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Performance, diarrhea incidence, and occurrence of Escherichia coli virulence genes during long-term administration of a probiotic Enterococcus faecium strain to sows and piglets¹

Institute of Animal Nutrition, Faculty of Veterinary Medicine, Free University Berlin, 14195 Germany

	Abstract

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As part of an interdisciplinary research project, the performance response of sows and their litters to the probiotic strain Enterococcus faecium NCIMB 10415, as well as some health characteristics of the piglets, were studied. Gestating sows (n = 26) were randomly allotted into 2 groups. The probiotic was administered by dietary supplementation to 1 group of sows and their respective litters (probiotic group), whereas the second group (control group) received no probiotic supplementation. The duration of the treatment was nearly 17 wk for sows (d 90 ante partum until d 28 postpartum) and 6 wk for piglets (d 15 to 56). Body weight and feed consumption were recorded weekly. The frequency of 4 toxin and 5 adhesion genes of putative pathogenic Escherichia coli was monitored weekly (d 7 to 35) by multiplex PCR assays, and fecal consistency of weaned piglets was studied daily. Probiotic treatment of lactating sows led to an overall pre-weaning mortality of 16.2% compared with 22.3% in the control group (P = 0.44). Animal losses during the first 3 d of the suckling period were decreased in the probiotic group (P = 0.09). For piglets (n = 153), which were weaned at 28 d, there were no overall treatment differences in BW gain, feed intake, or feed efficiency. Probiotic supplementation, however, led to nearly a 40% reduction (P = 0.012). The actual percentage of piglets with postweaning diarrhea in the probiotic group was 21% compared with 38% in the control group (P = 0.05). The study on virulence factors of dominant fecal E. coli isolates revealed a high diversity with varying frequency and distribution of each single pathogenicity gene. The 440 isolates carried 29 different pathogenicity gene combinations as well as each of the 9 pathogenicity genes alone. Altogether, isolates with more than 2 pathogenicity genes were quite rare ( 10%), and up until d 28 isolates without any pathogenicity gene occurred most frequently. Depending on the time of sampling, one-third or more of all isolates contained est2 or est1b as single gene or in combination with other pathogenicity genes.

Key Words: Enterococcus faecium NCIMB 10415 • diarrhea • pathogenicity genes • performance • pig • probiotics

	INTRODUCTION

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A variety of substances are administered as feed additives to farm animals to improve a range of features relevant for animal production (Göransson, 2001; EC No. 1831/2003/2003; Wenk, 2003). Many feed additives target intestinal bacteria because the development of the complex gastrointestinal system holds the key to productivity in all domestic livestock (Jensen, 1998). Probiotics claim beneficial effects by "improving the intestinal microbial balance" (Fuller, 1989). This vague definition implies that the modes of action of probiotics are as yet not well characterized nor fully understood (Tannock, 1999; Simmering and Blaut, 2001; Abbott, 2004).

Most consistent are reports on decreased occurrence and severity of diarrhea in piglets (Underdahl, 1983; Männer and Spieler, 1997; Kyriakis et al., 1999). This can be viewed as an indication that the intestinal microbiota of probiotic fed piglets is indeed less "out of balance," i.e., the adaptability of the gut ecosystem is not challenged beyond its functional abilities. Optimizing the gastrointestinal ecosystem, especially during the stressful weaning transition period with its combination of environmental, social, and nutritional adjustments seems of utmost importance to prevent diarrhea and its consequences for piglet health and performance.

Studies indicate a favorable impact of probiotics if applied early in life (Jadamus et al., 2001). Therefore, the objective of this study was to investigate the effectiveness of a long-term application of the EU-authorized probiotic strain Enterococcus faecium NCIMB 10415 on performance and health characteristics of sows and their offspring. The animal trial in this study was the basis for a multidisciplinary research group (German Research Foundation, Research Unit 438) enabling an integrative analysis of the modes of action of probiotics in swine (Macha et al., 2004; Taras et al., 2004; Nordhoff et al., 2005; Pollmann et al., 2005; Scharek et al., 2005).

	MATERIALS AND METHODS

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The study was approved by the local animal welfare committee of the Federal Ministry of Consumer Protection, Food and Agriculture (No. G0037/02).

Animals and Housing
Landrace x Duroc sows (n = 26) and their litters were used. Gestating sows were housed without straw bedding on a concrete floor in an environmentally regulated building in groups of 3 to 4 sows. Sows were moved to the farrowing facilities 10 d before the expected parturition, where they were housed individually on straw bedding, together with their litters, until weaning. To promote intake of prestarter feed, litter size within each treatment group was adjusted to meet an exclusion criterion of at least 9 but not more than 15 living piglets at 24 h after birth.

Piglets were weaned after d 28 of age and reared together with their littermates as pairs or triplets in pens (2 m²/pen) that were segregated from each other by continuous partitions up to a height of 0.4 m topped with an additional 0.4 m of metal grid. Sows and piglets of both treatment groups were strictly separated in housing facilities with identical constructional and environmental conditions, which were spatially discrete from each other (i.e., the distance between the facilities of treatment groups for sows and weaned piglets was at least 120 and 15 m, respectively).

Each animal facility was equipped with its own maintenance tools, disinfection spray, and floormats soaked in disinfectant. Direct contact between keepers and pigs was restricted to the minimum necessary to prevent transmission of microbiota between treatment groups. The absence of the probiotic strain in animals of the control group was confirmed in random fecal samples of sows and piglets as well as intestinal contents of piglets (Macha et al., 2004).

From a total of 5 randomly chosen litters of each treatment group, 1 piglet per litter was selected at random, each at the end of d 14, 28, 35, and 56, respectively (i.e., 20 piglets per treatment), to be killed for additional microbiological, immunological, physiological, and histological investigations of the intestinal tract (data not shown; partially published by Macha et al., 2004; Taras et al., 2004; Nordhoff et al., 2005; Pollmann et al., 2005; Scharek et al., 2005). Because monitoring of the microbial composition in feces and digesta was one of the main aims of the study, the application of prophylactic and therapeutic antibiotics to gestating and lactating sows as well as piglets was prohibited during and at least 3 mo before the study. Animals (or in the case of nursing piglets, the whole litter) that needed medication, which might have had the potential to alter the intestinal microbiota, were excluded from the trial.

The lighting program was 16 h light and 8 h of darkness. The room temperature and relative humidity were adjusted to 21.5°C and 65.0%, respectively.

Diets
Two diets differing only in probiotic supplementation were used for each respective age group and reproduction stage. Sows were randomly assigned to 1 of 2 dietary treatment groups, which were then also implemented on their respective litters. The basal diets for the sows were composed mainly of barley and wheat, and the basal diets for piglets were based on wheat and soybean meal (Table 1). All sow diets were pelleted, but piglet diets were fed in mash form. Gestating sows and lactating sows were fed restrictively according to their body mass and litter size, respectively. Piglets had ad libitum access to prestarter feed from d 15 to 28 and to starter feed from d 29 to 56 of age. Sows and piglets had ad libitum access to water.

Using colony hybridization of Enterococcus spp. grown on Slanetz-Bartley agar (Oxoid, Basingstoke, Hamshire, UK) in combination with a strain-specific oligonucleotide probe as described (Macha et al., 2004), the mean concentration (± SEM) of the supplemented E. faecium NCIMB 10415 in the feed for gestating sows, lactating sows, nursed piglets, and weaned piglets was 1.6 (± 0.5) x 10⁶, 1.2 (± 0.3) x 10⁶, 1.7 (± 0.8) x 10⁵, and 2.0 (± 0.4) x 10⁵ viable cells/g of feed, respectively. The probiotic strain was not detectable in control feed (Macha et al., 2004), and other Enterococcus strains reached only low colony counts of less than 1,000 cfu/g. The applied diets were formulated to fulfill NRC recommendations (NRC, 1998) using a commercial optimization software (Hybrimin version 1.6.5, Hess. Oldendorf, Germany). All diets were analyzed for the nutrient contents (DM, CP, crude fiber, crude ash, Ca, and P) according to recommendations of the Verband Deutscher Landwirt-schaftlicher Untersuchungs- und Forschungsanstalten (VDLUFA, i.e., the Association of German Agricultural Tests and Research Institutions; Naumann and Bassler, 1993).

Performance
The number of live-born piglets, weight loss of sows during lactation, litter weight at birth and weaning, as well as piglet mortality until weaning, served as performance indicators for the sows. Body weight of piglets was documented in weekly intervals over an 8-wk period. Weekly feed intake per pen of weaned piglets was measured as weight of feed disappearance minus weight of spilled or wasted feed. From these data, BW gain per pen and feed efficiency per pen were calculated. Fecal consistency was measured daily using a macroscopic score from 1 to 4 (firm to liquid). Diarrhea was defined as liquid consistency (score 4) over a minimum of 2 consecutive days (Männer and Spieler, 1997). The number of weaned piglets with diarrhea and its duration were recorded. The incidence of diarrhea (%) was calculated as a percentage of the number of newly affected piglets during the first 4 wk after weaning divided by the total number of weaned piglets.

Detection of Porcine Pathogenic Escherichia coli Isolates
Four litters in the probiotic group and 5 litters in the control group were selected at random to investigate the gene frequency of pathogenic E. coli isolates. From each litter fecal samples of 1 at random selected healthy piglet (see Table 4) were taken immediately after defecation 1 wk after birth (d 7), directly before the first solid feed was offered (d 14), 3 wk after birth (d 21), just before weaning (d 28), and 1 wk after weaning (d 35). Fecal samples were subject to a series of 10-fold dilutions in sterile PBS and incubated in duplicate on selective DEV-Endo-Agar at 37°C for 24 h. Lactose-positive colonies with typical green-metallic appearing surface were enumerated as cfu of putative E. coli (in the following referred to as E. coli) on those agar plates. From those plates, dilutions with a maximum of 50 colonies were selected, 10 lactose-positive colonies per sample were picked off at random (i.e., a total of 440 colonies), and supernatants of the heated cell suspensions used as PCR templates.

Touchdown-PCR was performed using a T-1 Thermocylcler (Biometra, Göttingen, Germany) running the following program: 900 s at 95°C for activation of polymerase, 10 cycles of 30 s at 94°C, 90 s at 60°C (– 0.5°C/cycle), 90 s at 72°C followed by 30 cycles 30 s at 94°C, 90 s at 55°C, 90 s at 72°C, final elongation 600 s at 72°C, then the temperature maintained at 4°C. The DNA was separated on a 2.5% agarose gel containing 10 µL of SybrGreen nucleic acid gel stain (BioWhittaker Molecular Applications, Rockland, ME) per 100 mL of agarose gel. The gel pattern was documented on a UV-table using a CCD camera (Sensicam QE, PCO AG, Kehlheim, Germany) coupled with a UV-filter module (Raytest, Stranbenhardt, Germany) and compared with an internal standard (E. coli O138:K81, E. coli O147:K89:K88, E. coli CS2011, E. coli O9:K35:K99, and E. coli DSM 2840 as described by Gobel, 2003).

Statistical Analyses
All statistical analyses were performed using SPSS (SPSS, Inc., Chicago, IL). For performance of sow BW, fecal consistency, and diarrhea, the individual animal was the experimental unit. For frequency of pathogenicity genes, ADG, ADFI, and G:F, each pen was an experimental unit. The normality of the data was checked using the nonparametric Kolmogorov-Smirnov test with the Lilliefors correction. Before analysis for treatment differences, the data were subjected to Levene’s test for homogeneity of variances. The Mann-Whitney-U-test was used for comparison of all performance data from sows and piglets as well as the duration of periods with reduced feces consistency. The ² procedure was used to compare the incidence of diarrhea and the frequency of liquid feces between treatment groups. Differences were considered significant at an alpha level of P < 0.05. The occurrence of E. coli isolates with pathogenicity genes was too infrequent to allow for statistical analyses; hence, tabular values of animals testing positive for isolates with pathogenicity genes as well as their frequencies are presented.

	RESULTS

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Performance
The performance characteristics of 10 sows in each treatment group are given in Table 2. Those sows had comparable initial BW (190.7 ± 8.8 kg vs. 198.5 ± 6.9 kg, P = 0.48) and were, with the exception of 1 sow in the probiotic group (third parity), in their first or second gestation (1.6 ± 0.13). From the initial 26 gestating sows, 4 probiotic fed sows and 2 control sows were excluded from the trial for either not meeting the exclusion criteria of 9 live born piglets or when adjustment of litter size at the end of the first day of lactation was not possible. The number of piglets per litter born live and dead as well as nursed piglets at d 3, 7, 14, and 28 of life, respectively, did not differ (Table 2). Animal losses during the nursing period were highest in the control group, increasing from 12.4% on d 3 of lactation to 22.3% until weaning. Respective losses were numerically lower (3.6 and 16.2%) for the probiotic group. Piglet losses especially during the first 3 d of life tended to be smaller in the probiotic group (P = 0.09).

Pathogenicity Genes of Escherichia coli Isolates
The E. coli isolates derived from weekly fecal samples of nursed piglets were characterized regarding the occurrence of 9 pathogenicity genes (i.e., 4 toxin and 5 fimbriae genes). Colony-forming units of total fecal E. coli were comparable between treatment groups and averaged 3.1 (± 1.0) x 10⁹ cfu/g feces and 3.3 (± 2.4) x 10⁸ cfu/g before and after weaning, respectively (data not shown). Isolates carrying pathogenicity genes were found in each single control sample, while 1 probiotic piglet each on d 7 and 14 harbored solely negative isolates (data not shown). The studied 440 E. coli isolates carried out of 512 possible combinations of 9 pathogenicity genes each gene alone as well as 17, 7, 4, and 1 different combinations of 2, 3, 4, and 5 genes, respectively. The E. coli isolates with more than 2 pathogenicity genes were rare, exhibiting their highest frequency of 10% in the control group on d 28, where they were shed by 3 out of 5 examined animals (Table 4). Before the 28th day, isolates without any pathogenicity gene (negative isolates) were the most abundant group, averaging 47 and 52% of all isolates in this period in the control and probiotic group, respectively. Isolates with pathogenicity genes carried mostly just 1 or a combination of 2 of the examined genes with mean frequencies between 20 to 42% and 10 to 65%, respectively, depending on group and sampling age (Table 4).

Table 5 gives the percentage of total E. coli isolates, which were positive for at least one of the dominant pathogenicity genes, per treatment group and per sampling day. In addition, the number of animals shedding those isolates is supplied. The distribution and frequency of each pathogenicity gene and their combinations varied widely between both treatment groups. Adhesion genes occurred by far less often than toxin genes in isolates of the dominant E. coli population. Genes for the heat stable toxins II and I were most widely distributed between studied isolates of both treatment groups. Depending on sampling date, one-third or more of all isolates contained est2 or est1b as single gene or in combination with other pathogenicity genes, whereas the most prominent adhesion gene fimf41a occurred always in less than 16% of all isolates (Table 5). With weaning, the frequency of isolates carrying pathogenicity genes, especially est2 and est1b increased, whereas negative isolates decreased to 8 and 20% of all isolates 1 wk after weaning in the control and probiotic group, respectively (Table 4). At this time point est2 and est1b were primarily detected in both treatment groups in isolates carrying both genes in combination (Table 5).

	DISCUSSION

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On the other hand, overall performance of piglets did not show any significant changes for ADG, ADFI, and G:F ratio. While other studies with piglets and poultry show that probiotics may exert positive effects on animals, in particular on feces consistency, most trials revealed only insignificant increases in weight gain or feed conversion (Vanbelle et al., 1990; Simon et al., 2001). A recently published trial (Broom et al., 2005), using the same probiotic preparation as we did, detected no influence on piglet performance. They cite as possible explanation the postulate that growth promotional compounds become more effective as the environmental and nutritional challenges confronting the animal are exacerbated (Madec et al., 1998; Cromwell, 2000). Despite debarment from antibiotic use, relatively high preweaning mortality, and postweaning diarrhea incidence, the conditions in this study might not have been severe enough to allow positive performance effects. An indication of this might be the short and self-limiting duration of diarrhea and the low pathogenicity gene frequency, especially of adhesion genes, some of which are of pathogenic importance (Frydendahl, 2002). The decreased incidence of liquid feces and the duration of diarrhea were comparable to an earlier feeding trial with piglets and the same probiotic (Männer and Spieler, 1997), in which the piglets were orally dosed on the first and fourth day of life, following which they received the probiotic in starter and fattening diets. As seen in the trial from Männer and Spieler (1997), in which sow diets did not receive probiotic supplementation, it may be assumed that oral dosing acts in the same manner as probiotic transmission by maternal feces to young nursed piglets. Such observations occurred in this study and have already been reported (Macha et al., 2004). Indirect probiotic colonization via sow feces might be accompanied by the advantageous effects of an altered fecal microbiota as well as imaginable modifications of immunogenic factors in sow feces and milk (Schanler, 2000). Whether by direct or indirect action, probiotic treatment had an impact on diarrhea incidence and possibly also on occurrence of potentially pathogenic E. coli isolates. However, distribution and frequency of genes for virulence factors and their combinations varied widely within both supplementation groups. We detected mainly isolates without any pathogenicity genes and found adhesion genes only in low frequencies, which is comparable with early studies (Kwon et al., 1999; Osek, 1999), but which focused on diarrheic piglets. Frydendahl (2002) suggested the detection of the genes fae and fedA for the adhesion factors F4 and F18 as operational alternatives when diagnosing postweaning diarrhea. Both genes were in general quite rare in our study of healthy piglets (fae and fedA < 5% with the exception of d 28), which should be expected under the before-mentioned assumption. Therefore, to identify the causative agents of diarrhea, a closer look at the diseased animals is necessary with regard to the E. coli strains, which at the respective time are dominant and specific for the individual animal, and to determine the immunological status of this animal, which is the decisive element when dealing with opportunistic pathogens. On the other side, it is reasonable to characterize the pattern of opportunistic pathogens in healthy piglets as we have done to enable a thorough interpretation on this basis. Earlier studies have concentrated on samples from diseased piglets (Kwon et al., 1999; Osek, 1999; Frydendahl, 2002; Ha et al., 2003; Osek, 2003) and made no intent to study the high fluctuation of dominant fecal E. coli clones over time, which has been reported for humans (Schlager et al., 2002). We characterized this indeed highly dynamic composition of pathogenicity genes of fecal E. coli isolates, which have to be considered as part of the commensal microbiota and which reflect the background from which intestinal diseases might emerge, in asymptomatic piglets. In our trial, negative isolates displayed numerical slightly greater frequencies in the probiotic group in the first 14 d of life as well as 1 wk after weaning. Both periods are considered as decisive, one for the development of early colonization, the other for mastering the stressful weaning transition. Parallel investigations of intestinal tissue and digesta of killed piglets in this study found an influence of probiotic supplementation on microbial composition, especially E. coli serovar O141, as well as a decline of intraepithelial CD8 positive lymphocytes (Scharek et al., 2005). Both observations might be interrelated and could serve as indication of a lower pathogenic burden and a healthier development of probiotic-treated piglets. The data of Pollmann et al. (2005), which was derived from samples obtained from these same sows and killed piglets for another objective, might point in a very similar direction. They demonstrated that the probiotic E. faecium reduced the rate of carryover infections by obligate intracellular Chlamydia of piglets born to Chlamydia-infected sows. Further studies as well as a more detailed analysis of the influence of the probiotic on other members of the autochthonous microbiota are already in process and should elucidate the mechanisms of probiotic action by integrative assessment of the multidisciplinary data from this ongoing project.

	Footnotes

 
¹ This study was supported by the German Research Foundation (DFG) – FOR438. The authors wish to thank S. Weinholz for technical assistance and F. Antonelli as well as G. Arndt for advice and help in statistical evaluation of the data.

² Corresponding author: dtaras{at}zedat.fu-berlin.de

Received for publication December 17, 2004. Accepted for publication November 7, 2005.

	LITERATURE CITED

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Abbott, A. 2004. Microbiology: Gut reaction. Nature 427:284–286.[Medline]

Benyacoub, J., G. L. Czarnecki-Maulden, C. Cavadini, T. Sauthier, R. E. Anderson, E. J. Schiffrin, and T. von der Weid. 2003. Supplementation of food with Enterococcus faecium (SF68) stimulates immune functions in young dogs. J. Nutr. 133:1158–1162.[Abstract/Free Full Text]

Broom, L. J., H. M. Miller, K. G. Kerr, and J. S. Knapp. 2006. Effects of zinc oxide and Enterococcus faecium SF68 dietary supplementation on the performance, intestinal microbiota and immune status of weaned piglets. Res. Vet. Sci. 80:45–54.[Medline]

Cromwell, G. L. 2000. Antimicrobial and promicrobial agents. Pages 401–426 in Swine Nutrition. 2nd ed. A. J. Lewis and L. L. Southern, ed. CRC Press, Washington, DC.

EC No. 1831/2003. 2003. Regulation (EC) No. 1831/2003 of the European Parliament and of the Council of 23 September 2003 on additives for use in animal nutrition. Offic. J. Eur. Union L268:29–43.

Frydendahl, K. 2002. Prevalence of serogroups and virulence genes in Escherichia coli associated with postweaning diarrhoea and edema disease in pigs and a comparison of diagnostic approaches. Vet. Microbiol. 85:169–182.[Medline]

Fuller, R. 1989. Probiotics in man and animals. J. Appl. Bacteriol. 66:365–378.[Medline]

Göbel, S. 2003. Multiplex-Polymerase-Ketten-Reaktion (mPCR) zum Nachweis ausgewählter Virulenzfaktoren schweinepathogener Escherichia coli — Einsatz bei Ferkeln mit Bacillus cereus var. toyoi Zulage. Inaugural-Dissertation, Freie Universität Berlin, Berlin, Germany.

Göransson, L. 2001. Alternatives to antibiotics—The influence of new feeding strategies for pigs on biology and performance. Pages 39–50 in Recent Developments in Pig Nutrition 3. P. C. Garnsworthy and J. Wiseman, ed. Nottingham Univ. Press, Nottingham, UK.

Ha, S. K., C. Choi, and C. Chae. 2003. Prevalence of a gene encoding adhesin involved in diffuse adherence among Escherichia coli isolates in pigs with postweaning diarrhea or edema disease. J. Vet. Diagn. Invest. 15:378–381.[Abstract/Free Full Text]

Jadamus, A., W. Vahjen, and O. Simon. 2001. Growth behaviour of a spore forming probiotic strain in the gastrointestinal tract of broiler chicken and piglets. Arch. Anim. Nutr. 54:1–17.

Jensen, B. B. 1998. The impact of feed additives on the microbial ecology of the gut in young pigs. J. Anim. Feed Sci. 7:45–64.

Kwon, D., O. Kim, and C. Chae. 1999. Prevalence of genotypes for fimbriae and enterotoxins and of O serogroups in Escherichia coli isolated from diarrheic piglets in Korea. J. Vet. Diagn. Invest. 11:146–151.[Abstract/Free Full Text]

Kyriakis, S. C., V. K. Tsiloyiannis, J. Vlemmas, K. Sarris, A. C. Tsinas, C. Alexopoulos, and L. Jansegers. 1999. The effect of probiotic LSP 122 on the control of post-weaning diarrhoea syndrome of piglets. Res. Vet. Sci. 67:223–228.[Medline]

Macha, M., D. Taras, W. Vahjen, A. Arini, and O. Simon. 2004. Specific enumeration of the probiotic strain Enterococcus faecium NCIMB 10415 in the intestinal tract and in faeces of piglets and sows. Arch. Anim. Nutr. 58:443–452.[Medline]

Madec, F., N. Bridoux, S. Bounaix, and A. Jestin. 1998. Measurement of digestive disorders in the piglet at weaning and related risk factors. Prev. Vet. Med. 35:53–72.[Medline]

Männer, K., and A. Spieler. 1997. Probiotics in piglets—An alternative to traditional growth promoters. Micoecol. Ther. 26:243–256.

Naumann, C., and R. Bassler. 1993. Die chemische Untersuchung von Futtermitteln. VDLUFA-Verlag, Darmstadt.

Nordhoff, M., D. Taras, M. Macha, K. Tedin, H.-J. Busse, and L. H. Wieler. 2005. Treponema berlinense sp. nov. and Treponema porcinum sp. nov., novel spirochaetes isolated from porcine faeces. Int. J. Syst. Evol. Microbiol. 55:1675–1680.[Abstract/Free Full Text]

NRC. 1998. Nutrient requirements of swine. 10th rev. ed. Natl. Acad. Press, Washington, DC.

Osek, J. 1999. Prevalence of virulence factors of Escherichia coli strains isolated from diarrheic and healthy piglets after weaning. Vet. Microbiol. 68:209–217.[Medline]

Osek, J. 2003. Detection of the enteroaggregative Escherichia coli heat-stable enterotoxin 1 (EAST1) gene and its relationship with fimbrial and enterotoxin markers in E. coli isolates from pigs with diarrhoea. Vet. Microbiol. 91:65–72.[Medline]

Pollmann, M., M. Nordhoff, A. Pospischil, K. Tedin, and L. H. Wieler. 2005. Effects of a probiotic strain of Enterococcus faecium on the rate of natural chlamydia infection in swine. Infect. Immun. 73:4346–4353.[Abstract/Free Full Text]

Schanler, R. J. 2000. Overview: The clinical perspective. J. Nutr. 130:417S–419S.

Scharek, L., J. Guth, K. Reiter, K. D. Weyrauch, D. Taras, P. Schwerk, P. Schierack, M. F. G. Schmidt, L. H. Wieler, and K. Tedin. 2005. Influence of a probiotic Enterococcus faecium strain on development of the immune system of sows and piglets. Vet. Immunol. Immunopathol. 105:151–161.[Medline]

Schlager, T. A., J. O. Hendley, A. L. Bell, and T. S. Whittam. 2002. Clonal diversity of Escherichia coli colonizing stools and urinary tracts of young girls. Infect. Immun. 70:1225–1229.[Abstract/Free Full Text]

Simmering, R., and M. Blaut. 2001. Pro- and prebiotics—The tasty guardian angels? Appl. Microbiol. Biotechnol. 55:19–28.[Medline]

Simon, O., A. Jadamus, and W. Vahjen. 2001. Probiotic feed additives—Effectiveness and expected modes of action. J. Anim. Feed Sci. 10:51–67.

Tannock, G. W. 1999. Introduction. Pages 1–4 in Probiotics: A critical review. G. W. Tannock, ed. Horizon Sci. Press, Wymondham, UK.

Taras, D., W. Vahjen, M. Macha, L. Scharek, K. Tedin, L. H. Wieler, M. F. G. Schmidt, and O. Simon. 2004. Does maternal microbiota act as an intermediate agent for probiotic action in suckling piglets? Reprod. Nutr. Dev. 44(Suppl. 1):S36. (Abstr.)

Underdahl, N. R. 1983. The effect of feeding Streptococcus faecium upon Escherichia coli induced diarrhea in gnotobiotic pigs. Prog. Food Nutr. Sci. 7:5–12.[Medline]

Vanbelle, M., E. Teller, and M. Focant. 1990. Probiotics in animal nutrition: A review. Arch. Anim. Nutr. 40:543–567.

Wenk, C. 2003. Growth promoter alternatives after the ban on antibiotics. Pig News Info. 24:11N–16N.

Wunderlich, P. F., L. Braun, I. Fumagalli, V. D’Apuzzo, F. Heim, M. Karly, R. Lodi, G. Politta, F. Vonbank, and L. Zeltner. 1989. Double-blind report on the efficacy of lactic acid-producing Enterococcus SF68 in the prevention of antibiotic-associated diarrhoea and in the treatment of acute diarrhoea. J. Int. Med. Res. 17:333–338.[Medline]

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