Effects of antimicrobial feed additives on gut microbiology and blood parameters of weaned piglets
A. Kroismayr, K. Schedle, J. Sehm, M. Pfaffl, C. Plitzner, H. Foissy, T. Ettle, H. Mayer,
Einfluss von antimikrobiell wirksamen Futterzusatzstoffen auf die Mikro- biologie des Verdauungstrakts und Blutparameter von Absetzferkeln 1 Introduction
oils derived from different plants have been tested over theyears to identify their effects on animal performance. Es-
As a result of antibiotic resistance in human pathogenic bac-
sential oil extracts from Oregano, with its chemical main
teria, alternatives for Antibiotic Growth Promoters (AGP)
component carvacrol, has been used as feed additive and
have been developed in recent years. Herbs and botanicals
was investigated in numerous feeding trials where it showed
can be seen as such an alternative (WENK, 2003). Essential
a positive influence on piglets performance (e.g. WALD et
Zusammenfassung
In einem Fütterungsversuch mit 120 Absetzferkeln (8 kg Anfangsgewicht) wurden 2 Futterzusatzstoffe (ätherische Öle aus Oregano, Anis und Zitrusfruchtschalen bzw. Avilamycin) mit einer unbehandelten Kontrollgruppe verglichen. Nach 50 Tagen Verfütterung verbesserten die ätherischen Öle numerisch den Gewichtszuwachs, Futterverzehr und die Futterverwertung (+5 %, +3 % und –1 %), während Avilamycin geringere Effekte aufwies (+1 %, –1 % und –2 %). Am Versuchstag 22 wurden von den 3 Behandlungen jeweils 12 repräsentative Tiere geschlachtet und Blut- proben sowie Chymusproben aus dem Ileum, Caecum und Colon entnommen. Die beiden Futterzusatzstoffe hatten keinen Einfluss auf das Blutbild, reduzierten jedoch die Gehalte an anaeroben und aeroben Keimen, flüchtigen Fett- säuren und Ammoniak im Chymus des Ileums, Caecums und Colons, sowie die Gehalte an biogenen Aminen im Cae- cum. Die pH-Werte und die Gehalte an Trockenmasse (T) in den untersuchten Darmabschnitten blieben unverän- dert mit Ausnahme eines erhöhten T-Gehalts im Colon bei Verfütterung ätherischer Öle. Diese Befunde weisen darauf hin, dass die eingesetzten ätherischen Öle ähnlich dem Avilamycin eine antimikrobielle Aktivität in vivo aufweisen. Schlagworte: Ferkel, phytogene Futterzusatzstoffe, ätherische Öle, Oregano, antimikrobielle Leistungsförderer, Avilamycin.
In a feeding trial involving 120 weaned piglets (8kg initial body weight) two feed additives (essential oils blend deri- ved from oregano, anise and citrus peels vs. Avilamycin) were compared with a negative control group. After 50 days of feeding essential oils improved numerically weight gain, feed intake and feed to gain ratio (+5 %, +3 % and –1 %), whereas Avilamycin effects were less pronounced (+1 %, –1 % and –2 %). At experimental day 22 twelve representa- tive animals from each treatment group were slaughtered and blood samples as well as chyme samples from ileum, cae- cum, and colon were retrieved. Both feed additives did not affect blood analysis but reduced contents of anaerobic and aerobic germs, volatile fatty acids, and ammonia in chyme of ileum, caecum and colon as well as contents of bio- genic amines in caecal chyme. The pH value and dry matter (DM) contents in chyme of the respective intestinal seg- ments remained unchanged except for an increased colonic DM content due to essential oils. These results indicate that essential oils tested in the present study exert an antimicrobial activity in vivo similar to Avilamycin. Key words: Piglets, phytogenic feed additive, essential oils, oregano, antimicrobial growth promoter, avilamycin.
A. Kroismayr, K. Schedle, J. Sehm, M. Pfaffl, C. Plitzner, H. Foissy, T. Ettle, H. Mayer, M. Schreiner and W. Windisch
al., 2001; MOLNAR and BILKEI, 2005). According to RODE-
Table 1: Composition of basal dietsTabelle 1: Zusammensetzung der Basalrationen
HUTSCORD and KLUTH (2002), the reason for this positiveinfluence could be the antimicrobial activity of essential
Feed ingredients (%)
oils, which has been observed in vitro (SIVROPOULOU et al.,
Grower II
In the present study, the effect of addition of a blend of
essential oils derived from oregano, anise and citrus peels to
a weaner piglet diet was compared to the antibiotic growth
promoter Avilamycin. Thereby, the main focus of the ex-
periment was to investigate the mode of action of these feed
additives on gut microbiology in young pigs. Moreover, ef-
fects of the essential oil blend or Avilamycin on blood para-
meters and growth performance were investigated. 2 Material and Methods 2.1 Experimental design, housing and feeding
A total of 120 (65 male and 55 female) newly weaned
piglets (crossbred of Large White × Pietrain, 28 days of age,
mean body weight of 8.2 ± 2.3kg) were used to study the ef-
fects of two feed additives (essential oils and Avilamycin) on
gut parameters and performance. Piglets were distributed
among 40 blocks containing 3 animals according to genet-
ics (litter), sex and initial live weight. The animals of each
block were allotted to three treatments: (1) feed with no ad-
ditions of potentially growth enhancing agents like antibi-
otics, organic acids, probiotics, or excessive contents of Zinc
and Copper (negative control group), (2) feed supplied with
an essential oil blend (essential oils group), and (3) feed sup-
plied with the antimicrobial feed additive Avilamycin (Avil-amycin group).
uct contains 20 g of the essential oils blend. The product was
Over the time course of the experiment, the animals were
added at amounts of 2 g per kg of finished starter and grow-
fed 3 different types of diet formulations, a starter diet er I diets (corresponding to 40 ppm essential oils), and 1 g(day 1 to 7), a grower I diet (day 8 to 22) and a grower II
per kg of finished grower II diet, respectively (corresponding
diet (day 23 to day 50). The composition of these diet for-
to 20 ppm essential oils). Analysis of carvacrol (the major
compound of the essential oil blend) by the Institute of Ap-
For the essential oils group, the botanical product Bio-
plied Botany and Pharmacognosy, University of Veterinary
min® P.E.P. 1000 (Biomin GmbH, Austria) was used. This
Science, Vienna, using the SPME GC technique (ARTHUR
product is permitted in the EC to be fed as feed additive to
and PAWLISZYN, 1990) revealed 9.5 g of the chemical com-
piglets (Reg. (EC) No 1831/2003). It contains essential oils
ponent per kg of the phytogenic feed additive. For the
derived from Oregano (Origanum vulgare), Anise (Pimpinel-
starter, grower I and grower II diets, the respective carvacrol
la anisum) and Citrus peels (Citrus sinensis). Chicory (Ci-
contents were 23.1, 15.1 and 8.5 mg per kg of finished feed
chorium intybus) powder acts as carrier substance. As main
while other feeds contained no or only traces of carvacrol.
active ingredients the product contains the phenolic
For the Avilamycin group, Maxus100 (Elanco Animal
monoterpenes Carvacrol, Thymol, Anethol and the cyclic
Health LTD) was used. It is based on the active ingredient
monoterpene – hydrocarbon Limonen. One kg of the prod-
Avilamycin (Tetracycline) which was permitted for use as
Effects of antimicrobial feed additives on gut microbiology and blood parameters of weaned piglets
AGP in EC during time course of the experiment (year
Sampling and analysis of chyme and blood
2005). Maxus 100 contains 10 % Avilamycin. The product
The 12 selected blocks of animals were professionally
was added to the starter, grower I and grower II diet at
slaughtered in the farms own processing plant after morn-
amounts of 0.4 g per kg (corresponding to 40 ppm Avil-
ing feeding. During bleeding, blood was collected (25 ml
amycin). Analysis of Avilamycin by AGES (Austrian Agency
EDTA tubes; 0.5 ml EDTA per 25 ml whole blood) and
for Health and Food Safety) using agar diffusion method (Eli
Lilly and company, Indianapolis, USA) revealed 42.0, 44.5
From each animal about 100g of chyme from terminal
and 44.5 mg per kg of finished starter, grower I and grower
ileum (at least 15 cm before end of ileum), caecum and
II diet while for other diets the respective contents were below
colon (at the flexura centralis) were collected, immediately
limit of detection or quantification (< 5 mg per kg).
analyzed for pH value (Testo 206, pH meter, Testo AG,
The entire study comprised 3 consecutive experimental
Germany), separated into several 10 ml plastic bottles and
replicates processing 10, 15 and 15 blocks of animals. For
all experimental replicates, piglets were housed in the same
All chyme samples were analysed microbiologically by
air-conditioned room equipped with 3 pens with identical
plate-count technique. One gram of chyme sample was ho-
construction (slatted floor, heated lying area, a height ad-
mogenized in (1/4 strength) Ringer’s solution and decimal-
justable nipple drinker, a cup drinker and a round feeding
ly diluted. Appropriate dilutions were spread plated on se-
hopper). The three treatments (negative control, essential
lective media and incubated for analysis of aerobic/
oils, Avilamycin) were allotted to each one of the 3 pens.
anaerobic total colony count (plate-count agar, 30 °C for
Feed and water was offered ad libitum to the piglets
72 h, aerobic/anaerobic conditions), lactobacilli (MRS
agar, 37 °C, 72 h, anaerobic), lactococci (M17 agar, 37 °C,
On 22nd day of each experimental replicate, 4 blocks of
anaerobic), bifidobacteria (Wilkins-Chalgren agar modi-
animals (2 female and 2 male castrated) with body weights
fied by the addition of acetic acid (1 ml/L) and mupirocin
ranging most close to the median of the entire pens were
(100 mg/L), 72 h, anaerobic), enterococci (kanamycin-
sacrificed in order to obtain samples of gut contents and tis-
esculin-azide agar, 37 °C, 48 h), clostridia (DRCM agar,
sues for further investigations (mean body weight of sacri-
37 °C, 72 h, anaerobic) and enterobacteria (VRB agar,
ficed animals: 13.7±1.7kg). The remaining animals were
maintained in their pens and were fed until day 50 to ob-
For volatile fatty acid (VFA) analysis exactly 500 mg
serve zootechnical performance over the entire production
chyme were mixed with 4 ml aqua destilate, 2 ml internal
standard (oenanthic acid, 0.1 mg/ml) and 300 μl azidiol. This mixture was acidified with 50 μl 6n HCl. After 2 h in-cubation the samples were centrifuged at 9000g for 10 min-
2.2 Sample collection and analysis
utes. After centrifugation the liquid phase was used for gaschromatographic analysis, which was made on a Carlo-Erba
5000 gas-chromatographer (direct injection method) ac-
Animals were weighed individually at the start of the trial and
cording to Restek applications note # 591155B (Restek cor-
on trial days 21 and 50. Feed intake of pens was evaluated
daily during the first 21 trial days (representing all animals),
Biogenic amines were analyzed with HPLC according to
and then at day 22, 29, 36, 43 and 50 (representing animals
the method described by MAYER et al. (2006).
not sacrificed). Feed to gain ratio was calculated for days 0 to
Ammonia contents of chyme samples were analyzed pho-
21 (all animals) and days 0 to 50 (animals not sacrificed) from
tometrically with an enzymatic test kit (Boehringer/R-Bio-
respective pen means of growth data and feed intake.
Frozen blood samples were sent to a commercial veteri-
nary laboratory (Vetmed Labor, Ludwigsburg, Germany)
Feed samples of all diets were collected at the beginning of
and a blood screening was made. A small blood analysis
each new feeding period and were analyzed for their con-
(leucocytes, erythrocytes, hemoglobin, hematocrit, mean
tents of dry matter, crude protein, crude fat, crude fibre,
cell volume (MCV), hemoglobin per erythrocyte (HBE),
starch, sugar and crude ash according to standard methods
mean corpuscular hemoglobin concentration (MCHC),
thrombocytes) and a differential blood analysis (basophil
A. Kroismayr, K. Schedle, J. Sehm, M. Pfaffl, C. Plitzner, H. Foissy, T. Ettle, H. Mayer, M. Schreiner and W. Windisch
granulocytes, eosinophil granulocytes, neutrophil granulo-
slightly reduced feed to gain ratios compared to the nega-
cytes, lymphocytes, monocytes) was conducted with an au-
tive control (for the 50 day period: +5 %, +3 % and –1 %).
For the Avilamycin group, the numerical differences weresmaller and less consistent (+1 %, –1 % and –2 %). How-ever, none of these figures reached statistical evidence. 2.3 Statistics
One animal of trial group 3 (Avilamycin) had to be exclud-
Microbial investigations showed that colony counts were
ed from statistical analysis because of irregular growth data.
influenced by both feed additives (Table 3). Compared
The data was submitted to two-way analysis of variance
to the negative control, both feed additives decreased
with the dietary treatment (1, 2, 3) and animal block (1, 2,
(p < 0.05) anaerobic germ count in the ileal chyme and the
3 … 40) as factor levels. For feed intake and feed conver-
same tendency was found for aerobic bacteria. In caecum,
sion ratio the pen was used as statistical factor instead of an-
counts of aerobic and anaerobic bacteria, lactococci and
imal block. The following tables present the mean values of
clostridia were lower (p < 0.05) in the essential oil group
the animal groups and the pooled standard error (S.E.) as
than in the Avialmycin group, whereas negative control had
retrieved from the analysis of variance. The mean values
intermediate counts. In caecum, contents of bifidobacteria
were tested by a multiple comparison procedure (Student-
were decreased in the Avilamycin group (p < 0.05) com-
Newman-Keuls test). Significant differences among means
pared to the other groups and counts of clostridia in chyme
(p < 0.05) are marked by superscript letters a,b,c. Values
of essential oil group was lower (p < 0.05) compared to the
showing a tendency to differ (p < 0.1) are marked by super-
script letters in parenthesis (a), (ab), (b). Additionally, the
Contents of volatile fatty acids (VFA) in the ileal chyme
means of the essential oils group and the Avilamycin group
were not systematically influenced by either feed additives
were compared via a linear contrast with the means of the
(Table 4). On the contrary, in ceacum both feed additives
negative control group. Significant differences (p < 0.05) are
decreased (p < 0.05) acetic acid concentration and the same
tendency was observed in colonic chyme. Essential oils andAvilamycin in the diets led to numerically decreased con-tents of summarized VFA in caecum (–9 %; –12 %) and
3 Results
Biogenic amine concentrations in ileal and colonic chyme
were not influenced by either feed additive (Table 5). In
As shown in Table 2, animals supplied with essential oils
ceacum, essential oils and Avilamycin led to decreased (p <
showed a numerically higher weight gain, feed intake and
0.05) contents of Methylamin, Isopropylamin and Sper-
Table 2: Zootechnical performanceTabelle 2: Zootechnische Leistungen
Neg. control Ess. Oils Avilamycin
Effects of antimicrobial feed additives on gut microbiology and blood parameters of weaned piglets
Table 3: Colony counts in the chyme of ileum, caecum and colonTabelle 3: Keimzahlen im Ileum-, Caecum- und Colon-Chymus
Neg. control Ess. Oils Avilamycin Colony counts in the chyme of ileum (log[CFU]1)per g fresh matter)Aerobic bacteria, sum (12/12/12)2)
Colony counts in the chyme of caecum (log[CFU]1)per g fresh matter)Aerobic bacteria, sum (12/12/12)
Colony counts in the chyme of colon (log[CFU]1)per g fresh matter)Aerobic bacteria, sum (12/12/12)
(xx/yy/zz) = number of samples with detectable colony counts (xx: Neg. Contr, yy: Ess. Oils, zz: Avilamycin)
Means without similar superscripts differ significantly (p < 0.05)
(a) (b) Means without similar superscripts show tendency to differ significantly (p < 0.10)*
Means are statistically different from respective negative control level (p < 0.05)
midin. Concentrations of Agmatin, Dimethylamin and
lymphocytes 51 %; hemoglobin 10 g/dL; erythrocytes
Tyramin in chyme of the three investigated gut areas were
6T/L; HBE 17 p/g; MCV 60 fl; MCHC 28 g/dL; neu-
trophil granulocytes 44 %; thrombocytes 320 g/L.
Dry matter (DM) contents of ileal and caecal chyme were
similar for all treatments, but DM of colonic chyme was in-creased (p < 0.05) in the essential oil group compared to
4 Discussion
other groups (Table 6). Ammonia contents of chyme werenumerically decreased in the essential oils group (ileum:
This study aimed to investigate gut parameters thought to
–18 %; ceacum –24 %) and in the Avilamycin group
be influenced by feed additives with antimicrobial activity
(ileum: –7 %; caecum: –17 %; colon: –17 %). However,
like AGP (Antibiotic Growth Promoters), organic acids or
these differences were statistically not significant. pH of
phytobiotic substances. Antibiotic activity of feed additives
chyme was not influenced by treatment.
may lead to less growth of undesired microbes in the intes-tine, less exposure to microbial products stressing the or-
ganism, and a higher absorption of nutrients, all of these
Blood analysis did not differ between the 3 trial groups. The
factors resulting in an improved growth performance of
following average contents of blood parameters were found
piglets kept under common housing conditions (GREIFE
in the blood samples: leukocytes 17 g/L; hematocrit 37 %;
and BERSCHAUER, 1988). Following this paradigm it was
A. Kroismayr, K. Schedle, J. Sehm, M. Pfaffl, C. Plitzner, H. Foissy, T. Ettle, H. Mayer, M. Schreiner and W. Windisch
Table 4: Contents of volatile fatty acids in the chyme of ileum, caecum and colonTabelle 4: Flüchtige Fettsäuren (VFA) im Chymus von Ileum, Caecum und Colon
Neg. control Ess. Oils Avilamycin VFA in chyme of ileum (mmol/kg fresh matter)Acetic acid
VFA in chyme of caecum (mmol/kg fresh matter)Acetic acid
VFA in chyme of colon (mmol/kg fresh matter)Acetic acid
Means without similar superscripts differ significantly (p < 0.05)
(a) (b) Means without similar superscripts show tendency to differ significantly (p < 0.10)*
Means are statistically different from respective negative control level (p < 0.05)
not the primary ambition of this study to get performance
swine intestinal tract. The inhibitory action of aromatic
data. It was more important to take a view at parameters of
compounds like carvacrol is related to the hydrophobicity
gut physiology associated with microbial activity, which
and on their partition in the cytoplasmic microbial mem-
may possibly explain the growth promoting effect of essen-
branes (LANCIOTTI et al., 2003). Such lipophilic com-
tial oils. Therefore we investigated a blend of essential oils
pounds posses a high affinity for cell membranes and they
derived from oregano, anise and citrus peels in comparison
affect lipid ordering and the bilayer stability resulting in a
In vitro trials showed that numerous essential oils or their
In the present study essential oils as well as Avilamycin de-
main active compounds exert antimicrobial activity. Espe-
creased contents of aerobic and anaerobic bacteria in the
cially oregano and anis essential oils are well known for such
ileal chyme. This is in accordance to the antimicrobial ac-
an antimicrobial activity against various bacterial strains
tivity of the both feed additives. Moreover, it seemed that
(SIVROPOULOU et al., 1996; HAMMER et al., 1999; WENK,
antimicrobial activity of the essential oils product led to
2003; SI et al., 2006). Similarly, NAMKUNG et al. (2004) re-
lower contents of aerobic and anaerobic bacteria, lactococ-
port that a herbal extract containing oregano and thyme ap-
ci and clostridia in the caecum. Surprisingly the feed an-
pears to reduce proliferation of coliformic bacteria.
tibiotic (Avilamycin) had no effect on that microbiota in
The main active compound of the essential oils blend
this gut area. The reductive effect of the essential oils prod-
used in the present study was the phenolic substance car-
uct on clostridia was also found in the colon whereas Avil-
vacrol. This lipophilic substance was found to be a very ef-
amycin led to decreased contents of bifidobacteria. But in
ficient antimicrobial compound in vitro (BEN ARFA et al.,
another study testing oregano essential oils as feed additives
2006). Similarly, SI et al. (2006) report carvacrol to have a
to piglets no influence on gut microflora could be observed
high antimicrobial potential against pathogenic bacteria in
(GÖSSLING, 2001). It may therefore be hypothesized that
Effects of antimicrobial feed additives on gut microbiology and blood parameters of weaned piglets
Table 5: Contents of biogenic amines in chyme of ileum, caecum and colonTabelle 5: Biogene Amine im Chymus von Ileum, Caecum und Colon
Neg. control Ess. Oils Avilamycin Biogenic amines in chyme of ileum (mg/kg fresh matter)Colamin (12/12/12)1)
Biogenic amines in chyme of caecum (mg/kg fresh matter)Colamin (12/12/12)
Biogenic amines in chyme of colon (mg/kg fresh matter)Colamin (12/12/12)
(xx/yy/zz)= number of samples with detectable biogenic amines (xx: Neg. Contr; yy: Ess. Oils; zz: Avilamycin)
a b Means within row without similar superscripts differ significantly (p < 0.05)*
Means within row are statistically different from respective control level (p < 0.05)
Table 6: Dry matter, ammonia contents and pH values in chyme of ileum, caecum and colonTabelle 6: Trockenmasse, Ammoniakgehalte und pH-Werte im Chymus von Ileum, Caecum und Colon
Neg. control Ess. Oils Avilamycin
a b Means within row without similar superscripts differ significantly (p < 0.05)
A. Kroismayr, K. Schedle, J. Sehm, M. Pfaffl, C. Plitzner, H. Foissy, T. Ettle, H. Mayer, M. Schreiner and W. Windisch
sensitivity of microbial colony counts based on plate-count
Ammonia contents and pH values in chyme were not in-
techniques is limited when used as parameter of antimicro-
fluenced by one of the both feed supplements tested in the
bial activity of essential oils or APG in vivo. Nevertheless,
present study. But it is interesting that in the group fed es-
the present study clearly demonstrates that essential oils
sential oils, ammonia contents were numerically lower ex-
may decrease bacterial contents in the investigated gut
cept in the colon. Ammonia in the gastrointestinal tract is
areas, especially in the terminal ileum.
often considered as putrefactive product released by bacte-
The volatile fatty acids (VFA) are produced in the gas-
ria like E. coli (SHIM et al., 2005). Therefore, decreased
trointestinal tract by microbial fermentation of carbohy-
ammonia contents are a sign for lower bacterial activity.
drates and endogenous substrates (IMOTO and NAMIOKA,
Consequently the numerical reduction of Ammonia con-
1978; BERGMAN, 1990). In the present study, VFA contents
centration in the essential oil group is in accordance to the
of chyme were generally in accordance with literature
concept of an antimicrobial activity of the essential oil
(MÖLLER, 2001). The essential oils additive and Avilamycin
decreased contents of acetic acid in the caecum (p < 0.05)
Blood analysis ranged within normal values without
and the colon (p < 0.1), and, numerically the sum of all in-
being changed by Avilamycin or essential oils, respectively.
vestigated VFA. MÖLLER (2001) tested an oregano essential
This is in accordance to data of CHO et al. (2006) indicat-
oil in weaner piglets and reports that contents of VFA ing that essential oils do not directly affect blood analysis. (C – C ) in the gut were numerically decreased in the small
In total, normal blood analysis values indicated an overall
intestine. MANZANILLA et al. (2004) showed that the pro-
proper health status of animals independent of the intesti-
portion of acetate to butyrate was increased in the caecum
nal effects of the feed additives tested in the present study.
and colon of early weaned pigs when adding an oregano
The changes in chyme parameters observed in the present
based essential oil product to the piglets’ diets. In total, es-
study give rise to the hypothesis that the mode of action of
sential oils clearly change microbial VFA production in the
the essential oil blend is similar to that of the feed antibiot-
piglets’ intestine. According to the similarity of the effects
ic Avilamycin. Bacterial activity in the gut was reduced by
on VFA observed in the present study for both feed addi-
both additives as bacterial counts as well as contents of
tives, the reduced production of VFA due to the essential
volatile fatty acids, biogenic amines, and ammonia were re-
oils may be interpreted as a result of an antimicrobial activ-
duced. This may explain the positive effects of essential oils
on piglets’ performance reported in literature. RODE-
Biogenic amines in chyme are produced by intestinal mi-
HUTSCORD and KLUTH (2002) summarized the effects of
crobes via decarboxylation of amino acids. This can stress di-
numerous essential oils on weaner piglets and mentioned
gestion and may have negative effects on performance.
that growth rate and feed to gain ratio can be improved on
Moreover, the formation of biogenic amines has toxicologi-
average by 2 % in each case. WALD et al. (2001) reported
cal impacts in the gut. These negative effects can be over-
even higher growth rates and feed to gain ratios by 7 % due
come by feeding nutritional antibacterials (DIERICK et al.,
to oregano essential oils in piglet diets. More recent data
1986). Also the use of organic acids as feed additives is
from MOLNAR and BILKEI (2005) confirm the growth pro-
known to reduce the intestinal load of biogenic amines
moting effect of oregano feed supplement in piglets. Fur-
(ECKEL et al., 1992). In the present study there was no sta-
thermore, WENK (2003) mentions that herbs, spices and es-
tistically significant influence of either feed additive on pro-
sential oils can stimulate feed intake of animals. In the
duction of biogenic amines in the ileum and colon but there
present study, animals supplied with the essential oils addi-
were lower contents of some biogenic amines in the caecum
tive tended to consume more feed. Daily weight gains were
chyme. Moreover, summarized contents of all investigated
numerically highest in the essential oils group and feed to
biogenic amines were numerically lower in both groups with
gain ratios were slightly decreased by both feed additives. In
feed additives. In total, the influence of the tested essential
another study testing the same feed additive as in the pre-
oils on production of biogenic amines in the three investi-
sent experiment, the growth promoting effect of the essen-
gated gut sequences was very similar to the investigated AGP
tial oils revealed to be statistically significant (STEINER et al.,
(Avilamycin). Given that biogenic amines are products of
the gut microflora, in analogy to argumentation of reduced
In summary, we conclude that antimicrobial activity of
VFA concentrations these results give further rise to the ex-
essential oils used as feed additives to weaner piglets is one
istence of an antimicrobial activity of essential oils in vivo.
of the major mode of action explaining the well established
Effects of antimicrobial feed additives on gut microbiology and blood parameters of weaned piglets
growth promoting effect of these substances. Further evi-
GREIFE, H. A. and F. BERSCHAUER (1988): Übersichten zur
dence of this hypothesis is provided by more detailed in-
vestigations on nutrient digestibility (ZITTERL-EGLSEER et
HAMMER, K. A., C. F. CARSON and T. V. RILEY (1999): An-
al. 2007) as well as on histological and molecular biological
timicrobial activity of essential oils and other plant ex-
parameters of gut tissues (KROISMAYR et al. 2007).
tracts. J. Appl. Microbiol. 86 (6), 985–990.
IMOTO, S. and S. NAMIOKA (1978): VFA production in the
pig large intestine. J. Anim. Sci. 47 (2), 467–476. 5 Acknowledgement
IMOTO, S. and S. NAMIOKA (1978): VFA Metabolism in the
pig. J. Anim. Sci. 47 (2), 479–487.
The authors whish to thank Biomin GmbH, Herzogen-
KROISMAYR, A., J. SEHM, M. W. PFAFFL, K. SCHEDLE, C.
burg, Austria, for supporting this study.
PLITZNER and W. WINDISCH (2008): Effects of avil-amycin and essential oils on mRNA expression of apop-totic and inflammatory markers and gut morphology of
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Palliatieve zorg Richtlijnen voor de praktijk Schema ter beoordeling voor klankbordgroep somatisch vs. Psychiatrisch Inhoudsopgave: 1. Amyotrofische Integrale behandeling: voorlichting, communicatie, continuitiet van zorg . 7 Behandeling van oorzaak: . 7 Niet medicamenteuze symptomatische behandeling . 7 Medicamenteus . 7 Beleid bij reversibele dwarslaesie . 10 Beleid bij irreversibe
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