1
|
Rajova J, Zeman M, Seidlerova Z, Vlasatikova L, Matiasovicova J, Sebkova A, Faldynova M, Prikrylova H, Karasova D, Crhanova M, Kulich P, Babak V, Volf J, Rychlik I. In Vivo Expression of Chicken Gut Anaerobes Identifies Carbohydrate- or Amino Acid-Utilising, Motile or Type VI Secretion System-Expressing Bacteria. Int J Mol Sci 2024; 25:6505. [PMID: 38928209 PMCID: PMC11204068 DOI: 10.3390/ijms25126505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/05/2024] [Accepted: 06/09/2024] [Indexed: 06/28/2024] Open
Abstract
Complex gut microbiota increases chickens' resistance to enteric pathogens. However, the principles of this phenomenon are not understood in detail. One of the possibilities for how to decipher the role of gut microbiota in chickens' resistance to enteric pathogens is to systematically characterise the gene expression of individual gut microbiota members colonising the chicken caecum. To reach this aim, newly hatched chicks were inoculated with bacterial species whose whole genomic sequence was known. Total protein purified from the chicken caecum was analysed by mass spectrometry, and the obtained spectra were searched against strain-specific protein databases generated from known genomic sequences. Campylobacter jejuni, Phascolarctobacterium sp. and Sutterella massiliensis did not utilise carbohydrates when colonising the chicken caecum. On the other hand, Bacteroides, Mediterranea, Marseilla, Megamonas, Megasphaera, Bifidobacterium, Blautia, Escherichia coli and Succinatimonas fermented carbohydrates. C. jejuni was the only motile bacterium, and Bacteroides mediterraneensis expressed the type VI secretion system. Classification of in vivo expression is key for understanding the role of individual species in complex microbial populations colonising the intestinal tract. Knowledge of the expression of motility, the type VI secretion system, and preference for carbohydrate or amino acid fermentation is important for the selection of bacteria for defined competitive exclusion products.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Ivan Rychlik
- Veterinary Research Institute, CZ6210 Brno, Czech Republic; (J.R.); (M.Z.); (Z.S.); (L.V.); (J.M.); (A.S.); (M.F.); (H.P.); (D.K.); (M.C.); (P.K.); (V.B.); (J.V.)
| |
Collapse
|
2
|
Marcolla CS, Ju T, Lantz HL, Willing BP. Investigating the cecal microbiota of broilers raised in extensive and intensive production systems. Microbiol Spectr 2023; 11:e0235223. [PMID: 37754552 PMCID: PMC10581045 DOI: 10.1128/spectrum.02352-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 08/10/2023] [Indexed: 09/28/2023] Open
Abstract
Intensive broiler production practices are structured to prevent the introduction and spread of pathogens; however, they can potentially minimize the exposure of broilers to beneficial commensal bacteria. In this study, we used 16S rRNA amplicon sequencing to characterize the cecal microbiota of 35-day-old broilers from 22 independent commercial farms rearing broilers under intensive (IPS) or extensive production systems (EPS). We aimed to determine which bacteria are normal inhabitants of the broiler ceca and which bacteria might be missing from broilers in IPS. In addition, we generated a collection of 410 bacterial isolates, including 87 different species, to be used as a resource to further explore the effects of selected isolates on bird physiology and to elucidate the role of individual species within the cecal microbial community. Our results indicated significant differences in the microbiota of broilers between systems: the microbiota of broilers from EPS was dominated by Bacteroidetes {55.2% ± 8.9 [mean ± standard deviation (SD)]}, whereas Firmicutes dominated the microbiota of broilers from IPS (61.7% ± 14.4, mean ± SD). Bacterial taxa found to be core in the EPS microbiota, including Olsenella, Alistipes, Bacteroides, Barnesiella, Parabacteroides, Megamonas, and Parasutterella, were shown to be infrequent or absent from the IPS microbiota, and the EPS microbiota presented higher phylogenetic diversity and greater predicted functional potential than that of broilers in IPS. The bacteria shown to be depleted in broilers from IPS should be further investigated for their effects on bird physiology and potential application as next-generation probiotics. IMPORTANCE Production practices in intensive farming systems significantly reduce the introduction and spread of pathogens; however, they may potentially minimize the exposure of animals to beneficial commensal microorganisms. In this study, we identified core bacteria from the cecal microbiota of broilers raised in extensive production systems that are missing or reduced in birds from intensive systems, including Olsenella, Alistipes, Bacteroides, Barnesiella, Parabacteroides, Megamonas, and Parasutterella. Furthermore, the cecal microbiota of broilers from extensive systems showed higher diversity and greater functional potential than that of broilers from intensive systems. In addition, a collection of bacterial isolates containing 87 different species was generated from the current study, and this important resource can be used to further explore the role of selected commensal bacteria on the microbial community and bird physiology.
Collapse
Affiliation(s)
- Camila S. Marcolla
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Tingting Ju
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Hannah L. Lantz
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Benjamin P. Willing
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
| |
Collapse
|
3
|
Papouskova A, Rychlik I, Harustiakova D, Cizek A. Research Note: A mixture of Bacteroides spp. and other probiotic intestinal anaerobes reduces colonization by pathogenic E. coli strain O78:H4-ST117 in newly hatched chickens. Poult Sci 2023; 102:102529. [PMID: 36805398 PMCID: PMC9969313 DOI: 10.1016/j.psj.2023.102529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/18/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
An experimental group of one-day-old chicken from a commercial hatchery was given a defined mixture of 7 gut anaerobes. The next day the chicks were inoculated by an APEC strain O78:H4-ST117 resistant to ciprofloxacin, alongside with the control group and monitored for 4 wk after the inoculation for the presence of the colonizing strains and ciprofloxacin-resistant E. coli. Significant reduction of colonization rates in the first 2 wk was recorded in the experimental group for the numbers of ciprofloxacin-resistant E. coli. The results show that colonization of chicken by defined anaerobic mixtures may provide a decisive protection during the critical period of the chicken intestinal microflora development.
Collapse
Affiliation(s)
- Aneta Papouskova
- Institute of Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, The Czech Republic.
| | - Ivan Rychlik
- Veterinary Research Institute, Brno, The Czech Republic
| | - Danka Harustiakova
- RECETOX, Faculty of Science, Masaryk University, Brno, The Czech Republic
| | - Alois Cizek
- Institute of Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, The Czech Republic
| |
Collapse
|
4
|
Rychlik I, Karasova D, Crhanova M. Microbiota of Chickens and Their Environment in Commercial Production. Avian Dis 2023; 67:1-9. [PMID: 37140107 DOI: 10.1637/aviandiseases-d-22-00048] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 11/04/2022] [Indexed: 01/24/2023]
Abstract
Chickens in commercial production are subjected to constant interaction with their environment, including the exchange of microbiota. In this review, we therefore focused on microbiota composition in different niches along the whole line of chicken production. We included a comparison of microbiota of intact eggshells, eggshell waste from hatcheries, bedding, drinking water, feed, litter, poultry house air and chicken skin, trachea, crop, small intestine, and cecum. Such a comparison showed the most frequent interactions and allowed for the identification of microbiota members that are the most characteristic for each type of sample as well as those that are the most widespread in chicken production. Not surprisingly, Escherichia coli was the most widely distributed species in chicken production, although its dominance was in the external aerobic environment and not in the intestinal tract. Other broadly distributed species included Ruminococcus torque, Clostridium disporicum, and different Lactobacillus species. The consequence and meaning of these and other observations are evaluated and discussed.
Collapse
Affiliation(s)
- Ivan Rychlik
- Veterinary Research Institute, Brno 621 00, Czech Republic
| | | | | |
Collapse
|
5
|
Abstract
Chickens are in constant interaction with their environment, e.g., bedding and litter, and their microbiota. However, how litter microbiota develops over time and whether bedding and litter microbiota may affect the cecal microbiota is not clear. We addressed these questions using sequencing of V3/V4 variable region of 16S rRNA genes of cecal, bedding, and litter samples from broiler breeder chicken flocks for 4 months of production. Cecal, bedding, and litter samples were populated by microbiota of distinct composition. The microbiota in the bedding material did not expand in the litter. Similarly, major species from litter microbiota did not expand in the cecum. Only cecal microbiota was found in the litter forming approximately 20% of total litter microbiota. A time-dependent development of litter microbiota was observed. Escherichia coli, Staphylococcus saprophyticus, and Weissella jogaejeotgali were characteristic of fresh litter during the first month of production. Corynebacterium casei, Lactobacillus gasseri, and Lactobacillus salivarius dominated in a 2-month-old litter, Brevibacterium, Brachybacterium, and Sphingobacterium were characteristic for 3-month-old litter, and Salinococcus, Dietzia, Yaniella, and Staphylococcus lentus were common in a 4-month-old litter. Although the development was likely determined by physicochemical conditions in the litter, it might be interesting to test some of these species for active modification of litter to improve the chicken environment and welfare. IMPORTANCE Despite intimate contact, the composition of bedding, litter, and cecal microbiota differs considerably. Species characteristic for litter microbiota at different time points of chicken production were identified thus opening the possibility for active manipulation of litter microbiota.
Collapse
|
6
|
Singh N, Singh V, Rai SN, Mishra V, Vamanu E, Singh MP. Deciphering the gut microbiome in neurodegenerative diseases and metagenomic approaches for characterization of gut microbes. Biomed Pharmacother 2022; 156:113958. [DOI: 10.1016/j.biopha.2022.113958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/26/2022] [Accepted: 11/01/2022] [Indexed: 11/09/2022] Open
|
7
|
Rzeznitzeck J, Hoerr FJ, Rychlik I, Methling K, Lalk M, Rath A, von Altrock A, Rautenschlein S. Morphology, microbiota, and metabolome along the intestinal tract of female turkeys. Poult Sci 2022; 101:102046. [PMID: 36130451 PMCID: PMC9489512 DOI: 10.1016/j.psj.2022.102046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/24/2022] [Accepted: 06/29/2022] [Indexed: 11/28/2022] Open
Affiliation(s)
- Janina Rzeznitzeck
- Clinic for Poultry, University of Veterinary Medicine Hannover, Foundation, 30559 Hannover, Germany
| | | | - Ivan Rychlik
- Veterinary Research Institute, 621 00 Brno, Czech Republic
| | - Karen Methling
- Institute of Biochemistry, University of Greifswald, 17487 Greifswald, Germany
| | - Michael Lalk
- Institute of Biochemistry, University of Greifswald, 17487 Greifswald, Germany
| | - Alexandra Rath
- Clinic for Swine, Small Ruminants and Forensic Medicine, University of Veterinary Medicine Hannover, Foundation, 30173 Hannover, Germany
| | - Alexandra von Altrock
- Clinic for Swine, Small Ruminants and Forensic Medicine, University of Veterinary Medicine Hannover, Foundation, 30173 Hannover, Germany
| | - Silke Rautenschlein
- Clinic for Poultry, University of Veterinary Medicine Hannover, Foundation, 30559 Hannover, Germany.
| |
Collapse
|
8
|
Karasova D, Faldynova M, Matiasovicova J, Sebkova A, Crhanova M, Kubasova T, Seidlerova Z, Prikrylova H, Volf J, Zeman M, Babak V, Juricova H, Rajova J, Vlasatikova L, Rysavka P, Rychlik I. Host Species Adaptation of Obligate Gut Anaerobes Is Dependent on Their Environmental Survival. Microorganisms 2022; 10:microorganisms10061085. [PMID: 35744604 PMCID: PMC9229247 DOI: 10.3390/microorganisms10061085] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/19/2022] [Accepted: 05/23/2022] [Indexed: 01/27/2023] Open
Abstract
The gut microbiota of warm-blooded vertebrates consists of bacterial species belonging to two main phyla; Firmicutes and Bacteroidetes. However, does it mean that the same bacterial species are found in humans and chickens? Here we show that the ability to survive in an aerobic environment is central for host species adaptation. Known bacterial species commonly found in humans, pigs, chickens and Antarctic gentoo penguins are those capable of extended survival under aerobic conditions, i.e., either spore-forming, aerotolerant or facultatively anaerobic bacteria. Such bacteria are ubiquitously distributed in the environment, which acts as the source of infection with similar probability in humans, pigs, chickens, penguins and likely any other warm-blooded omnivorous hosts. On the other hand, gut anaerobes with no specific adaptation for survival in an aerobic environment exhibit host adaptation. This is associated with their vertical transmission from mothers to offspring and long-term colonisation after administration of a single dose. This knowledge influences the design of next-generation probiotics. The origin of aerotolerant or spore-forming probiotic strains may not be that important. On the other hand, if Bacteroidetes and other host-adapted species are used as future probiotics, host preference should be considered.
Collapse
Affiliation(s)
- Daniela Karasova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Marcela Faldynova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Jitka Matiasovicova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Alena Sebkova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Magdalena Crhanova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Tereza Kubasova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Zuzana Seidlerova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Hana Prikrylova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Jiri Volf
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Michal Zeman
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
- Department of Experimental Biology, Czech Collection of Microorganisms, Faculty of Science, Masaryk University, 625 00 Brno, Czech Republic
| | - Vladimir Babak
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Helena Juricova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Jana Rajova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Lenka Vlasatikova
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
| | - Petr Rysavka
- Medi Pharma Vision Ltd., 612 00 Brno, Czech Republic;
| | - Ivan Rychlik
- Veterinary Research Institute, 621 00 Brno, Czech Republic; (D.K.); (M.F.); (J.M.); (A.S.); (M.C.); (T.K.); (Z.S.); (H.P.); (J.V.); (M.Z.); (V.B.); (H.J.); (J.R.); (L.V.)
- Correspondence: ; Tel.: +420-533-331-201
| |
Collapse
|
9
|
Wang X, Wu X, Cong X, Ren J, Li J, Zhu J, Dai M, Hrabchenko N, Du Y, Qi J. The functional role of fecal microbiota transplantation on Salmonella Enteritidis infection in chicks. Vet Microbiol 2022; 269:109449. [DOI: 10.1016/j.vetmic.2022.109449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 04/07/2022] [Accepted: 04/30/2022] [Indexed: 11/28/2022]
|
10
|
Wang H, Li J, Wu G, Zhang F, Yin J, He Y. The effect of intrinsic factors and mechanisms in shaping human gut microbiota. MEDICINE IN MICROECOLOGY 2022. [DOI: 10.1016/j.medmic.2022.100054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
11
|
Yuan X, Xue H, Xu X, Jiao X, Pan Z, Zhang Y. Closely related Salmonella Derby strains triggered distinct gut microbiota alteration. Gut Pathog 2022; 14:6. [PMID: 35078518 PMCID: PMC8787955 DOI: 10.1186/s13099-022-00480-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 01/13/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Salmonella Derby is one of the most predominant Salmonella serotypes that seriously threatens food safety. This bacterium can be further differentiated to sub-populations with different population sizes; however, whether and how the S. Derby–gut microbiota interactions affect epidemic patterns of S. Derby sub-populations remain largely unknown.
Results
We selected two representative strains, 14T and 14C, which represent rarely distributed and prevalent sub-populations of the S. Derby ST40 group, respectively, to address this question using a mouse model. Effects of oral administration of both strains was monitored for 14 days. Alpha diversity of gut microbiota at early stages of infection (4 h post infection) was higher in 14C-treated mice and lower in 14T-treated mice compared with controls. Strain 14T triggered stronger inflammation responses but with lower pathogen titer in spleen compared with strain 14C at 14 days post infection. Certain known probiotic bacteria that can hinder colonization of Salmonella, such as Bifidobacteriaceae and Akkermansiaceae, exhibited increased relative abundance in 14T-treated mice compared with 14C-treated mice. Our results also demonstrated that Ligilactobacillus strains isolated from gut microbiota showed stronger antagonistic activity against strain 14T compared with strain 14C.
Conclusions
We identified how S. Derby infection affected gut microbiota composition, and found that the 14T strain, which represented a rarely distributed S. Derby sub-population, triggered stronger host inflammation responses and gut microbiota disturbance compared with the 14C strain, which represented a prevalent S. Derby sub-population. This study provides novel insights on the impacts of gut microbiota on the epidemic patterns of Salmonella populations.
Collapse
|
12
|
Juricova H, Matiasovicova J, Faldynova M, Sebkova A, Kubasova T, Prikrylova H, Karasova D, Crhanova M, Havlickova H, Rychlik I. Probiotic Lactobacilli Do Not Protect Chickens against Salmonella Enteritidis Infection by Competitive Exclusion in the Intestinal Tract but in Feed, Outside the Chicken Host. Microorganisms 2022; 10:microorganisms10020219. [PMID: 35208674 PMCID: PMC8877478 DOI: 10.3390/microorganisms10020219] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 01/16/2022] [Accepted: 01/17/2022] [Indexed: 12/21/2022] Open
Abstract
Lactobacilli are commonly used as probiotics in poultry to improve production parameters and to increase chicken resistance to enteric infections. However, lactobacilli do not efficiently colonise the chicken intestinal tract, and also, their anti-infection effect in vivo is sometimes questionable. In this study, we therefore evaluated the potential of a mixture of four Lactobacillus species (L. salivarius, L. reuteri, L. ingluviei and L. alvi) for the protection of chickens against Salmonella Enteritidis infection. Whenever the chickens were inoculated by lactobacilli and S. Enteritidis separately, there was no protective effect of lactobacilli. This means that when lactobacilli and S. Enteritidis are exposed to each other as late as in the crop of chickens, lactobacilli did not influence chicken resistance to S. Enteritidis at all. The only positive effect was recorded when the mixture of lactobacilli and S. Enteritidis was used for the inoculation of feed and the feed was anaerobically fermented for 1 to 5 days. In this case, chickens fed such a diet remained S. Enteritidis negative. In vitro experiments showed that the protective effect was caused by acidification of feed down to pH 4.6 due to lactobacilli fermentation and was associated with S. Enteritidis inactivation. The probiotic effect of lactobacilli was thus expressed in the feed, outside the chicken host.
Collapse
|