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Potential of bacterial fermentation as a biosafe method of improving feeds for pigs and poultry

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The use of fermented liquid feeds in monogastric animal nutrition is regarded as one of the biosafe methods of animal production. This paper examines bacterial fermentation of feed substrates for production of fermented liquid feeds for pigs and moist feeds for poultry. Emphasis is placed on the interplay of factors affecting feed fermentation and their relationship to feed quality. The resistance of fermented feeds to enteropathogenic contamination prior to feeding and their potential contribution to African agriculture is highlighted.
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African Journal of Biotechnology Vol. 8 (9), pp. 1758-1767, 4 May, 2009
Available online at http://www.academicjournals.org/AJB
ISSN 1684–5315 © 2009 Academic Journals
Review
Potential of bacterial fermentation as a biosafe method
of improving feeds for pigs and poultry
A. T. Niba1*, J. D. Beal2, A. C. Kudi2 and P. H. Brooks2
1Department of Animal Production, University of Dschang, P. O. Box 447, Dschang, Cameroon.
2Faculty of Science, School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth, Devon PL 4 8AA,
United Kingdom.
Accepted 6 February, 2009
The use of fermented liquid feeds in monogastric animal nutrition is regarded as one of the biosafe
methods of animal production. This paper examines bacterial fermentation of feed substrates for
production of fermented liquid feeds for pigs and moist feeds for poultry. Emphasis is placed on the
interplay of factors affecting feed fermentation and their relationship to feed quality. The resistance of
fermented feeds to enteropathogenic contamination prior to feeding and their potential contribution to
African agriculture is highlighted.
Key words: Fermented liquid feed technology, pigs, poultry.
INTRODUCTION
There is considerable concern over the use of antibiotic
growth promoters (AGPs) in animal production. Their
extensive usage has resulted in the selection for survival
of resistant bacteria species or strains (Doyle, 2001;
Montagne et al., 2003; Khaksefidi and Rahimi, 2005).
This resistance can be transferred to other previously
susceptible bacteria and can be hazardous to both
animal and human health (Montagne et al., 2003).
The use of in-feed AGPs has been banned in the
European Union (Wilkie et al., 2005; Williams et al.,
2005) and there are further attempts to reduce or remove
in-feed AGPs worldwide (Jin et al., 1998; Yegani and
Korver, 2008). This would have significant implications on
gut microbial profiles (Yegani and Korver, 2008) as well
as increase competition between gut microflora and the
host for available nutrients (Dibner and Richards, 2005).
However, there is an active search for alternatives to
AGPs in animal feeding. This includes the use of
probiotics, organic acids, prebiotics, minerals, enzymes,
herbs, phenolic aromatic components and fermented
feeds (FF) (Knarreborg et al., 2002; Reid and Friendship,
2002; Verstegen and Williams, 2002; Dahiya et al., 2006;
Steiner, 2006; Missotten et al., 2007). FF is considered
*Corresponding author. Email: at_niba@hotmail.com or
atniba@yahoo.fr.
as a biosafe method for replacing AGP in pigs
(Knarreborg et al., 2002; Kobashi et al., 2008) and poultry
(e.g. Heres et al., 2003a; Heres et al., 2003b; Heres et
al., 2003d; Niba, 2008). FFs are characterised by high
numbers of lactic acid bacteria (LAB) (approximately 109
cfu/ml of feed) and high concentrations of lactic acid
(>150 mM) (Heres et al., 2003a; Niba, 2008). In chickens,
the organic acid content of fermented feeds has been
reported to improve foregut barrier function against
pathogens by increasing acidity and lowering the pH
(Heres et al., 2003d; Engberg et al., 2006). The
proportion of chlortetracycline-resistant Escherichia coli
strains was significantly reduced in the gut of weaned
piglets fed fermented liquid feed (FLF) (22.2%) compared
with dry feed (88.9%) (Kobashi et al., 2008). This review,
examines the potential of bacterial fermentation of feeds
as a means of improving feeds for pigs and poultry.
Emphasis will be placed on the interplay of factors
affecting feed fermentation and their relationship to feed
quality.
FERMENTED LIQUID FEED TECHNOLOGY
Man has known the use of microbes for preparation of
food products for thousands of years and all over the
world a wide range of fermented foods and beverages
contribute significantly to the diet of many people (Achi,
2005). The use of liquid feeds in animals has created an
opportunity for recycling of liquid co-products from the
human food industry especially in the European pig
industry (Scholten et al., 1999; Brooks et al., 2003a). This
has considerably reduced the need for alternative
methods of disposal of these products, like drying,
disposal to land fill or burning (Scholten et al., 1999).
However, liquid feeds have the potential to serve as
potent reservoirs of enteropathogens unless steps are
taken to prevent their introduction and proliferation during
storage and feeding (Beal et al., 2002). Brooks et al.
(2001) also stated that liquid-feeding systems can easily
become contaminated. They further observed that the
development of computerised liquid-feeding systems
capable of feeding pigs ad libitum has rekindled interest
in the possibility of liquid feeding for weaner pigs. This, in
addition to recent developments in the use of lactic acid
bacteria in the accelerated fermentation of feed
substrates for animal feeding as well as reducing the
possibility of contamination by enteropathogens (Beal et
al., 2002; Beal et al., 2005), has provided a good basis
for improvement in pig nutrition. It is also having much
promise in other farm animal species especially poultry
(Heres et al., 2003b; Skrede et al., 2003; Niba, 2008) and
aquaculture (Refstie et al., 2005). Fermented liquid feed
technology could make important contributions to African
agriculture especially in semi-arid and hot areas (Niba et
al., 2008b). In such areas, ambient temperatures (appro-
ximately 30°C) could support efficient lactic acid
fermentation of feeds (Beal et al., 2002; Niba, 2008).
Furthermore, wet feeding in hot climates has been shown
to improve feed intake and growth rates in poultry
(Forbes, 2003).
According to Beal et al. (2002), lactic acid bacterial
fermentation of feeds provides a feed that has a pH of 3.8
- 4.0 and contains 150 - 250 mmol/L lactic acid. A similar
range of fermented feed pH has been reported by Geary
et al. (1996) (3.8 - 4.2), Christensen et al. (2007) (3.6 -
4.2), Scholten et al. (1999) (3.5 - 4.5) and Moran et al.
(2006) (<3.8). The synergistic effect of a high lactic acid
concentration and low pH is believed to act in concert to
give fermented feeds their antimicrobial activity. This
enables them to withstand contamination by pathogens
like Salmonella spp. (Geary et al., 1996; van Winsen et
al., 2001a; Beal et al., 2002; van Winsen et al., 2002),
Campylobacter spp. (Heres et al., 2004), and coliforms
(Russell et al., 1996).
The mechanism of action of fermented feeds and
fermented co-products in controlling enteropathogens
both in vitro and in vivo has been reviewed extensively
(Brooks et al., 1996; Scholten et al., 1999; Hansen et al.,
2000; van Winsen et al., 2001a; Beal et al., 2002;
Demeckova et al., 2002; Hojberg et al., 2003; Boesen et
al., 2004; van Immerseel et al., 2004; Beal et al., 2005;
Moran et al., 2006). The antimicrobial effects of lactic acid
are believed to be exerted by the ability of the undissociated
acid to gain entry into the cell, disrupt pH homeostasis and
consequently cause nucleic acid and protein damage
(Beal et al., 2002). According to Moran (2001), the low
Niba et al. 1759
pH, dissociation constant (pKa value),and the molar
concentration are factors that determine the inhibitory
activity of lactic and acetic acid in fermented feed. While
inside the cell, the acid dissociates and causes a drop in
pH. This stops enzymatic processes and causes the
proton motive force to collapse. The anion may also
destroy the cell wall resulting in cell death (van Winsen et
al., 2001a; van Winsen et al., 2001b). However, Alakomi
et al. (2000) earlier stated that disruption of the outer
membrane by acids could involve both dissociated and
undissociated forms. As indicated, the likely action on the
outer membrane of Salmonella could be protonation of
anionic components such as carboxyl and phosphate
groups. This consequently weakens the molecular
interactions between outer membrane components thus
increasing its permeability.
In a recent review by Brooks (2008) on fermented
liquid feeds for pigs, increasing feed cost, withdrawal or
reduction of antimicrobial growth promoters (AGP) in
feeds and quality assurance programmes related to
Salmonella in pig meat were given as reasons why
producers should adopt liquid feeding. However, he
indicated that the success of liquid feeding depended on;
i.) Microbial fermentations and selection of LAB capable
of generating lactic acid levels above 100 mmol/L that
can significantly reduce numbers of enteropathogens and
the incidence of Salmonella.
ii.) Batch fermentation of the cereal portion of feeds with
inoculants capable of generating high lactic acid concen-
trations to give more consistent results of fermentation.
iii.) Fermentations that could preserve the feed, improve
the availability of nutrients, reduce the level of anti-
nutrients and have LAB with probiotic properties.
Meanwhile, the three principal components involved in
the fermentation process are the fermenting micro-
organisms, the feed substrate and the enabling
environment for fermentation (Figure 1).
INFLUENCE OF MICRO-ORGANISM AND FEED
SUBSTRATE ON FERMENTATION
The selection of LAB for feed fermentation to meet
desired feed and production objectives has been
highlighted in previous reviews (Brooks et al., 2003b;
Brooks, 2008). The choice of feed substrates to obtain
high numbers of LAB (109 cfu/g feed) and levels organic
acids (>150 mmol/L) or a consistent fermentation product
has also been researched (Canibe et al., 2007a; Niba et
al., 2007; Lyberg et al., 2008; Niba, 2008; Niba et al.,
2008b; Olstorpe et al., 2008) or reviewed (Brooks, 2008).
Fermentation objectives that have influenced the use of
LAB have centred on;
i.) Selection for rapid production of organic acids (mainly
lactic acid) to ensure biosafety (e.g. Missotten et al.,
1760 Afr. J. Biotechnol.
Environment
-Time (hours)
-Temperature
-Moisture content
-Air Composition
Substrate
-Carbohydrates
-Proteins
-Fibres
-Feathers
Micro
-
organism
-LAB
-Yeasts and fungi
Figure 1. Interactions in the fermentation medium. Fermentation conditions influence rate
of fermentation, type of microbe and substrate quantity and quality affects the medium.
2007; Missotten et al., 2008).
ii.) Selection for homolactic fermentation to improve feed
palatability.
iii.) Breakdown of anti-nutrients and increased bioavai-
lability of nutrients (e.g. Bertsch et al., 2003; Brooks et
al., 2003a; Oboh, 2006; Skrede et al., 2007; Lyberg et al.,
2008; Okpako et al., 2008).
A summary of how some of these objectives relate is
shown in Table 1.
The advantages of fermenting feeds can be summarised
from the table as follows;
i.) Reduction in the level of anti-nutrients within the feed.
ii.) Improved bioavailability of minerals (e.g. P, Ca, Mg
and Cu).
iii.) Increase in protein contents (lysine, histidine and
methionine).
iv.) Breakdown of indigestible carbohydrates.
INFLUENCE OF FERMENTATION LENGTH AND
CONDITIONS
The length of steeping feed ingredients, the type of feed
substrates and fermentation conditions influence the
quality of the fermentation product. Steeping time has
been related to its effects on the activity of endogenous
enzymes and the breakdown of anti-nutrients within the
grain. According to Choct et al. (2004a) the effects on
growth and feed intake for weaner pigs resulting from
steeping of feed for 15 h might be related to the release
and activation of endogenous enzymes in the grain. The
activation of these enzyme systems within the grain can
act on cell wall structures in a similar way to exogenous
feed enzymes (Choct et al., 2004b). In reviewing the
effect of steeping in liquid feeding systems, Brooks et al.
(1996) indicated that phytases that were naturally present
in the pericarp of some grains (like cereals) could be
activated by soaking. They also stated that soaking feed
for 8 - 16 h before feeding increased the bioavailability of
phosphorus, calcium, magnesium and copper. In another
study (Lyberg et al., 2008), the phytase activity for a
cereal grain mix of wheat, barley and triticale was 1382
FTU /kg DM and inositol hexaphosphate bound-
phosphorus and total phosphorus were 2.2 and 3.7 g/kg
DM. After fermentation, dietary inositol hexaphosphate
was completely degraded to release phosphorus.
Fermentation of the carbohydrate-rich cereal compo-
nents of the diet separately and combining them with the
protein-rich components just before feeding has some
practical and nutritional advantages (Beal et al., 2002;
Brooks et al., 2003b; Beal et al., 2005; Moran et al.,
2006; Canibe et al., 2007a; Brooks, 2008). Fermenting
the protein rich components produces undesirable end-
products, such as biogenic amines, which could affect the
palatability of fermented liquid feed (Canibe et al.,
2007a). Furthermore, some studies have reported the
degradation of free amino acids added to diets during
fermentation (Handoyo and Morita, 2006; Canibe et al.,
2007b). However, Niven et al. (2006) demonstrated that
the loss of lysine from fermented liquid pig feed was due
to metabolism of lysine by E. coli present in the feed
rather than its utilisation as an energy source by LAB. It
was observed that inoculation of feed with LAB and 50
mmol/L lactic acid at the beginning of fermentation
resulted in lysine levels remaining unaltered after 72 h
fermentation. The addition of acid reduced or eliminated
the E. coli and allowed the lysine to remain intact during
Niba et al. 1761
Table 1. Effect of micro-organisms and feed substrates on feed fermentation.
Fermentation type Substrate pH Lactic acid
or effects
on diet
Acetic acid
or effects
on diet
Ethanol or
effects on
diet
Source
L. plantarum, P.
pentosaceus, Yeasts
Wheat and wheat by-
products
<3.8
4.53
<60
22.21*
<10
22.42*
<10
9.12*
(Moran et al.,
2006)
(Beal et al.,
2005)
Spontaneous
fermentation.
(LAB and Yeasts)
Barley 4.30 34.43* 27.34* 10.74* (Beal et al.,
2005)
Lactobacillus brevis Soybean white flakes 4.8 Elimination of indigestible carbohydrates
and lowered trypsin inhibitor activity (Refstie et al.,
2005)
Lactobacillus sp. (strain
AD2), L. plantarum
(AM4).
Barley and wheat and
barley whole meal flours - Significant reduction in phytic acid, dietary
fibre and -glucans (33.5-18.4 g/kg in
barley), alpha-amylase activity in barley
(Skrede et al.,
2001; Skrede et
al., 2002; Skrede
et al., 2003;
Skrede et al.,
2007)
Lactobacillus acidophilus Sesame seed meal - Phytic acid reduced to below detectable
limits and tannin contents reduced from 20
to 10 g/Kg
(Mukhodhyay
and Ray, 1999)
Lactobacillus plantarum Complete diets of
cereals and soybean
meal
3.6 Reduction in feed dry matter and insoluble
non-starch polysaccharides, increased
viscosity of feed
(Christensen et
al., 2007)
Unspecified in vitro
fermentation
(LAB and yeasts)
Pig grower diet 4.9-5.3 Reduced contents of total and free lysine
(g/kg crude protein, threonine and
methionine
(Canibe et al.,
2007c)
Phytic acid in cereals - Increase in apparent bioavailability of
Phosphorus, Calcium, Magnesium and
Copper
(Brooks et al.,
2001; Brooks,
2008)
LAB fermentation
Fermented fish silage
supplementation in quail
diet
Increase in egg production and quality
(Haugh unit) (Zynudheen et
al., 2008)
Kocuria rosea Poultry feathers
(fermented feather
meal)
- Improved content and availability of amino
acids, lysine 3.46%, histidine 0.94%,
methionine 0.69%.
(Bertsch et al.,
2003; Bertsch
and Coello,
2005)
Aspergillus nigeir and L.
rhamnosus Cassava peel meal - Increase in proteins (24.4%), ash (7.52%),
crude fibre (10.62%) and decrease in
cyanide (7.35 mg/kg)
(Okpako et al.,
2008)
Saccharomyces
cerevisae and
Lactobacillus spp.
Cassava peel meal - Increase in protein content (21.5%) and
decrease in cyanide (6.2 mg/kg), and
phytate (789.7 mg/100 g).
(Oboh, 2006)
g/kg dry matter, *mmol/L, WDG-wet wheat distiller’s grain.
the fermentation process.
The main goal of fermentation is a high lactic acid
concentration (>150 mmol/L) and a low pH (<4.5). Tem-
perature affects fermentation rate and low temperatures
may yield insufficient quantities of fermentation end-
products. According to Carlson and Poulsen (2003) an
increase in fermentation temperature from 10 to 20°C
improved the proportion of total barley phytate that was
degraded during an 8 h fermentation from 48 to 55%.
Corresponding values for total wheat phytate degraded
were 52 and 62%. At 38°C it required 2 h for 72% of the
total phytate to be degraded. Fermentation of a cereal
grain mix at 10°C produced 8.6 gl-1 of lactic acid
compared with 13.6 gl-1 at 20°C (Lyberg et al., 2008). At
low temperatures yeast predominates and produces
ethanol (Brooks, 2008). Insufficient lactic acid concentra-
1762 Afr. J. Biotechnol.
tion with 24 h fermentation cycles which are more
practical on farms may be the case at low temperatures.
Furthermore, spontaneous fermentation of a cereal grain
mix at 10°C required 7 days for the pH to drop to 4.0
compared with 5 days for 15 and 20°C. Prolonged
fermentation also results in considerable variation in
species composition of fermented pig feed (Olstorpe et
al., 2008). Fermentation at 30°C seems ideal as at 35
and 40°C there was no significant effect on lactic
utilisation of feed nutrients like added synthetic lysine by
and acetic acid concentrations (Table 2) while butyric
acid and ethanol concentrations were significantly
increased (Beal et al., 2005). Lactic acid fermentation of
sorghum and maize at 3C produces high levels of lactic
acid (>150 mmol/L) as fermented cereal-base for moist
chicken feed (Niba, 2008; Niba et al., 2008a; Niba et al.,
2008b).
LIQUID TO FEED RATIOS
An important aspect of a successful liquid feeding regime
is the liquid to feed ratio of the diet. This affects the dry
matter content of diet and may also have implications for
the intake and organic acid concentration of the feed.
Research to confirm the ideal dry matter content of liquid
diets is limited (Choct et al., 2004a). In pigs, a wide range
of liquid to feed ratios (3:1, 4:1) (Choct et al., 2004a),
(2:1) (Demeckova et al., 2002; Choct et al., 2004a; Xuan
Dung et al., 2005), (2.5:1)(Russell et al., 1996; Boesen et
al., 2004), (3.5:1) (Geary et al., 1996) have been used. In
chickens, these ratios have been reduced to 1.3:1 (Yasar
and Forbes, 1999) and 1.4:1 (Heres et al., 2003a; Heres
et al., 2003b; Heres et al., 2003c; Heres et al., 2003d;
Heres et al., 2004). With lower liquid to feed ratios,
fermented chicken feeds could be considered as
fermented moist feeds rather than liquid feeds (Niba,
2008). However, the DM concentration of feed has been
shown to have little overall effect on the pattern of
microbial activity (Geary et al., 1996). Meanwhile,
increasing water to feed ratios improved both DM and
energy digestibility of diets for pigs. However, since in
commercial practice with pigs liquid to feed ratios can
vary from 2:1 to 7:1 (Choct et al., 2004a), performance is
likely to be affected by DM intake (Table 3).
CONTROLLED FERMENTATION USING STARTER
CULTURES
Successful fermentation results have also been found to
be dependent on the type of fermentation adopted. A
brief definition of the methods of fermentation is given in
Table 4. Spontaneous (Beal et al., 2005), backslopping
(Moran et al., 2006), inoculated or controlled fermenta-
tions (e. g. Christensen et al., 2007; Canibe et al., 2008)
have been investigated as methods that could be used
for production of fermented liquid feeds. Spontaneous
fermentation has been discouraged (Brooks et al., 2003b;
Brooks, 2008) because in this system yeast, which can
tolerate low pH and a low temperature, can predominate.
Yeast fermentation of starch will result in alcohol and
carbon dioxide production. The production of CO2
represents a loss of feed dry matter and energy value.
Such feeds could be unpalatable due to ‘off’ flavours
resulting in reduced feed intake. Secondly, spontaneous
fermentation may not guarantee a rapid build-up of lactic
acid in the feed, which is necessary for biosafety of the
feed and to limit the pathogens (Niven et al., 2006).
Lastly, since feed ingredients differ in their load of natural
microflora, spontaneous fermentation of the same raw
material at different times results in inconsistent end-
products.
Backslopping has been practiced on many farms (Beal
et al., 2002). The limitations of this method have recently
been highlighted in the review by Brooks (2008). In
addition to these limitations, additions of fresh feed to a
dynamic fermenting medium could have adverse impli-
cations on microbial balance and the ability of the feed to
resist enteropathogens. Temperature shifts during
addition that are outside the optimal range of particular
pathogens could provoke the secretion of cold-shock
proteins (Beal et al., 2002). Such cold shock proteins
could increase pathogen tolerance to lactic acid in feed
fermented at 20°C compared with 30°C.
Controlled fermentation or inoculated fermented liquid
feed would appear preferable for production of fermented
liquid feeds for pigs or fermented moist feeds for chick-
ens because more predictable results could be obtained.
Selection for LAB that produce lactic acid rapidly, with
high 24 h lactic acid (>150 mmol/L) contents (Brooks,
2008), should be the primary objective. The selection of
LAB for other factors, such as probiotic properties is
beyond the scope of this review.
EFFECTS OF FERMENTED FEED ON PERFORMANCE
OF PIGS
In growing pigs, the daily weight gains (kg/day) of FLF
fed groups (0.572) and acidified feed (AF) fed groups
(0.567) were significantly higher (P < 0.05) than pigs on a
dry diet (DF) (0.515) and non-fermented liquid feed
(NFLF) (0.498) (Xuan Dung et al., 2005). Plasma urea
nitrogen was also significantly lower (P < 0.05) in FLF fed
pigs than the dry diet, non-FLF and AF. As observed by
Demeckova (2003), piglets from gilts fed FLF were 300
and 450 g heavier than piglets from the gilts fed NFLF (P
< 0.01) and DF fed gilts (P < 0.001).
Demeckova et al. (2002) reported that faeces from
sows fed FLF feed had significantly (P < 0.001) lower
numbers of coliforms than sows fed NFLF or DF. They
also reported that piglets from sows fed FLF excreted
faeces that were higher in LAB (7.7 vs 7.3 log10 cfu/g, P <
0.01) and lower coliforms (7.5 vs 8.1 log10 cfu/g, P <
0.001) than faeces from piglets of DF-fed dams. Further-
Niba et al. 1763
Table 2. Effect of incubation time and fermentation temperature on feed fermentation.
Incubation
time (h) Temperature
C)
pH Lactic acid or
effects on diet Acetic acid or
effects on diet Ethanol or effects
on diet Source
24 - 3.75 54.5 Yeast population
increases 10- fold Yeast population
increases 10- fold
48 - 3.65 Yeasts population
stabilizes and
coliforms
eliminated mainly
by backslopping
Yeasts population
stabilizes and
coliforms eliminated
mainly by
backslopping
Yeasts population
stabilizes and
coliforms eliminated
mainly by
backslopping
(Moran et al.,
2006)
24 - 4.69 11.68* 17.22* 6.81*
48 - 4.34 31.92* 27.55* 10.62*
72 - 4.21 46.14* 30.75* 12.79*
- 30 4.47 30.16* 16.42* 11.69*
- 35 4.41 25.29* 26.57* 9.78*
- 40 4.36 28.64* 32.89* 8.42*
(Beal et al.,
2005)
48 20 4.2 115* Dvalue (min)-250
72 20 3.9 164* Dvalue (min)-164
96 20 3.8 167* Dvalue (min)-137
48 30 3.8 161* Dvalue (min)-45
72 30 3.8 196* Dvalue (min)-38
96 30 3.8 203* Dvalue (min)-34
(Beal et al.,
2002)
0a 10 - NDb 5.5c
0a 15 - NDb 5.5c
0a 20 - NDb 5.5c
3a 10 - NDb NDc
3a 15 - NDb 5.3c
3a 20 - 2.1b 5.6c
5a 10 - NDb 3.8c
5a 15 - 2.1b 4.6c
5a 20 - 3.1b 4.9c
7a 10 - 2.0b 4.5c
7a 15 - 2.1b 6.2c
7a 20 - 2.1b 5.7c
(Olstorpe et
al., 2008)
0 20 - <3.0±0.00c 5.0±1.27d 3.9±0.00b
6 20 - <3.0±0.00c 6.0±0.12d <3.2±0.21b
24 20 - 8.1±0.75c 7.1±0.56d 3.6±0.16b
48 20 - 9.5±0.34c 6.7±0.87d 3.7±0.95b
0 20 - ND 4.7±0.03 ND
6 20 - ND 4.9±0.16 1.9±0.11
24 20 - ND 5.9±0.42 6.8±0.14
48 20 - 91.2±27.66 20.9±6.21 15.5±1.31
(Canibe et al.,
2007c)
17-19a 10 1.8 10.4 1.2
17-19a 15 1.9 10.4 1.2
17-19a 20 2.2 10.5 1.1
17-19a 10 3.3b 7.2c 2.4d
17-19a 15 3.2b 5.9c 2.3d
17-19a 20 4.8b 7.4c 2.0d
(Lyberg et al.,
2008)
g/kg dry matter, *mmol/L, Dvalue (min)-decimal reduction time (minutes) of Salmonella in fermented feed, adays, byeasts counts (cfu/g feed), cLAB counts
(cfu/g feed), dEnterobacteriaceae counts (cfu/g feed), dmoulds, ND-not detected.
1764 Afr. J. Biotechnol.
Table 3. Effect of liquid to feed ratios of diets on performance.
Liquid to feed ratio Type of operation Remarks Source
2:1, 3:1,4:1 Experimental trial No significant effect on growth and
performance parameters but FCR* of liquid
diets higher (P<0.05) than dry weaner pig diets.
(Choct et al., 2004b)
1.63: 1 to 3.25:1 Experimental trial Digestibility coefficient increase from 0.791 to
0.829 with increase in liquid to feed ratio in
pigs.
(Barber et al., 1991)
1.5:1 to 2.25:1 Experimental trial Feed intake, weight gain and carcass weights
of chickens not significantly affected. (Yalda and Forbes, 1995)
2.1:1 to 5:1 Commercial farms Good results with pigs. (Choct et al., 2004b)
1.5:1 to 3:1 Experimental trial No significant effect on pig performance (Hurst, 2002)
DM 149 to DM 255 Experimental trial Little effect on microbial activity, DM intake,
weight gain or DM FCR of pigs (Geary et al., 1996)
*FCR- feed conversion ratios; Diet dry matter concentrations (g/kg diet).
Table 4. Definitions of types of fermentation.
Type of
fermentation Definition Source
Spontaneous Fermentation through the action of indigenous microflora present in the
feed (Brooks, 2008)
A proportion of a previous fermentation is retained as an inoculum for
fresh feed (Moran et al., 2006).
Backslopping
Consecutive microbial re-inoculation with micro-organisms from the
previous batch (Häggman and Salovaara, 2008)
Inoculated Fermentation resulting from inoculation of feed with selected lactic acid
bacteria (Brooks, 2008)
Controlled Fermentation resulting from inoculation of feed with selected lactic acid
bacteria under controlled environmental conditions (e.g. temperature) (e.g. Beal et al., 2002)
Table 5. Economic analysis of fermented liquid feed for pigs (Nguyen Nhut Xuan Dung et al. 2005).
Parameter DF NFLF AF FLF
Feed cost, VND/kg 3528 3528 5202 3528
Total feed intake, kg 220 213 216 195
Live weight gain, kg 50.9 49.6 55.4 55.0
Feed cost/gain, VND* 15.222 15.182 20.239 12.477
*Vietnamese dong (currency), DF- dry feed, NFLF-non-fermented liquid feed, AF-acidified feed, FLF-
fermented liquid feed.
more, Xuan Dung et al. (2005) (Table 5) has indicated
that feeding FLF to growing pigs is associated with the
lowest feed cost/gain ratios compared with DF, NFLF and
AF for growing-finishing pigs in Vietnam.
EFFECTS OF FERMENTED FEED ON PERFORMANCE
POULTRY
Research on the use of fermented moist feeds on the
performance of chickens is limited. However, some stu-
dies have shown that wet feeding increases the feed
intake and growth rate of chickens (Yalda and Forbes,
1995; Yasar and Forbes, 1999; Mai, 2007). Pre-soaking
of broiler feeds for 12 and 24 h significantly increased dry
matter digestibility and body weight gain in male broilers
(25 - 40 days of age) compared with dry feed (Yalda and
Forbes, 1996). Bacterial fermentation of barley and wheat
whole meal flours with -glucan-degrading LAB has
improved growth and early feed:gain ratio in broiler
chickens (Skrede et al., 2003). A 10% inclusion of
fermented fish waste silage in poultry feed increased egg
quality and production in Japanese quails (Zynudheen et
al., 2008).
Early access to semi-moist diets for day-old chicks
stimulates gastrointestinal (GI) development and pre-
vents dehydration during transport from the hatchery (van
den Brink and van Rhee, 2007). Rapid GI tract
development after hatch is essential for optimisation of
digestive function and underpins efficient growth and
development as well as a full expression of the genetic
potential for production traits (Mitchell and Moreto, 2006;
Mai, 2007). Furthermore, the moistening capacity of the
crop of chicks during the first weeks of life is also
believed to be a limiting factor for the optimal functioning
of the gut when standard solid diets are fed (Mai, 2007).
Yasar and Forbes (1999) attributed the beneficial effects
of wet feeding to decreased viscosity of gut contents,
greater development of the layer of villi in the digestive
segments and reduced crypt cell proliferation in the
crypts of the epithelium. However, more research is
required to provide a better understanding of the
contribution of fermented moist feeds in poultry nutrition.
CONCLUSION
A successful application of fermented liquid feeds in pig
or moist feeds in chicken feeding systems depends on
the ability to select the right balance of LAB, feed
substrates and fermentation conditions capable of pro-
ducing repeatable fermentation results. Meanwhile, the
resistance of such feeds to enteropathogen contamina-
tion during short storage, and their capability to reduce
pathogen colonisation in the gut of pigs and poultry, could
have far-reaching implications for improved food and
environmental safety in warm wet regions of the African
continent.
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The present study was conducted during the month of October-November, 2021 to assess effect of Bekang, naturally fermented soyabean food of Mizoram, on feed efficiency and gut health parameters of broilers as alternative to AGP. Total 240 day-old Vencobb-400 broiler chicks were assigned six dietary treatments dividing into six homogenous groups - standard rations (T1), standard rations with AGP (Bacitracin Methylene Disalicylate) @ 0.5 g kg-1 (T2), standard ration with fermented feed by Lactobacillus acidophilus (106–108 CFU g-1) @ 100 g kg-1 (T3), and standard rations with Bekang @ 50 g kg-1 (T4), 75 g kg-1 (T5) and 100 g kg-1 (T6), respectively. Findings revealed significant effect of Bekang on body weight gain at 42nd day of age, feed conversion ratio and economic return score of broilers. No significant effect was observed on blood biochemical parameters. Histomorphological studies revealed significantly (p<0.05) increased villi length, width, and decreased crypt depth in all prats of small intestine for Bekang supplementation. Caecal bacterial counts revealed increasing trend of lactic acid bacteria and decreased Salmonella and E. coli counts in T4, T5 and T6 compared to T1, T2 and T3. An increasing trend of antibody titre against NDV on 35th day of age indicated improvement of immune status in Bekang supplemented birds. From the findings, it was concluded that Bekang could be a potential alternative to AGP and could be recommended at a level of 50 g to 100 g kg-1 in rations of broiler birds.
... The feeds developed through our research are expected to contain additional beneficial components such as enzymes, and bacteriocins that, both individually and synergistically, enhance farm animals' production performance [7,8]. Fermented feeds play a crucial role in safeguarding the gastrointestinal health of animals, potentially reducing the necessity for antibiotics in compliance with EU regulations [9]. This approach aims to minimize the transmission of antibiotic resistance genes to humans, thereby reducing population exposure to such resistance. ...
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The objective of this study was to evaluate the fermentability of various agricultural raw materials using a novel Liquid State Fermentation (LSF) technique. The formulations were based on protein-rich plant ingredients, such as sunflower, wheat, and rapeseed, addressing the persistent issue of byproducts in the food industry by seeking alternative utilization methods. While the LSF method has been used in pork production, it remains a new technology in the poultry sector. Distiller’s Dried Grains with Solubles (DDGS) and Corn-Gluten Feed (CGF) were chosen based on previous experiments. These mixtures were enhanced by inoculation with various bacterial strains to produce fermented feeds with probiotic properties. The bacteria played a crucial role in the entire fermentation process. The starters included a commercial culture and fresh sweet whey of a semi-hard cheese. Additionally, selected bacterial strains were used based on previous research and literature data. Solaris model bioreactor system were utilized to produce the fermented feeds. This approach aims to promote a healthier gastrointestinal system in farm animals, protecting them against pathogenic bacteria. The fermentation process was designed to generate beneficial molecules such as enzymes, organic acids, and bacteriocins, further supporting the health benefits of the final product. This is significant because such feed can reduce the need for antibiotics in farm animal breeding, aligning with the EU’s stance on minimizing antibiotic usage. Throughout our research, we meticulously monitored the fermentation process, gathering data for a comprehensive comparison. Our analysis focused on changes in pH, the microbiological and hygienic properties of the feed, and the production of organic acids in the fermenting mixtures. The results consistently showed a decrease in pH values after 24 h of fermentation. DDGS with selected strains exhibited the highest LAB counts at 9.89 log10 CFU/cm³, whereas the combination of CGF and whey produced the highest lactic acid concentration at 28.86 mg/ml. These promising results warrant further investigation through animal trials.
... An increase in protein proportions like histidine, lysine, and methionine were also observed. Moreover, the addition of lactic acid bacteria helped in the degradation of indigestible carbohydrates and the rapid fabrication of organic acids mainly lactic acid [44]. Another research was also conducted (using palm kernel cake as substrate) to check the digestion changes in the inhabitants' by comparing the ileum digestibility (of amino acids and crude protein) both in fermented palm kernel cake and unfermented palm kernel cake. ...
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The poultry sector typically accounts for approximately 26% of the total meat production in several countries. However, the poultry sector is grappling nowadays with a rising problem of substandard meat production, owing to the usage of low-quality feed for the chicks. Previous studies have indicated to improve the quality of chick feed, however, researchers are still trying to improve the quality of feed by refining its shelf life and nutritional contents. Fermentation of various agricultural products, other than traditional feed, such as rice husk, palm kernel cake, wheat bran, potato pulp, banana peel, corn seed meal is carried out by using bacterial and fungal cultures to increase the production and quality of chicken feed. Although all these additives have the potential to be used as a replacement for traditional feed, nonetheless the main issue lies in the increased cellulose and fiber content. These constraints are being removed by using bacterial and fungal strains, especially those that are reported to have cellulose digestion and various enzymatic activities. Each strain has its own optimized fermenting conditions, such as solid-state fermentation or submerged fermentation, in which it yields its maximum output, before fermenting any feed with a specific microbe. These optimized conditions and techniques must be monitored in order to get the desired upshot. Therefore, this review article focuses on different substrates fermented by a variety of microbial strains along with their effectiveness and their future prospects. Furthermore, this study aims to suggest an alternative resource, which can be used to meet the poultry needs of the increasing population.
... An argument in favour of the use of rapeseed products is the fact that rapeseed is the most commonly grown oilseed plant in Poland, and fermented products are enriched with bioactive substances (Sońta and Sońta, 2021). The fermentation process increases the population of lactic acid bacteria (LAB), mainly of the genus Lactobacillus, leading to an increase in the amount of lactic acid (Nowakowicz-Dębek et al., 2021;Niba et al., 2009). Intake of fermented feedstuffs has also been observed to cause the death of pathogenic bacteria of the family Enterobacteriaceae . ...
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Understanding digestive functions and the role of microorganisms in the prevention of gastrointestinal and systemic diseases may be a strategy for preventing intestinal dysbiosis during critical periods of animal rearing, strengthening the immune system and reducing herd mortality. The aim of the study was to determine the effect of the addition of fermented rapeseed meal (FRSM) to the diet of rabbits on the composition of the bacterial microbiota of the caecal contents. The experiment was conducted using 40 35-day-old rabbits ( Oryctolagus cuniculus ) assigned to four groups of 10 animals each. Animals in the control group (group C) were fed a standard diet, while the experimental groups received 4% (group E1), 8% (group E2) or 12% (group E3) dried FRSM in place of the previously used soybean meal (SBM). After 120 days, six rabbits (three males and three females), of average size and intended for slaughter, were selected from each group. The contents of the caecum were collected from these animals for metagenomic analysis. The research showed that the microbiome of the caecum of rabbits shows low diversity at higher phylogenetic levels, but is highly diverse at lower levels. The study showed no directly proportional relationship between the various groups of microorganisms inhabiting the digestive tract and the share of fermented rapeseed meal used in the diet. To the best of our knowledge, this is the first study to characterize the microbiome of rabbits fed diets with the inclusion of fermented feed components.
... Researchers have extensively utilized probiotics, such as LAB including E. faecalis, and Bacillus spp. that are known for their proteolytic capabilities and robust stress resistance, to enhance the solubility and intestinal digestibility of SBM during fermentation processes [38][39][40][41]. Despite numerous small-scale laboratory studies on SBM fermentation, there is a scarcity of research emulating large-scale production environments [42][43][44]. ...
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The improvement in the utilization rate and nutritional value of soybean meal (SBM) represents a significant challenge in the feed industry. This study conducted a 50 kg SBM fermentation based on the 300 g small-scale fermentation of SBM in early laboratory research, to explore the combined effects of lactic acid bacteria (LAB) and acid protease on fermentation quality, chemical composition, microbial population, and macromolecular protein degradation during fermentation and aerobic exposure of SBM in simulated actual production. The results demonstrated that the increase in crude protein content and reduction in crude fiber content were considerably more pronounced after fermentation for 30 days (d) and subsequent aerobic exposure, compared to 3 d. It is also noteworthy that the treated group exhibited a greater degree of macromolecular protein degradation relative to the control and 30 d of fermentation relative to 3 d. Furthermore, after 30 d of fermentation, adding LAB and protease significantly inhibited the growth of undesired microbes including coliform bacteria and aerobic bacteria. In the mixed group, the microbial diversity decreased significantly, and Firmicutes replaced Cyanobacteria for bacteria in both groups’ fermentation.
... Also, there is evidence that gut microbiota can alleviate inflammatory response and reduce oxidative stress via the microbiota-gut immunity axis (Brandsma et al., 2015), enhance growth performance and serum immunity via altered composition of cecal microbiota (Li et al., 2020a). Hence, the significant impact of gut microbes on the performance and overall poultry health cannot be overemphasized (Niba et al., 2009). All of these indicate that egg production and egg quality may be modulated by the physiological status and nutrient utilization capacity of the laying hens. ...
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Antinutritional factors in feedstuffs may limit their utilization in livestock production, but fermentation process can be used to improve feed quality; however, studies on fermented soybeans for laying hens remain limited. We investigated the effect of fermented soybean meal (FSBM) at various inclusion levels as a partial replacement for soybean meal (SBM) on egg production, egg quality, amino acid digestibility, gut morphology and microbiota, antioxidant capacity and immune response of young laying hens. A total of 360 Hy-line Brown laying hens aged 18 weeks were selected and divided into 5 groups of 6 replicates each and 12 birds per replicate. The control group received a basal diet while the trial group received the basal diet with FSBM included at 2.5%, 5.0%, 7.5% and 10.0%, respectively, for 12 weeks. Our findings revealed that the nutritional value of FSBM was higher compared to that of SBM in terms of reduced content of trypsin inhibitors and increased contents of crude protein, amino acids and minerals. FSBM enhanced egg production (P < 0.05), feed-to-egg ratio (P < 0.05), and albumen quality (albumen height and Haugh unit) (P < 0.05). Furthermore, FSBM improved apparent fecal amino acid digestibility (P < 0.05), gut morphology (increased villus height, villus width, villus height-to-crypt depth ratio and decreased crypt depth) (P < 0.05), antioxidant capacity (reduced malondialdehyde and increased catalase, total superoxide dismutase, glutathione peroxidase and total antioxidant capacity) (P < 0.05) and immune function (increased concentrations of IgG, IgA, and IgM; increased levels of transforming growth factor beta and Toll-like receptor 2; and reduced levels of interleukin 1β and tumor necrosis factor alpha) (P < 0.05). Further analysis showed that FSBM altered the composition of the gut microbiota favoring beneficial microbes. These findings suggest that probiotic fermentation improved the nutritional value of SBM. The inclusion of FSBM in the diets of laying hens at 2.5% or 5.0% improved amino acid digestibility, gut health, immune function, egg production and egg quality.
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A 28-day feeding trial was conducted to evaluate the growth response of broiler chickens fed rumen digesta filtrate (RDF) fermented earth ball meal at the finisher stage. One kilogram of the digesta was weighed into a bucket, and one litre of water was added, stirred, filtered, and incubated at 23-240 °C for 48 hours. The peeled earth ball roots were divided into three portions and the first portion sundried. In contrast, the second and third portions were packed into two separate capped plastic buckets containing cultured rumen digesta filtrate and a litre of water for the fermentation process at 24°C for 48 hours. The fermented samples were packed into bags, pressed, and sundried. Five broiler finisher diets were formulated, using RDF-fermented earth ball meal to replace maize in the control diet. One hundred and fifty, 28-day-old broiler birds were divided into five groups, each assigned to one of the five diets in a completely randomized design. The result revealed that water and RDF fermentation medium increased (P<0.05) the crude protein content of the earth ball meal from 3.06% to 7.33 and 5.21%, respectively. The gross energy was reduced to 2.28 kcal/g by water fermentation media, while the crude fibre was reduced by RDF media to 9.64%. The ether extract digestibility increased from 54.17% in birds on the control diet to 68.47% in birds fed 10% RDF earth ball meal diet. It was concluded that RDF-fermented earth ball meal could replace maize at 20% in a broiler finisher's diet.
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With the increase in the use of wet feeding systems, there has been a controversy over the optimum water to feed ratio to be used in these systems. Braude et al., (1967) showed that the feed conversion ratio was 20% higher for wet fed pigs compared to dry fed pigs. However, Forbes et al., (1968) found no significant difference in daily gain between wet and dry fed pigs. Gill et al., (1987) conducted an experiment to investigate the effects of different water to feed ratios on the performance of growing pigs provided with an additional water supply. They showed that liveweight gain and feed conversion significantly improved (p < 0.05) as the water to feed ratio of the liquid feed was increased from 2:1 to 3.5:1. The objective of this experiment was to investigate whether water to feed ratio effects digestibility, digestible energy and nitrogen retention.
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Liquid feeding systems develop a microflora that usually becomes dominated by lactic acid bacteria (LAB), and this can be beneficial to the health of the pigs. When levels greater than 100mM lactic acid are generated in liquid feed (LF), this can significantly reduce the numbers of enteropathogens and reduce the incidence of Salmonella. Using fermented co-products from the human food industry or deliberately fermenting LF has the potential to improve gut health and nutrient utilization. The evidence indicates that spontaneous fermentation of LF is unreliable and fails to yield consistently good results. Maintaining a continuous fermentation by retaining a proportion of the feed each day can result in the development of a resident microflora dominated by yeasts. This may compromise both palatability and health and reduce the nutritional value of the feed. Batch fermentation of the cereal portion of the diet using inoculants selected to generate high concentrations of lactic acid has the potential to produce more consistent results. This approach may enable the combination of the preservative and probiotic effects of LAB, while also improving the availability of nutrients in the feed and reducing levels of anti-nutrients and mycotoxins. Accurate assessment of these changes will enable nutritionists to modify raw material specifications and constraints to take advantage of these improvements, and in so doing, improve pig performance and reduce environmental impact.
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Low pH and high lactic acid concentration of fermented feed has been reported to be responsible for the antimicrobial activity of fermented feeds (Brooks et al. , 2001). For example, to prevent the growth of Salmonella spp. in liquid feeds, a threshold lactic acid concentration of 75mM is required (Beal et al ., 2002). Therefore, factors that are likely to affect the production of lactic acid during fermentation will have important implications for the ability of such feeds to withstand colonisation by pathogens. The objective of the present study was to investigate the effect of water quality on the fermentation pattern of sorghum and barley.
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This report will review the history of antibiotic growth promoter (AGP) use in the animal industry, concerns about development of antimicrobial resistance, and response in the European Union and United States to these concerns. A brief description of the history of legislation regarding feed use of antimicrobials in Denmark and the experience of animal producers following the 1998 ban will serve to illustrate the consequences on animal performance and health of withdrawing the approval for this use. The biological basis for antibiotic effects on animal growth efficiency will consider effects on intestinal microbiota and effects on the host animal and will use the germ-free animal to illustrate effects of the conventional microflora. The probability that no single compound will replace all of the functions of antimicrobial growth promoters will be considered, and methods to consolidate and analyze the enlarging database will be discussed.
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The mucosal epithelium of the small intestine constitutes a highly dynamic interface with the external environment through the delivery, digestive processing and absorption of nutrients. The intestinal mucosa is capable of rapid and extensive morphological and functional adaptation in response to evolutionary changes, genetic selection, altered dietary composition or food availability and pathological processes. The function of the intestine and adaptations therein may be studied at the molecular, cellular, organic or whole animal level, employing a variety of in vitro and in vivo techniques. This review addresses the mechanisms mediating adaptations in mucosal structure and function in chickens in response to selection for production traits and in the face of thermal stress and of changes in dietary sodium intake. The data presented draw upon the outputs of studies using membrane vesicles, isolated enterocytes, in vitro sheets and in vivo perfusion preparations. The findings of the different methodologies and approaches are compared and contrasted and their contribution to characterization of digestive and absorptive function in the whole animal is considered. These studies help elucidate the basic mechanisms involved in nutrient absorption from the small and large intestine in the fowl and an understanding of the adaptive potential of the mucosa and the underlying mechanisms may provide the sound scientific basis for nutritional strategies that exploit the physiological adaptations induced by the requirement for improved growth rates or efficiency of production under a wide range of climatic conditions.
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The aim of this work in pigs was to evaluate the effect of fermented liquid food (FLF) and the combination of FLF plus short-term addition of an antibiotic food additive zinc bacitracin (FLF + ZB) compared with fed non-pelleted dry food (NPDF), on microbial metabolism in the gut and the effects on flavour and odour attributes and profiles of pig meat as well as boar odour from entire male and female pigs. At an average start weight of 60 kg, 108 pigs (54 males and 54 females) were equally allocated to three treatments according to pen-replicate, litter and sex. Microbial metabolism in the gut was studied in 24 pigs, eight from each treatment. For sensory profile evaluation (flavour, odour and tenderness) of pork loins from m. longissimus dorsi, 48 pigs (24 entire males and 24 females) were selected. The sensory evaluation of different qualities of flavour and odour as well as tenderness of cooked pork loins (LD) was done by a boar taint (skatole and androstenone) trained taste panel. To evaluate the odour and the flavour, a sensory profile analysis was performed which involved the following attributes: total off-odour/off-flavour, pig, urine, manure, naphthalene, rancid, sweet and sweat in the whole sample including both meat and fat. Giving FLF to pigs significantly changed the microbiota in the gastro-intestinal tract compared with NPDF. In particular, the density of coliform bacteria was reduced in the gastro-intestinal tract of the pigs on FLF. Giving FLF demonstrated no effects on skatole concentration in caecum, colon, blood and backfat and boar odour attributes, whereas administration of FLF + ZB decreased the skatole concentrations and the typical boar odours, pig and manure odour, compared especially with the pigs on NPDF. However, meat from pigs given FLF either with or without zinc bacitracin had smaller but significantly worsened scores for three flavour attributes — pig flavour, rancid flavour and total off-flavour — compared with meat from NPDF pigs and the three flavour attributes were equally affected in both sexes. This seems to point to a significant worsening of meat flavour in pigs given FLF that is independent of sex and boar odour problems (skatole and androstenone).
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To protect consumers from Salmonella infection acquired through the consumption of pork meat, it is necessary to eradicate Salmonella from pork. In order to achieve this, the whole pork production chain should be free from Salmonella, including the pigs at the farm. In epidemiological studies it was concluded that the use of fermented feed plays a significant role in the reduction of Salmonella prevalence in pig farms. However, the mechanism of Salmonella reduction in fermented feed is not known. A controlled feed fermentation was performed using a pure culture of Lactobacillus plantarum. pH reduction, organic acid profiles and bacterial counts were determined. In L plantarum-fermented feed, lactic acid and acetic acid were produced and the pH dropped to a value below 4.0. Antimicrobial products (bacteriocins) could not be detected. The results showed that the produced lactic and acetic acid and the pH in the feed are responsible for Salmonella reduction in fermented feed. L plantarum did not show any other antimicrobial effect on Salmonella.