increase jejunal TJ protein expressions such as occluding and claudin-1, leading to the
increased removal of Salmonella Typhimurium (Shao et al., 2013) as illustrated in Figure
3 (c), while it also inhibits the colonisation and invasion of Salmonella in the caeca and
liver, respectively (Lowry et al., 2005; Chen et al., 2008; Revolledo et al., 2009).
These mechanisms of yeast β-glucans relate to the improvement of the intestinal
epithelial cell functions but no mechanism regarding direct killing or binding of β-
glucans with enteric pathogens is available to date. However, various studies relating
to microbial killing by activation of macrophages/lymphocytes are available.
YCW β-glucans can act as a safeguard in domestic fowl against enteric pathogens by
increasing sIgA secretion, goblet cell numbers, upregulating expression of intestinal TJ
proteins and cytokines. Moreover YCW β-glucans merits being considered as a growth
promoter in broilers. As a growth promoter and antibiotic alternative, further studies are
required to optimise the dosage and source of β-glucans to determine its effects on
growth performance and mechanisms against enteric pathogens. In conclusion, β-
glucans may be used as a growth promoter and antibiotic alternative.
656 World's Poultry Science Journal, Vol. 73, September 2017
β-glucans as antibiotic alternative: M.I. Anwar et al.
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Figure 3 Intestinal morphology. (a) normal goblet cells, TJ proteins, sIgA, mucous, intestinal villi, B and
T lymphocytes, plasma and dendritic cells, (b) disruption of TJ proteins, reduced villus height, decreased
goblet cells, mucous, increased sIgA, dendritic cells, plasma cells, T and B lymphocytes by enteric
pathogens, (c) increased goblet cells, mucous, sIgA, T and B lymphocytes, plasma cells, and dendritic cells
with β-glucans and reduced enteric pathogens.
Conict of interest statement
None of the authors of this paper has a nancial or personal relationship with other
people or organisations that could inappropriately inuence or bias the content of the
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AGUILAR-USCANGA, B. and FRANCOIS, J.M. (2003) A study of the yeast cell wall composition and
structure in response to growth conditions and mode of cultivation. Letters in Applied Microbiology 37: 268-
AL-SADI, R. (2009) Mechanism of cytokine modulation of epithelial tight junction barrier. Frontiers in
Bioscience 14: 2765-2778.
BARNES, H.J., VAILLANCOURT, J.P. and GROSS, W.B. (2003) Colibacillosis. Diseases of poultry.
(Ames, IA. USA, Iowa State Press).
BAURHOO, B., PHILLIP, L. and RUIZ-FERIA, C.A. (2007) Effects of puried lignin and mannan
oligosaccharides on intestinal integrity and microbial populations in the ceca and litter of broiler
chickens. Poultry Science 86: 1070-1078.
BEAL, R.K., POWERS, C., WIGLEY, P., BARROW, P.A. and SMITH, A.L. (2004) Temporal dynamics of
the cellular, humoral and cytokine responses in chickens during primary and secondary infection with
Salmonella enterica serovar Typhimurium. Avian Pathology 33: 25-33.
Physical, functional and structural characterisation of the cell wall fractions from baker's yeast Saccharomyces
cerevisiae.Food Chemistry 194: 1149-1155.
(1997) Immunogenic characterisation of a tissue culture-derived vaccine that affords partial protection against
avian coccidiosis. Poultry Science 76: 974-983.
BRANDTZAEG, P. (2010) Update on mucosal immunoglobulin a in gastrointestinal disease. Current Opinion
in Gastroenterology 26: 554-563.
BROWN, G.D. and GORDON, S. (2003) Fungal β-glucans and mammalian immunity. Immunity 19: 311-315.
S. (2003) Dectin-1 mediates the biological effects of β-glucans. The Journal of Experimental Medicine 197:
CHAE, B.J., LOHAKARE, J.D., MOON, W.K., LEE, S.L., PARK, Y.H. and HAHN, T.W. (2006) Effects
of supplementation of β-glucan on the growth performance and immunity in broilers. Research in Veterinary
Science 80: 291-298.
CHEN, H., LI, D., CHANG, B., GONG, L., PIAO, X., YI, G. and ZHANG, J. (2003) Effects of lentinan on
broiler splenocyte proliferation, interleukin-2 production, and signal transduction. Poultry Science 82: 760-
CHEN, K.L., WENG, B.C., CHANG, M.T., LIAO, Y.H., CHEN, T.T. and CHU, C. (2008) Direct
enhancement of the phagocytic and bactericidal capability of abdominal macrophage of chicks by -1,3-
1,6-glucan. Poultry Science 87: 2242-2249.
CHO, J.H., ZHANG, Z.F. and KIM, I.H. (2013) Effects of single or combined dietary supplementation of β-
glucan and ker on growth performance, blood characteristics and meat quality in broilers. British Poultry
Science 54: 216-221.
CLARK, M.A., HIRST, B.H. and JEPSON, M.A. (1998) Inoculum composition and salmonella
pathogenicity island 1 regulate m-cell invasion and epithelial destruction by salmonella typhimurium.
Infection and Immunity 66: 724-731.
COX, C.M., STUARD, L.H., KIM, S., MCELROY, A.P., BEDFORD, M.R. and DALLOUL, R.A. (2010a)
Performance and immune responses to dietary beta-glucan in broiler chicks. Poultry Science 89: 1924-1933.
(2010b) Immune responses to dietary beta-glucan in broiler chicks during an eimeria challenge. Poultry
Science 89: 2597-2607.
DALLOUL, R.A. and LILLEHOJ, H.S. (2005) Recent advances in immunomodulation and vaccination
strategies against coccidiosis. Avian Diseases 49: 1-8.
DONOGHUE, D.J. (2007) Gastrointestinal maturation is accelerated in turkey poults supplemented with
a mannan-oligosaccharide yeast extract (alphamune). Poultry Science 86: 921-930.
DEPLANCKE, B. and GASKINS, H. (2001) Microbial modulation of innate defense: Goblet cells and the
intestinal mucus layer. The American Journal of Clinical Nutrition 73: 1131S1141S.
FANNING, A.S., JAMESON, B.J., JESAITIS, L.A. and ANDERSON, J.M. (1998) The tight junction
protein zo-1 establishes a link between the transmembrane protein occludin and the actin cytoskeleton.
Journal of Biological Chemistry 273: 29745-29753.
FASINA, Y.O., HOERR, F.J., MCKEE, S.R. and CONNER, D.E. (2010) Inuence of Salmonella enterica
serovar Typhimurium infection on intestinal goblet cells and villous morphology in broiler chicks. Avian
Diseases 54: 841-847.
658 World's Poultry Science Journal, Vol. 73, September 2017
β-glucans as antibiotic alternative: M.I. Anwar et al.
available at
Downloaded from IP address:, on 22 Aug 2017 at 09:42:08, subject to the Cambridge Core terms of use,
FASINA, Y.O., HOLT, P.S., MORAN, E.T., MOORE, R.W., CONNER, D.E. and MCKEE, S.R. (2008)
Intestinal cytokine response of commercial source broiler chicks to Salmonella Typhimurium infection.
Poultry Science 87: 1335-1346.
FREIMUND, S., SAUTER, M., KÄPPELI, O. and DUTLER, H. (2003) A new non-degrading isolation
process for 1,3-b-D-glucan of high purity from baker's yeast Saccharomyces cerevisiae.Carbohydrate
Polymers 54: 159-171.
GRIFFIN, A.J. and MCSORLEY, S.J. (2011) Development of protective immunity to salmonella, a mucosal
pathogen with a systemic agenda. Mucosal Immunology 4: 371-382.
GROSCHWITZ, K.R. and HOGAN, S.P. (2009) Intestinal barrier function: Molecular regulation and disease
pathogenesis. Journal of Allergy and Clinical Immunology 124: 3-20.
GUO, Y., ALI, R.A. and QURESHI, M.A. (2003) The inuence of β-glucan on immune responses in broiler
chicks. Immunopharmacology and Immunotoxicology 25: 461-472.
J. and VAN ZYL, W.H. (2005) Role of cultivation media in the development of yeast strains for large scale
industrial use. Microbial Cell Factories 4: 31.
HOOGE, D.M. (2004) Meta-analysis of broiler chicken pen trials evaluating dietary mannan oligosaccharide,
19932003. International Journal of Poultry Science 3: 163-174.
DONOGHUE, A.M. (2010) Bacterial clearance, heterophil function, and hematological parameters of
transport-stressed turkey poults supplemented with dietary yeast extract. Poultry Science 89: 447-456.
HUFF, G.R., HUFF, W.E., RATH, N.C. and TELLEZ, G. (2006) Limited treatment with -1,3/1,6-glucan
improves production values of broiler chickens challenged with Escherichia coli.Poultry Science 85: 613-
IIJIMA, H., TAKAHASHI, I. and KIYONO, H. (2001) Mucosal immune network in the gut for the control
of infectious diseases. Reviews in. Medical Virology 11: 117-133.
JEPSON, M.A., SCHLECHT, H.B. and COLLARES-BUZATO, C.B. (2000) Localisation of dysfunctional
tight junctions in Salmonella enterica serovar Typhimurium-infected epithelial layers. Infection and Immunity
68: 7202-7208.
KIM, Y.H., KANG, S.W., LEE, J.H., CHANG, H.L., YUN, C.W., PAIK, H.D., KANG, C.W. and KIM, S.
W. (2007) High density fermentation of Saccharomyces cerevisiae jul3 in fed-batch culture for the production
of β-glucan. Journal of Industrial and Engineering Chemistry 13: 153-158.
KLIS, F.M., BOORSMA, A. and DE GROOT, P.W.J. (2006) Cell wall construction in Saccharomyces
cerevisiae.Yeast 23: 185-202.
KLIS, F.M., MOL, P., HELLINGWERF, K. and BRUL, S. (2002) Dynamics of cell wall structure in
Saccharomyces cerevisiae.FEMS Microbiology Reviews 26: 239-256.
B.A. (2007) Salmonella enterica serovar Typhimurium regulates intercellular junction proteins and facilitates
transepithelial neutrophil and bacterial passage. AJP: Gastrointestinal and Liver Physiology 293: G178-G187.
KOPS, S.K., LOWE, D.K., BEMENT, W.M. and WEST, A.B. (1996) Migration of Salmonella typhi through
intestinal epithelial monolayers: Anin vitrostudy. Microbiology and Immunology 40: 799-811.
KUCHARZIK, T., WALSH, S.V., CHEN, J., PARKOS, C.A. and NUSRAT, A. (2001) Neutrophil
transmigration in inammatory bowel disease is associated with differential expression of epithelial
intercellular junction proteins. The American Journal of Pathology 159: 2001-2009.
KWIATKOWSKI, S., THIELEN, U., GLENNY, P. and MORAN, C. (2009) A study of Saccharomyces
cerevisiae cell wall glucans, The Institute of Brewing & Distilling 115 (2): 151-158.
LANGHOUT, P. (2000) New additives for broiler chickens. World Poultry-Elsevier 16 (3): 22-27.
LESSAGE, G. and BUSSEY, H. (2006) Cell wall assembly in Saccharomyces cerevisiae.Microbiology and
Molecular Biology Reviews 70 (2): 317-343.
J.J. (2005) Vertical and horizontal transmission of Salmonella within integrated broiler production system.
Foodborne Pathogens and Disease 2: 90-102.
(2005) Puried β-glucan as an abiotic feed additive up-regulates the innate immune response in immature
chickens against Salmonella enterica serovar Enteritidis. International Journal of Food Microbiology 98:
MAINALI, C., MCFALL, M., KING, R. and IRWIN, R. (2014) Evaluation of antimicrobial resistance
proles of salmonella isolates from broiler chickens at slaughter in Alberta, Canada. Journal of Food
Protection 77: 485-492.
MANTIS, N.J., ROL, N. and CORTHÉSY, B. (2011) Secretory iga's complex roles in immunity and mucosal
homeostasis in the gut. Mucosal Immunology 4: 603-611.
World's Poultry Science Journal, Vol. 73, September 2017 659
β-glucans as antibiotic alternative: M.I. Anwar et al.
available at
Downloaded from IP address:, on 22 Aug 2017 at 09:42:08, subject to the Cambridge Core terms of use,
MARCQ, C., COX, E., SZALO, I.M., THEWIS, A. and BECKERS, Y. (2010) Salmonella typhimurium oral
challenge model in mature broilers: Bacteriological, immunological, and growth performance aspects. Poultry
Science 90: 59-67.
MELLOR, S. (2000) Nutraceuticals-alternatives to antibiotics. World Poultry-Elsevier 16 (2): 30-33.
Use of yeast cell walls; -1, 3/1, 6-glucans; and mannoproteins in broiler chicken diets. Poultry Science 88:
Immunomodulatory effects of β-glucan on neutrophil function in fathead minnows (pimephales promelas
ranesque, 1820). Developmental & Comparative Immunology 30: 817-830.
RAHIMI, S., GRIMES, J.L., FLETCHER, O., OVIEDO, E. and SHELDON, B.W. (2009) Effect of a
direct-fed microbial (primalac) on structure and ultrastructure of small intestine in turkey poults. Poultry
Science 88: 491-503.
(2008) Growth performance and spleen and bursa weight of broilers fed yeast beta-glucan. Canadian
Journal of Animal Science 88: 469-473.
REVOLLEDO, L., FERREIRA, C.S.A. and FERREIRA, A.J.P. (2009) Prevention of Salmonella
Typhimurium colonisation and organ invasion by combination treatment in broiler chicks. Poultry Science
88: 734-743.
ROSEN, G.D. (2007) Holo-analysis of the efcacy of bio-mos® in broiler nutrition. British Poultry Science 48:
RUSSELL, S. (2003) The effect of airsacculitis on bird weights, uniformity, fecal contamination, processing
errors, and populations of campylobacter spp. And Escherichia coli.Poultry Science 82: 1326-1331.
SALARMOINI, M. and FOOLADI, M. (2011) Efcacy of lactobacillus as probiotic to improve broiler chicks
performance. Journal of Agriculture Science and Technology 13: 165-172.
MYASAKA, A.M. (2001) Performance and intestinal mucosa development of broiler chickens fed diets
containing Saccharomyces cerevisiae cell wall. The Journal of Applied Poultry Research 10: 236-244.
SCHNEEBERGER, E.E. (2004) The tight junction: A multifunctional complex. AJP: Cell Physiology 286:
SEARS, C.L. (2000) Molecular physiology and pathophysiology of tight junctions v. Assault of the tight
junction by enteric pathogens. The American Journal of Physiology-Gastrointestinal and Liver Physiology
279: G1129-G1134.
SHAO, Y., GUO, Y. and WANG, Z. (2013) -1,3/1,6-glucan alleviated intestinal mucosal barrier impairment of
broiler chickens challenged with Salmonella enterica serovar Typhimurium. Poultry Science 92: 1764-1773.
TSUKITA, S., FURUSE, M. and ITOH, M. (2001) Nature Reviews Molecular Cell Biology 2: 285-293.
TURNER, J.R. (2009) Intestinal mucosal barrier function in health and disease. Nature Reviews Immunology 9:
and THEWIS, A. (2010) Erratum to "efciency of a lactobacillus plantarum-xylanase combination on
growth performances, microora populations, and nutrient digestibilities of broilers infected with
Salmonella Typhimurium" (Poultry Science 88: 1643-1654). Poultry Science 89: 1569-1569.
VOLMAN, J.J., RAMAKERS, J.D. and PLAT, J. (2008) Dietary modulation of immune function by β-
glucans. Physiology & Behavior 94: 276-284.
BARROW, P., SMITH, A., MASKELL, D. and MCCONNELL, I. (2004) Rapid expression of
chemokines and proinammatory cytokines in newly hatched chickens infected with Salmonella enterica
serovar Typhimurium. Infection and Immunity 72: 2152-2159.
BEAL, R., BARROW, P., MASKELL, D. and MCCONNELL, I. (2005) Cytokine and chemokine
responses associated with clearance of a primary Salmonella enterica serovar Typhimurium infection in
the chicken and in protective immunity to rechallenge. Infection and Immunity 73: 5173-5182.
YANG, Y., IJI, P.A., KOCHER, A., MIKKELSEN, L.L. and CHOCT, M. (2007) Effects of
mannanoligosaccharide on growth performance, the development of gut microora, and gut function of
broiler chickens raised on new litter. The Journal of Applied Poultry Research 16: 280-288.
ZHANG, A.W., LEE, B.D., LEE, S.K., LEE, K.W., AN, G.H., SONG, K.B. and LEE, C.H. (2005) Effects
of yeast (Saccharomyces cerevisiae) cell components on growth performance, meat quality, and ileal mucosa
development of broiler chicks. Poultry Science 84: 1015-1021.
ZHANG, B., GUO, Y. and WANG, Z. (2008) The modulating effect of 1,3/1,6-glucan supplementation in the
diet on performance and immunological responses of broiler chickens. Asian-Australasian Journal of Animal
Sciences 21: 237-244.
660 World's Poultry Science Journal, Vol. 73, September 2017
β-glucans as antibiotic alternative: M.I. Anwar et al.
available at
Downloaded from IP address:, on 22 Aug 2017 at 09:42:08, subject to the Cambridge Core terms of use,
ZHANG, B., SHAO, Y., LIU, D., YIN, P., GUO, Y. and YUAN, J. (2012) Zinc prevents Salmonella enterica
serovar Typhimurium-induced loss of intestinal mucosal barrier function in broiler chickens. Avian Pathology
41: 361-367.
Molecular pathogenesis of Salmonella enterica serotype Typhimurium-induced diarrhea. Infection and
Immunity 71: 1-12.
World's Poultry Science Journal, Vol. 73, September 2017 661
β-glucans as antibiotic alternative: M.I. Anwar et al.
available at
Downloaded from IP address:, on 22 Aug 2017 at 09:42:08, subject to the Cambridge Core terms of use,
... Bacterial infections are important diseases in humans and animals that can be treated using antibacterial drugs; however, increasing global awareness of the side effects of chemical-based drugs resulted in an attitude to use natural ingredients to prevent such diseases and utilization of immune stimulants to boost the immune system of the body against these infections has been increased. Administration of BG can be helpful in enhancing the clearance of bacteria, advanced bactericidal activity, more cytokine production modulation, and increasing neutrophils and monocytes number, which all lead to an antibiotic activity (Anwar et al. 2017). It should be noted that the immunomodulation function of BG can be upregulated by both parenteral and oral applications (Daou and Zhang 2012). ...
... Enhanced sIgA secretion and goblet cells number might also lead to the integrity of the mucous protective layers and expel invasive pathogens (Brandtzaeg 2010). Direct killing or biding mechanism of BG against pathogens was not reported yet (Anwar et al. 2017). Schwartz and Vetvicka (2021 reviewed the application of BGas (an alternative to antibiotics) in poultry against the most frequently intestinal infections such as those from E. coli, Salmonella typhimurium, and Clostridium perfringens. ...
Gut microbiota (GMB) in humans plays a crucial role in health and diseases. Diet can regulate the composition and function of GMB which are associated with different human diseases. Dietary fibers can induce different health benefits through stimulation of beneficial GMB. β-glucans (BGs) as dietary fibers have gained much interest due to their various functional properties. They can have therapeutic roles on gut health based on modulation of GMB, intestinal fermentation, production of different metabolites, and so on. There is an increasing interest in food industries in commercial application of BG as a bioactive substance into food formulations. The aim of this review is considering the metabolizing of BGs by GMB, effects of BGs on the variation of GMB population, influence of BGs on the gut infections, prebiotic effects of BGs in the gut, in vivo and in vitro fermentation of BGs and effects of processing on BG fermentability.
... Horst et al. (2019) stated that dietary b-glucan can improve the host immunological response to Newcastle vaccinations. Furthermore, b-glucan extracted from yeast increases the number of cells releasing immunoglobulin A (IgA) and could, therefore, substitute for antibiotics in the treatment of certain enteric pathogens in poultry (Anwar et al., 2017). S. cerevisiae can also increase the phosphorus and crude protein and decrease the fiber content in the feed. ...
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Poultry production has been developing in Vietnam with challenges of disease. Thus, feed additive should be investigated not only growth but also health enhancement. Here, we aimed to determine the effects of Saccharomyces cerevisiae-fermented rice (FR) and β-glucan on turkey's growth performance, carcass characteristics, immune and fatty acid (FA) profiles. A total of 180 turkey chicks aged 1-56 days were randomly assigned to five sextuplicate groups and the birds had ad libitum feed and water access throughout the experiment. The five treatment groups were given the same diet with different proportions of FR and β-glucan. Broilers supplemented with 4% β-glucan and 4% FR presented the highest and second-highest growth performance, respectively. The 4% β-glucan and 4% FR treatments resulted in the highest carcass characteristic values without significantly affecting the breast or thigh meat pH or cooking loss. The 4% β-glucan and 4% FR treatments maximally increased the Newcastle disease (ND) antibody titers at 28, 42 and 56 days, respectively as well as thymus organ index. The foregoing treatments did not significantly affect the blood profiles relative to the control. However, the 4% FR treatment lowered the blood cholesterol levels (p > 0.05). The total FA profiles did not significantly differ among treatments. Nevertheless, both the β-glucan and FR treatments increased the MUFA levels compared to that of the control (p > 0.05). Hence, the dietary administration of 4% β-glucan and FR to turkey broilers could effectively improve their growth performance and immunity.
... Main theories on yeast cell wall interactions with mycotoxins (adapted from Luo et al.42 and Anwar et al.240 ) ...
Fungi-induced postharvest diseases are the leading causes of food loss and waste. In this context, fruit decay can be directly attributed to phytopathogenic and/or mycotoxin-producing fungi. The U.N. Sustainable Development Goals aim to end hunger by 2030 by improving food security, sustainable agriculture, and food production systems. Antagonistic yeasts are one of the methods presented to achieve these goals. Unlike physical and chemical methods, harnessing antagonistic yeasts as a biological method controls the decay caused by fungi and adsorbs and/or degrades mycotoxins sustainably. Therefore, antagonistic yeasts and their antifungal mechanisms have gained importance. Additionally, mycotoxins' biodetoxification is carried out due to the occurrence of mycotoxin-producing fungal species in fruits. Combinations with processes and agents have been investigated to increase antagonistic yeasts' efficiency. Therefore, this review provides a comprehensive summary of studies on preventing phytopathogenic and mycotoxigenic fungi and their mycotoxins in fruits, as well as biocontrolling and biodetoxification mechanisms.
... Glucan is as important a component of YG as MOS. Our results are consistent with previous studies that reported that glucan and MOS attenuated barrier dysfunction and enhanced gut health in broiler chickens (41). Nevertheless, the possible mechanism by which yeast products regulate the intestinal physical barrier is unknown. ...
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The active ingredients extracted from yeast are important for regulating animal health. The aim of the current research was to explore the impacts of dietary yeast glycoprotein (YG) on the growth performance, intestinal morphology, antioxidant capacity, immunity and disease resistance of largemouth bass ( Micropterus salmoides ). A total of 375 juvenile fish (6.00 ± 0.03 g) were allocated into 15 fiberglass tanks. Triplicate tanks were assigned to each diet. The dietary YG inclusion was as follows: the first group was given a high fishmeal diet (40% fishmeal, 0% YG) (FM) and the second group was given a low fishmeal diet (30% fishmeal and 15% soybean meal, 0% YG) (LFM). The fish in the third, fourth and fifth groups were fed the LFM diet supplemented with 0.5% (LFM+YG0.5), 1.0% (LFM+YG1.0) and 2.0% (LFM+YG2.0) YG, respectively. After a 60- day feeding trial, a challenge test using A. hydrophila was carried out. The results showed that the final body weight (FBW) and weight gain rate (WGR) in the LFM+YG2.0 group were significantly higher than those in the LFM group and were no significantly different from those in the FM group. This may be partially related to the activation of the target of rapamycin (TOR) signaling pathway. Dietary YG supplementation enhanced intestinal physical barriers by upregulating the intestinal tight junction protein related genes ( claudin1 , occludin and zo2 ) and improving the structural integrity of the gut, which may be partially associated with AMPK signaling pathway. Moreover, dietary YG increased the antioxidant capacity in the gut, upregulated intestinal anti-inflammatory factors ( il-10 , il1-1β and tgf-β ) and downregulated proinflammatory factors ( il-1β and il-8 ), which may be partially related to the Nrf2/Keap1 signaling pathways. The results of the challenge test indicated that dietary supplementation with 0.5 or 1.0% YG can increase the disease tolerance of largemouth bass against A. hydrophila . In conclusion, the present results indicated that dietary supplementation with YG promotes the growth performance, intestinal immunity, physical barriers and antioxidant capacity of largemouth bass. In addition, 1.0% of dietary YG is recommended for largemouth bass based on the present results.
... Architecture de la paroi de S. cerevisiae[4]. ...
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All living organisms, including walled cells, exhibit key characteristics such as differentiation, growth, and reproduction. An understanding of these features in normal and/or pathological contexts is inextricably linked to the cell-wall ; an elastic sturdy structure which constitutes the outermost boundary of the cell. The cell-wall affords mechanical protection, dictates cell shape, and provides a counter force against the inner turgor pressure. This thesis deals specifically with Saccharomyces cerevisiae yeast which constitutes a well-established model system to decipher fundamental processes relevant to eukaryotic cells. The first part of this thesis addresses the cell-wall mechanical properties. To this end, a viscoelasticmodel has been developed within the finite strain range due to the soft nature of the yeasts. Such cells were considered to be thin walled, liquid-filled, axisymmetric structures. To describe the delayed response of the cell, a hyperelastic behavior was coupled with a creep-like potential where the evolution equation of the strain-like internal variables is in accordance with the continuum thermodynamics requirements. The inner fluid of the cell is taken to be incompressible and is represented by a normal pressure load on the inner surface of the cell-wall. Follower loads are used at this stage, the amplitudes of which are implicitly accounted for by the use of the constant inner volume constraint. Using a combined theoretical, numerical and experimental approach, the viscoelastic cell-wall parameters have been identified. Different mechanical properties of the cell-wall have been found by the use, on the one hand, of the atomic force microscopy and, on the other hand, of a micromanipulation-like technique. The necessityof a cell-wall representation by at least two sets of layers with sensitively different mechanical properties has been established. Numerical simulations have been conducted concomitantly in solid and shell approaches to highlight the efficiency of the proposed framework. The second part of this thesis focuses on the growth of budding yeast powered by the turgor pressure. A theoretical model has been developed in a solid approach to describe the emergence of the bud and its evolution over time. From the purely mechanical point of view, to control bud formation, two essential parameters have been involved in the evolution equation : a characteristic time, and a stress-like threshold. Afterwards, the model has been extended to the shell approach. Later on, the modelling framework has been improved by simulating the contractile ring formed at the base of the protrusion region as a natural growth phenomenon. The whole framework has been qualitatively evaluated by the use of a finite element modeling.
... The addition of GLC to feed enhanced gut health and disease resistance in birds challenged with necrotic enteritis by stimulating the gene expression of antimicrobial peptides [13]. By enhancing the populations of cells secreting IgA and goblet cells, yeastbased GLC can serve as growth inducers and prospective antibiotic alternatives against specific microorganisms in birds [14]. Moreover, macrophages obtained from chickens fed a diet supplemented with GLC showed upregulated expression of IL-1 [15], IL-2, interferon (IFN)-γ [16], IL-4, and IL-18 [17]. ...
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Recently, researchers have been intensively looking for novel, safe antibiotic alternatives because of the prevalence of many clinical and subclinical diseases affecting bird flocks and the risks of using antibiotics in subtherapeutic doses as feed additives. The present study intended to evaluate the potential use of 1,3-β-glucans (GLC) as antibiotic alternative growth promotors and assessed the effect of their dietary inclusion on the growth performance, carcass traits, chemical composition of breast muscles, economic efficiency, blood biochemical parameters, liver histopathology, antioxidant activity, and the proinflammatory response of broiler chickens. This study used 200 three-day- old ROSS broiler chickens (50 chicks/group, 10 chicks/replicate, with an average body weight of 98.71 ± 0.17 g/chick). They were assigned to four experimental groups with four dietary levels of GLC, namely 0, 50, 100, and 150 mg kg−1 , for a 35-day feeding period. Birds fed diets containing GLC showed an identical different growth rate to the control group. However, the total feed intake (TFI) increased quadratically in the GLC50 and GLC100 groups as compared to that in the control group. GLC addition had no significant effect on the weights of internal and immune organs, except for a decrease in bursal weight in the GLC150 group (p = 0.01). Dietary GLC addition increased the feed cost and total cost at 50 and 100 mg kg−1 doses. The percentages of n-3 and n-6 PUFA in the breast muscle of broiler chickens fed GLC-supplemented diets increased linearly in a dose- dependent manner (p < 0.01). The serum alanine aminotransferase (ALT) level and the uric acid level were quadratically increased in the GLC150 group. The serum levels of total antioxidant capacity, catalase, superoxide dismutase, interleukin-1β, and interferon-gamma linearly increased, while the MDA level decreased in the GLC-fed groups in a dose-dependent manner. Normal histological characterization of different liver structures in the different groups with moderate round cells was noted as a natural immune response around the hepatic portal area. The different experimental groups showed an average percentage of positive immunostaining to the proinflammatory marker transforming growth factor-beta with an increase in the dose of GLC addition. The results suggest that GLC up to 100 mg kg−1 concentration can be used as a feed additive in the diets of broiler chickens and shows no adverse effects on their growth, dressing percentage, and internal organs.GLC addition in diets improves the antioxidant activity and immune response in birds. GLC help enrich the breast muscle with n-3 and n-6 polyunsaturated fatty acids.
... El papel de los antibióticos entéricos [165]. Los probióticos o Direc-fed Microbials (DFM), como se encuentran en la literatura, son una parte de microorganismos vivos, enzimas libres, minerales traza y coadyuvantes en un portador comestible, esta especie es muy útil cuando el animal sufre altos grados de estrés, lo cual afecta la salud, por ejemplo, cuando el ave es sometida a cambios de clima bruscos podría bajar la calidad de la carne de forma significativa [166], los probióticos presentan beneficios en el tracto intestinal del ave al restringir la colonización [28], [167], [168]. ...
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Tema y alcance: Las implicaciones de factores externos dentro de la seguridad alimentaria crea afectaciones que ponen en riesgo la inocuidad de los alimentos cárnicos avícolas, la investigación de las principales bacterias como Salmonella sp, Campylobacter sp y E. coli son de suma importancia, debido a que aportan para la mitigación de estos microorganismos durante la cadena de producción. Características: Se realizó una revisión literaria de artículos científicos, con el interés de recopilar información pertinente a los productos avícolas, agentes externos, brotes relacionados por consumo de pollo y estrategias actuales más comunes que reducen infecciones a la población. Hallazgos: un crecimiento en el consumo de carne de ave, donde surge la necesidad de garantizar un control de posibles puntos de infección en las diferentes partes de fabricación del cárnico avícola, para esto último se evidencia de la efectividad del uso de los antibióticos, prebióticos y probióticos como mecanismos de saneamientos del alimento. Conclusión: a pesar de los avances en la investigación de los patógenos y mejoramientos del proceso en las diferentes etapas de producción aún persisten infecciones referentes al consumo de carne de pollo.
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This investigation was designed to determine the effect of Saccharomyces cerevisiae (S. cerevisiae) supplementation on production variables, carcass characteristics, internal organ weights, gut linear measurements, digesta pH values, haematology and serum biochemical indices of Boschveld chickens. The biochemical composition, mineral and amino acid profiles of S. cerevisiae were analysed. A total of six hundred (n = 600) day-old, unsexed, healthy Boschveld chicks were distributed randomly to six (n = 6) dietary treatments. Each group (treatment) consisted of five (n = 5) replicates of 20 chicks each in a complete randomised design. The feeding programme consisted of commercial broiler starter (1 to 49 days) and grower (50 to 91 days) mash feeds. During each feeding phase, dietary treatments had the same caloric density and the same protein level, but with different levels of S. cerevisiae – as follows: Y0 (0.0), Y1 (2.5), Y2 (5.0), Y3 (7.5), Y4 (10.0) and Y5 (12.5) g kg-1 feed. A quadratic function was deployed to estimate the ideal levels of S. cerevisiae for optimal response of different variables. A linear function was used to establish the relationship between response variables and dietary S. cerevisiae. Pearson's correlation coefficient (r) was used to establish the association among production variables. Proximate results revealed that S. cerevisiae had high crude protein (49.6 %) content, moderate carbohydrate (36.15%) and low crude fibre (2.90 %) content. The mineral analysis showed that phosphorus (1.20) and potassium (0.85) g 100g-1 were the highest minerals in S. cerevisiae. Glutamic acid and aspartic acid were the main amino acids in S. cerevisiae and accounted for 52.33 % of the total dispensable amino acids. Results also showed that S. cerevisiae is dominated by hydrophilic and acidic amino acids. Dietary probiotic S. cerevisiae did not influence (p>0.05) feed intake (FI) and metabolisable energy (ME), but boosted (p<0.05) average daily gain (ADG), feed conversion ratio (FCR), live weight (LW) and nitrogen retention (NR) of Boschveld chickens. Dietary probiotic S. cerevisiae influenced (p<0.05) some carcass characteristics, internal organ weights, linear measurements and digesta pH values of the gastrointestinal tract of Boschveld chickens. Dietary probiotic S. cerevisiae had a significant effect (p<0.05) on packed cell volume (PCV), haemoglobin (Hb), mean corpuscular haemoglobin (MCH), total protein, cholesterol and triglyceride. However, it did not influence (p>0.05) red blood cells (RBCs) count, mean corpuscular volume (MCV), mean corpuscular Hb concentration (MCHC), platelets, white blood cells (WBCs) count, heterophils, lymphocytes, monocytes, albumen, glucose and uric acid. Strong positive relationships were observed between S. cerevisiae levels and PCV, Hb and MCV values. Production variables, carcass and internal organ parameters were optimised at different S. cerevisiae supplementation levels. The S. cerevisiae supplementation level for optimal productivity decreased as Boschveld chickens grew older. Based on the results reported here, S. cerevisiae inclusion in the diet of Boschveld chickens had no adverse effects and can be used as a natural growth promoter.
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The gastrointestinal epithelium is covered by a protective mucus gel composed predominantly of mucin glyco-proteins that are synthesized and secreted by goblet cells. Changes in goblet cell functions and in the chemical composition of intestinal mucus are detected in response to a broad range of luminal insults, including alterations of the normal microbiota. However, the regulatory networks that mediate goblet cell responses to intestinal insults are poorly defined. The present review summarizes the results of developmental, gnotobiotic, and in vitro studies that showed alterations in mucin gene expression, mucus composition, or mucus secretion in response to intestinal microbes or host-derived inflammatory mediators. The dynamic nature of the mucus layer is shown. Available data indicate that intestinal microbes may affect goblet cell dynamics and the mucus layer directly via the local release of bioactive factors or indirectly via activation of host immune cells. A precise defini-tion of the regulatory networks that inteface with goblet cells may have broad biomedical applications because mucus alter-ations appear to characterize most diseases of mucosal tissues.
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Use of antibiotics as an additive in poultry diets to improve growth has been discussed in relation to bacterial resistance and the development of new products and management practices. This study was carried out to test the efficacy of a new substance (Saccharomyces cerevisiae cell walls, var. Calsberg- SCCW) obtained from the brewery industry, added (at 0.1 and 0.2%) to broiler chicken diets (based on corn and soybean meal), on performance and intestinal mucosa development In Experiment 1 (carried out in litter-floor pens) the results revealed higher body weight gain for the total experimental period and higher villus height at 7 d of age for the birds fed 0.2% SCCW. In a field test using 44,000 broilers that received feed containing 0.2% SCCW, the results also showed higher body weight gain and better feed conversion for SCCW-supplemented birds. The present findings show that SCCW improved body weight gain in broiler chickens and that this effect can be attributed to the trophic effect of this product on the intestinal mucosa, because it increases villus height, particularly during the first 7 d of a chicken's life.
This study evaluated the efficacy of a yeast beta-glucan product (YBG) as a growth-promoting feed ingredient for broilers. Two trials were conducted with day-old chicks assigned to 24 pens (38 birds/pen) and one of three diets: no growth promotant, virginiamycin, or YBG. On days 14 and 38, two birds per pen were euthanized and the spleen and bursa of Fabricius were removed. In the first trial, body weights of birds from each treatment were the same until 38 d, when control birds were smaller (P<0.05). In the second trial, 38-d body weights were the same for all treatments. A third trial was conducted with half the number of pens per treatment. In the third trial, controls were smaller than YBG at 38 d, but not smaller than virginiamycin. Feed conversion was not affected by diet in trials 2 and 3 but for trial 1 the control birds had poorer conversion than virginiamycin (P<0.05), but not worse than YBG. Spleen weights were not different between treatment groups. Bursa weights decreased with age for all treatments in trials 2 and 3, but not in trial 1 for controls. These results indicate that YBG is as effective as virginiamycin in promoting growth of broiler chickens.
The object of this trial was to investigate the effect of dietary β-1,3/1,6-glucan supplementation on the performance and immunological response of broiler chickens. Two hundred and forty 1-day old male broilers (39±1 g) were separated into six treatments which were given six different feeds containing 0 (control), 25, 50, 75, 100 and 125 mg/kg dietary β-1,3/1,6-glucan supplementation. On days 21 and 42, body weight gain, feed consumption and feed conversation rate were recorded as measures of growth performance. The levels of key cytokines in the immuno-regulating pathway: interleukin-1 (IL-1), interleukin-2 (IL-2), interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), and the concentrations of signal molecules: peripheral blood plasma globulin, serum Immunoglobulin G (IgG) and intestinal secretary Immunoglobulin A (sIgA), were measured as indices of the immune response to determine suitable levels of dietary β-1,3/1,6-glucan supplementation. The results indicated that performance was elevated quadratically with dietary β-1,3/1,6-glucan supplementation. Maximal growth performance and an enhanced immunological response were obtained at a supplemented level of 50 mg/kg.
The yeast cell wall of Saccharomyces cerevisiae is an important source of β-D-glucan, a glucose homopolymer with many functional, nutritional and human health benefits. In the present study, the yeast cell wall fractionation process involving enzymatic treatments (savinase and lipolase enzymes) affected most of the physical and functional characteristics of extracted fractions. Thus, the fractionation process showed that β-D-glucan fraction F4 had significantly higher swelling power and fat binding capacity compared to other fractions (F1, F2 and F3). It also exhibited a viscosity of 652.12 mPa s and a high degree of brightness of extracted β-D-glucan fraction. Moreover, the fractionation process seemed to have an effect on structural and thermal properties of extracted fractions. Overall, results showed that yeast β-D-glucan had good potential for use as a prebiotic ingredient in food, as well as medicinal and pharmaceutical products.
β-Glucan is a cell wall component that is one of the most plentiful cell polysaccharides. Moreover, it has been found to have several beneficial effects on the immune system. In yeast, β-glucan is mainly contained in the yeast cell wall, and thus it is important to produce high levels of cell mass for the mass production of yeast β-glucan. Response surface methodology (RSM) offers a potential means of optimizing process factors and medium components; it has been used to estimate the effects of medium components on cell mass production. In the present study, the optimal concentrations of molasses and corn steep liquor (CSL) in the medium were determined to be 6.4% (v/v) and 17% (v/v). The cell mass predicted by statistical analysis was 9.76 g/L after 20 h of cultivation. In a 2.5-L stirred tank reactor (STR), the cell mass produced in a batch culture was 36.5-39.3 g/L. The maximum cell mass in the fed-batch cultures of Saccharomyces cerevisiae JUL3 was 95.7 g/L using 50% molasses solution and a feed rate of 10 mL/h. The cell mass obtained in the fed-batch culture was 2.4-fold higher than that obtained in the batch culture.
This experiment was conducted to investigate the effects of Lactobacillus acidophilus on performance, carcass characteristics, blood parameters, and intestinal microflora of broiler chicks. The dietary treatments were: basal diet as control 1; basal diet plus 1g. kg -1 of a commercial probiotic Bioplus2; basal diet plus 10 and 20 g kg -1 fermented milk that contained 2×10 8 cfu g -1 Lactobacillus acidophilus. To evaluate the effect of water alone on chick performance, equal volume of water in 20 g fermented milk was added to each kg of the basal diet (control 2). A total of 280 one-day old male broiler chicks were randomly allocated to 5 experimental groups of 4 replicates of 14 chicks each. The chicks were grown to 42 d of age. The result of the experiment indicated that feed intake in chicks fed diet supplemented with commercial probiotic was significantly higher than L. acidophilus probiotic. Weight gain for the chicks fed with the diet that contained 20 g kg -1 fermented milk was higher than the control chicks, in the first 3 weeks. There was no significant difference in feed conversion and weight of organs. The number of Lactobacilli in ileum and colon were higher in L. acidophilus treated birds than the control group and also the number of Coliforms was lower, but the effects were not statistically significant. The levels of blood cholesterol, alanine aminotransferase, aspartate aminotrasferase and alkaline phosphatase were the highest in the control group, but the effect was statistically significant only for ALT measured at 21 d of age.