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Production Layer Salmonella Enteritidis Control through Dry Fed Pre & Probiotic Products

ABSTRACT

Increasing interest in multiple strain Bacillus probiotics and parietal yeast fractions as feed ingredients for egg laying hen diets has also led to food safety questions. This study was undertaken to evaluate the ability of these products to reduce Salmonella Enteritidis colonization. Sixty Hy-Line hens aged 56 weeks were placed in individual cages and fed a mash diet containing one of the following treatments, control, Bacillus spp. probiotic, yeast cell wall, or a combination of yeast cell wall and Bacillus probiotic. At 60 weeks of age all hens were challenged orally with 7 x 107 CFU/bird of Salmonella Enteritidis. At 61 weeks of age, birds were humanely euthanized, by cervical dislocation and the ceca aseptically removed and cultured for S. Enteritidis prevalence and number by the Most Probable Number method. There was no significant difference in prevalence of Salmonella Enteritidis between the control and any treatments. The control birds had 4.37 log10 MPN/g of S. Enteritidis detected in the ceca. The Probiotic group had 2.96 MPN/g, a reduction of 1.41(p<0.05) and the yeast cell wall group had 2.89 MPN/g a reduction of 1.48 (p<0.05). The combination had 3.60 MPN/g a numerical reduction of 0.78 (p=0.14). The yeast cell wall and Bacillus probiotic groups significantly reduced the amount of Salmonella Enteritidis in the ceca of the laying hens.

Keywords:
Bacillus; laying hens; Salmonella Enteritidis; probiotic; yeast cell wall

INTRODUCTION

Salmonella is commonly associated with poultry and poultry products, often resulting in highly publicized outbreaks of foodborne illnesses. Concerns over foodborne illnesses and the associated outbreaks have led to a focus on live animal pathogen control strategies. Salmonella annually causes an estimated 93 million enteric infections worldwide and 155,000 deaths (Majowicz, 2010Majowicz SE, Musto J, Scallan E, Angulo FJ, O'Brein SJ, Jones TF, The global burden of nontyphoidal Salmonella gastroenteritis. Clinical Infectious Diseases 2010;50:882-889.). The Centers for Disease Control and Prevention estimate Salmonella is responsible for over 1.2 million illnesses in the United States, and that 1 million of these cases are the result of foodborne Salmonella infections (Galanis, 2006Galanis E, Wong D, Patrick ME, Binsztein N, Cieslik A, Chalermchaikit T, et al. Web-based surveillance and global salmonella distribution, 2000-2002. Emerging Infectious Diseases. 2006;12(3):381-388.). Salmonella enterica serotypes Typhimurium and Enteritidis are the most common in human infections associated with animals worldwide (Herikstad, 2002Herikstad H, Motarjemi Y, Tauxe RV.Salmonella surveillance: a global survey of public health serotyping. Epidemiology and Infection 2002;129:1-8.; Afshari, 2018Afshari A, Baratpour A, Khanzade S, Jamshidi A. Salmonella enteritidis and Salmonella Typhimurium identification in poultry carcasses. Iran Journal of Microbiology 2018;10(1):45-50.). Data from the United States Department of Agriculture Food Safety and Inspection Service (USDA-FSIS) shows that over 9% of all Salmonella positives are caused by S. Enteritidis (USDA-FSIS 2016). Current interventions used in live production for Salmonella control in the U.S. poultry industry consist of a mixture of biosecurity, nutritional and feed management, non-antimicrobial feed additives, and vaccines. The use of probiotics in poultry has been shown to alter microbial population and reduce the growth of pathogens (Fanning, 2018). It has been shown that Bacillus spp. probiotics can improve the efficiency of feed to gain nutrient utilization, and other production parameters (Park, 2015Park JH, Kim IH. The effects of the supplementation of Bacillus subtilis RX7 and B2A strains on the performance, blood profiles, intestinal Salmonella concentration, noxious gas emission, organ weight and breast meat quality of broiler challenged with Salmonella Typhimurium. Journal of Animal Physiology and Animal Nutrition 2015;99(2):326-334,). Poultry (Menconi, 2013Menconi A, Morgan MJ, Pumford NR, Hargis BM, Tellez G. Physiological properties and salmonella growth inhibition of probiotic bacillus strains isolated from environmental and poultry sources. International Journal of Bacteriology 2013;2013:958408), mice (O’Mahony, 2001O'Mahony L, Feeney M, O'Halloran S, Murphy L, Kiely B, Fitzgibbon J, et al. Probiotic impact on microbial flora, inflammation and tumour development in IL-10 knockout mice. Alimentary Pharmacology & Therapeutics 2001;15(8):1219-1225.), and human (Urdaci, 2004Urdaci MC, Bressollier P, Pinchuk I. Bacillus clausii probiotic strains: antimicrobial and immunomodulatory activities. Journal of Clinical Gastroenterology 2004;38(6 Suppl):S86-90.) models have all shown that Bacillus can influence the host immune system and compete for host attachment sites and nutrient utilization to detriment of Salmonella that may otherwise colonize the host. In poultry, Bacillus spp. delivered in feed has shown reduced Salmonella counts in the intestine, crop, and ceca. Some studies have shown reductions in prevalence as much as 72%, and increased reductions in number up to 1x103 CFU/g (Knap, 2011Knap I, Kehlet AB, Bennedsen M, Mathis GF, Hofacre CL, Lumpkins BS, et al. Bacillus subtilis (DSM17299) significantly reduces Salmonella in broilers. Poultry Science 2011;90(8):1690-1694.; Adhikari, 2019Adhikari B, Hernandez-Patlan D, Solis-Cruz B, Kwon YM, Arreguin MA, Latorre JD, et al. Evaluation of the antimicrobial and anti-inflammatory properties of bacillus-dfm (norum(tm)) in broiler chickens infected with salmonella enteritidis. Frontiers in Veterinary Science 2019;6:282.). Bacillus subtillus and Bacillus methylotrophicus treatments showed reduction in the load of Salmonella positive layers by over 1x101 CFU/g in a S. Gallinarum challenge (Upadhaya, 2016Upadhaya SA, Hossiendoust A, Kim IH. Probiotics in Salmonella-challenged Hy-Line brown layers. Poultry Science 2016;95(8):1894-1897.). Bacillus subtillus has also been effective in achieving reductions in S. Heidelberg in broiler chickens (Hayashi, 2018Hayashi RM, Lourenco CM, Krajeski AL, Araujo RB, Gonzales-Esquerro R, Leonardecz E, et al. Effect of feeding bacillus subtilis spores to broilers challenged with salmonella enterica serovar heidelberg brazilian strain ufpr1 on performance, immune response, and gut health. Frontiers in Veterinary Science 2018;5:13.).

Yeast is a well-documented prebiotic source for poultry and previous work has demonstrated control over a variety of foodborne pathogens in poultry production (Hatoum 2012Hatoum R, Labrie S, Fliss I. Antimicrobial and probiotic properties of yeasts: from fundamental to novel applications. Frontiers in Microbiology 2012;3:421., Huff 2010Huff GR, Huff WE, Farnell MB, Rath NC, Solis de Los Santos F, Donoghue AM. Bacterial clearance, heterophil function, and hematological parameters of transport-stressed turkey poults supplemented with dietary yeast extract. Poultry Science 2010;89(3):447-456., Roto 2015Roto SM, Rubinelli PM, Ricke SC. An introduction to the avian gut microbiota and the effects of yeast-based prebiotic-type compounds as potential feed additives. Frontiers in Veterinary Science 2015;2:28.). The use of non-digestible oligosaccharide prebiotics has also been shown to affect intestinal and immune function through a variety of factors (Revolledo, 2006Revolledo L, Ferreira AJ, Mead GC. Prospects in Salmonella control: competitive exclusion, probiotics, and enhancement of avian intestinal immunity. Journal of Applied Poultry Research 2006;15:341-51.; Sheng, 2006Sheng KC, Pouniotis DS, Wright MD, Tang CK, Lazoura E, Pietersz GA, Apostolopoulos V. Mannan derivatives induce phenotypic and functional maturation of mouse dendritic cells. Immunology. 2006;118:372-383.; Alloui, 2013Alloui MN, Szczurek W, Swiatkiewicz S. The usefulness of prebiotics and probiotics in modern poultry nutrition: a review. Annals of Animal Science 2013;13:17-32). Mannanoligosaccharides in particular are mannose-based oligomers that can influence cecal microbiota in broilers and layers due to their ability to reach the lower GI tract undigested (Pourabedin, 2015Pourabedin M, Zhao X. Prebiotics and gut microbiota in chickens. FEMS Microbiol Letters 2015;362(15):122). Mannanoligosaccharide supple-mentation has shown reduced Salmonella Enteritidis shedding from broiler chickens (Lourenço, 2015Lourenço MC, Kuritza LN, Hayashi RM, Miglino LB, Durau JF, Pickler L, et al. Effect of a mannanoligosaccharide-supplemented diet on intestinal mucosa T lymphocyte populations in chickens challenged with Salmonella Enteritidis. Journal of Applied Poultry Research. 2015;24(1):15-22.). Mannose from Saccharomyces cerevisiae has shown consistent potential for the binding of pathogenic bacteria with type-1 fimbriae, such as Salmonella, which can in turn lower CFU counts and prevalence in intestinal and fecal content culture (Oyofo, 1989Oyofo BA, Droleskey RE, Norman JO, Mollenhauer HH, Ziprin RL, Corrier DE, et al. Inhibition by mannose of in vitro colonization of chicken small intestine by Salmonella typhimurium. Poultry Science 1989;68:1351-1356.; Hooge, 2004Hooge DM. Meta-analysis of broiler chicken pen trials evaluating dietary mannan oligosaccharide, 1993-2003. International Journal of Poultry Science 2004;3:163-174; Cortés-Coronado, 2017Cortés-Coronado RF, Gómez-Rosales S, Angeles M de L, Casaubon-Huguenin MT, Sørensen-Dalgaard T. Influence of a yeast fermented product on the serum levels of the mannan-binding lectin and the antibodies against the Newcastle disease virus in Ross broilers. Journal of Applied Poultry Research 2017;26(1): 38-49). In the avian GI tract, the combination of mannanoligosaccharide and β-1,3 glucan in yeast cell can stimulate the epithelial cell lining junctions to strengthen and thereby reduce the flow of pathogens past the intestinal barrier (Shao, 2013Shao Y, Guo Y, Wang Z. β-1,3/1,6-glucan alleviated intestinal mucosal barrier impairment of broiler chickens challenged with Salmonella enterica serovar Typhimurium. Poultry Science 2013;92(7):1764-1773). Shanmugasundaram et al. (2013Shanmugasundaram R, Sifri M, Selvaraj RK. Effect of yeast cell product supplementation on broiler cecal microflora species and immune responses during an experimental coccidial infection. Poultry Science 2013;92:1195-2201.) showed that the dietary addition of the whole yeast cell wall can reduce the incidence of Salmonella due to the impact on coccidiosis (Shanmugasundaram, 2013). The specific serovars, S. Typhimurium (Price, 2019), S. Heidelberg (Kiros, 2019Kiros T, Gaydos T, Corley J, Raspoet R, Berghaus R, Hofacre C. Effect of Saccharomyces cerevisiae yeast products in reducing direct colonization and horizontal transmission of Salmonella Heidelberg in broilers. Journal of Applied Poultry Research 2019;28:23-30.), S. Enteritidis (Price, 2019b) have all been shown to have reduced numbers in poultry cecal by a commercially available yeast cell wall. This study focused on demonstrating the potential of a specific yeast cell wall, a multispecies probiotic, and their combination to reduce intestinal colonization of laying hens by Salmonella Enteritidis.

MATERIALS AND METHODS

Sixty, 56-week-old Hy-Line W-36 hens were purchased from a commercial layer company. Birds were provided with mash feed formulated to meet or exceed current NRC standards and water ad libitum throughout the duration of the trial. The unit for each treatment was fifteen (15) cages of a battery, therefore each cage became a replicate. Birds were randomly assigned to treatments: control, 500ppm yeast cell wall (YCW), 500ppm Bacillus spp. probiotic (PB), and a blend of 250ppm of YCW and 250ppm Probiotic (Combo). The YCW is a commercially available product with minimum guaranteed levels of mannan (20%) and β-glucan (20%). The Probiotic is a commercially available blend of Bacillus amyloliquefaciens, Bacillus licheniformis, and Bacillus pumilus. The treatment diets were fed for 4 weeks prior to inoculation of Salmonella.

Inoculum preparation

A nalidixic acid/ novobiocin resistant strain of Salmonella Enteritidis was aseptically removed from -80C storage and grown onto tryptic soy agar II (TSAII) plates supplemented with 5% sheep blood. Cultures were grown aerobically for 24 hrs at 37C. A single colony from the TSAII agar plate was inoculated into a brain - heart infusion (BHI) broth and incubated in a shaker incubator (200 rpm) overnight at 37C. The culture was diluted into phosphate buffered saline (PBS) to the estimated desired CFU/mL prior to inoculation and confirmed retrospectively by serial dilution and culture.

Inoculation and sample collection

At 60 weeks-of-age each bird was orally challenged with 1mL of 7 x 107 CFU/bird of a nalidixic acid/ novobiocin resistant strain of Salmonella Enteritidis. On seven (7) days post-challenge all hens were humanely euthanized by cervical dislocation, ceca were aseptically removed and placed into sterile plastic sampling bags. The samples were placed on ice for transportation to the lab for Salmonella analysis. The authors confirm that the ethical policies of the journal, as noted on the journal’s author guidelines page, have been adhered to and the appropriate ethical review committee approval has been received. The US National Research Council’s guidelines for the Care and Use of Laboratory Animals were followed.

Salmonella isolation, identification, and enumeration

Ceca samples were weighed and diluted in buffered peptone water BPW to give a 1:10 dilution. Each sample was then stomached for 1 minute ensure even mixing prior to serial dilution. Salmonella were enumerated using standard 10-fold serial dilution method. A 0.1mL aliquot was transferred to 0.9mL of PBS. This process was repeated creating (4) 10-fold dilutions. The dilution 10-1 was plated in triplicate using 0.1mL on a whole spread plate and the 10-2 to 10-4 dilutions were plated in triplicate using a 10uL micro drop technique onto Xylose Lysine Tergitol-4 (XLT-4) plates containing 100µg of nalidixic acid/mL and 15ug novobiocin/mL. Additionally, 1 ml of the ceca and BPW solution was placed into tubes containing 9 mL tetrathionate broth (TTB). These plates and tubes were incubated for 24 hrs at 37°C. After that time Salmonella was enumerated from the plates. To determine prevalence, for any samples that were negative for Salmonella in the enumeration step, one 10µL loop of the corresponding enrichment TTB tubes was streaked onto XLT-4 100µg of nalidixic acid/mL and 15ug novobiocin/mL. These plates were incubated for 24 hours at 37°C. After that time Salmonella prevalence was determined from the plates.

Statistics

Salmonella prevalence in ceca samples were compared between treatment groups using Fisher’s exact test. A Tobit censored regression model was used to compare treatment groups with respect to Salmonella MPNs in ceca samples while considering culture-negative samples to be left-censored at 4.477 log10 MPN/g (because the culture method’s lower limit of detection is 30 CFU at first dilution). For the comparison of Salmonella MPNs, samples with a negative culture result by the MPN method but a positive result by enrichment were arbitrarily assigned an MPN equal to one-half the minimum detection limit of the MPN assay. MPNs were log-transformed prior to statistical analysis. All statistical testing assumed a two-sided alternative hypothesis, and p<0.05 was considered significant. Analyses were performed using commercially available statistical software Stata (version 15.1, StataCorp LLC, College Station, TX) for Fisher’s exact test and R software for Tobit model (version 3.6.1., R Foundation for Statistical Computing, Vienna, Austria) with packages AER (Kleiber 2008Kleiber C. Applied econometrics with R. New York: Springer-Verlag; 2008. Available from: https://CRAN.R-project.org/package=AER.) and lmtest (Zeileis & Hothorn, 2002).

RESULTS AND DISCUSSION

The prevalence of SE in the ceca was similar between all treatments. The ceca in the control and Probiotic group were 93% positive for SE (14/15), the YCW group was 87% positive 13/15, and the Combo group 100% positive (15/15). The level of SE in the ceca, measured in log10 MPN/g, in the control group was 4.37. The level of SE was reduced by 1.41 logs in the Probiotic and 1.48 logs in the YCW group (p<0.05). The load of SE was numerically reduced compared to the control in the Combo group by 0.78 logs (p=0.14). These data are displayed in Figure 1. Salmonella spp. can bind to mannose via the type-1 binding fimbriae. The cell wall fraction of S. cerevisiae has been shown to bind a variety of gram negative organisms (Posadas, 2017Posadas GA, Broadway PR, Thornton JA, Carroll JA, Lawrence A, Corley J, et al. Yeast pro- and paraprobiotics have the capability to bind pathogenic bacteria associated with animal disease. Translational Animal Science 2017;1:60-68.). Reduction in S. Enteritidis levels in the ceca of layers will reduce the overall load in the environment leading to reduced risk of egg-shell contamination and transmission of foodborne illness. A feed additive reducing the level of Salmonella by 1 log is often viewed as a threshold of biological significance when cecal prevalence is near 100% (Hofacre, 2018Hofacre CL, Berghaus RD, Jalukar S, Mathis GF, Smith JA. Effect of a Yeast cell wall preparation on cecal and ovarian colonization with salmonella enteritidis in commercial layers. Journal of Applied Poultry Science 2018;27:4:453-460.). A previous study with the YCW product in this study showed not only a 1 log reduction in CFU/g of Salmonella than control (p<0.015), but also 20% lower prevalence (Price, 2019). A previous study with the same species of Bacillus as used in this study showed a significant reduction in the number of S. Enteritidis in layer ceca (Price, 2019b). The use of YCW as a prebiotic in layer diets and the multispecies Bacillus probiotic may decrease the level of S. Enteritidis in the ceca leading to lower contamination of the environment effectively reducing the risk of transmission of S. Enteritidis.

Figure 1
Salmonella Enteritidis predicted means in the ceca displayed as CFU/g log10 of 61 weeks of age hens challenged orally with 7 x 107 CFU/bird of Salmonella Enteritidis at 60 weeks of age. The predicted means were obtained using Tobit censored regression model left-censored at 4.477 log10 MPN/g on the 52 enrichment-positive samples. Error bars represent the SEMStandard Error of the Mean (SEM). Treatments are untreated control (Control), 500ppm Bacillus spp. probiotic (Probiotic), 500ppm Yeast cell wall (YCW), blend of Probiotic and YCW each at 250ppm (Combo).

CONCLUSIONS

The use of YCW and Probiotics in layer diets can be part of a multi-hurdle approach to reduce the load of SE in layer chickens. Reducing the load of SE in the ceca of hens reduces the total load of SE in the environment likewise reducing the risk of contamination of eggs and eggshells entering the market.

ACKNOWLEDGEMENTS

This trial was funded by Phileo by Lesaffre.

REFERENCES

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  • Afshari A, Baratpour A, Khanzade S, Jamshidi A. Salmonella enteritidis and Salmonella Typhimurium identification in poultry carcasses. Iran Journal of Microbiology 2018;10(1):45-50.
  • Alloui MN, Szczurek W, Swiatkiewicz S. The usefulness of prebiotics and probiotics in modern poultry nutrition: a review. Annals of Animal Science 2013;13:17-32
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  • Kiros T, Gaydos T, Corley J, Raspoet R, Berghaus R, Hofacre C. Effect of Saccharomyces cerevisiae yeast products in reducing direct colonization and horizontal transmission of Salmonella Heidelberg in broilers. Journal of Applied Poultry Research 2019;28:23-30.
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  • Lourenço MC, Kuritza LN, Hayashi RM, Miglino LB, Durau JF, Pickler L, et al. Effect of a mannanoligosaccharide-supplemented diet on intestinal mucosa T lymphocyte populations in chickens challenged with Salmonella Enteritidis. Journal of Applied Poultry Research. 2015;24(1):15-22.
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  • Shao Y, Guo Y, Wang Z. β-1,3/1,6-glucan alleviated intestinal mucosal barrier impairment of broiler chickens challenged with Salmonella enterica serovar Typhimurium. Poultry Science 2013;92(7):1764-1773
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  • Upadhaya SA, Hossiendoust A, Kim IH. Probiotics in Salmonella-challenged Hy-Line brown layers. Poultry Science 2016;95(8):1894-1897.
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Publication Dates

  • Publication in this collection
    09 June 2021
  • Date of issue
    2021

History

  • Received
    11 Nov 2020
  • Accepted
    28 Jan 2021
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