• Journal of Microbiology and Biotechnology
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• v.29 no.5
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• pp.696-703
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• 2019

Cronobacter sakazakii is an opportunistic pathogen causing serious infections in neonates. In this study, a bacteriophage ${\Phi}CS01$, which infects C. sakazakii, was isolated from swine feces and its morphology, growth parameters, and genomic analysis were investigated. Transmission electron microscopy revealed that ${\Phi}CS01$ has a spherical head and is 65.74 nm in diameter with a 98.75 nm contracted tail, suggesting that it belongs to the family Myoviridae. The major viral proteins are approximately 71 kDa and 64 kDa in size. The latent period of ${\Phi}CS01$ was shown to be 60 min, and the burst size was 90.7 pfu (plaque-forming units)/infected cell. Bacteriophage ${\Phi}CS01$ was stable at $4-60^{\circ}C$ for 1 h and lost infectivity after 1 h of heating at $70^{\circ}C$. Infectivity remained unaffected at pH 4-9 for 2 h, while the bacteriophage was inactivated at pH <3 or >10. The double-stranded ${\Phi}CS01$ DNA genome consists of 48,195 base pairs, with 75 predicted open reading frames. Phylogenetic analysis is closely related to that of the previously reported C. sakazakii phage ESP2949-1. The newly isolated ${\Phi}CS01$ shows infectivity in the host bacterium C. sakazakii, indicating that it may be a promising alternative to antibacterial agents for the removal of C. sakazakii from powdered infant formulas.

• Journal of Veterinary Science
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• v.23 no.3
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• pp.41.1-41.15
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• 2022

Background: Proliferative enteritis caused by Lawsonia intracellularis undermines the economic stability of the swine industry worldwide. The development of cost-effective animal models to study the pathophysiology of the disease will help develop strategies to counter this bacterium. Objectives: This study focused on establishing a model of gastrointestinal (GI) infection of L. intracellularis in C57BL/6 mice to evaluate the disease progression and lesions of proliferative enteropathy (PE) in murine GI tissue. Methods: We assessed the murine mucosal and cell-mediated immune responses generated in response to inoculation with L. intracellularis. Results: The mice developed characteristic lesions of the disease and shed L. intracellularis in the feces following oral inoculation with 5 × 10⁷ bacteria. An increase in L. intracellularis 16s rRNA and groEL copies in the intestine of infected mice indicated intestinal dissemination of the bacteria. The C57BL/6 mice appeared capable of modulating humoral and cell-mediated immune responses to L. intracellularis infection. Notably, the expression of genes for the vitamin B12 receptor and for secreted and membrane-bound mucins were downregulated in L. intracellularis -infected mice. Furthermore, L. intracellularis colonization of the mouse intestine was confirmed by the immunohistochemistry and western blot analyses. Conclusions: This is the first study demonstrating the contributions of bacterial chaperonin and host nutrient genes to PE using an immunocompetent mouse model. This mouse infection model may serve as a platform from which to study L. intracellularis infection and develop potential vaccination and therapeutic strategies to treat PE.

• Korean Journal of Veterinary Service
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• v.46 no.1
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• pp.35-45
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• 2023

Pathogenic Escherichia coli is the cause of a wide range of diseases in pigs, including diarrhea, edema disease, and septicemia. Diarrhea caused E. coli may result in significant economic losses, making pathogenic E. coli an important pathogen for the swine industry. This study investigated the prevalence of virulence factor genes, antimicrobial resistance phenotypes, and resistance genes in E. coli isolated from feces of piglets in Korea between 2017 and 2020. As a result, 119 pathogenic E. coli isolates were obtained from 601 fecal samples. The F4 adhesin gene and the STb enterotoxin gene were commonly present in E. coli isolated from diarrhea samples. The dominant virulotypes of isolates from diarrhea samples were STb, Stx2e, and F4:LT:STb. More than 80% of the screened isolates were resistant to ampicillin, sulfisoxazole, chloramphenicol, or tetracycline. To confirm the resistance mechanisms for β-lactam or quinolone, we investigated the genotypic factors of resistance. Each of the ceftiofur-resistant E. coli produced an extended-spectrum β-lactamase encoded by bla_CTX-M-14, bla_CTX-M-27, and bla_CTX-M-55. And all ciprofloxacin-resistant E. coli harbored mutations in quinoloneresistance-determining-regions. In addition, some of the ciprofloxacin-resistant E. coli contained the plasmid-mediated-quinolone-resistance genes such as qepA, qnrB1, or qnrD. This study has confirmed that the F4 fimbria and the STb enterotoxin are the most predominant in pathogenic E. coli isolated from piglets with diarrhea in Korea and there is a great need for responsible and prudent use of antimicrobials to treat colibacillosis.

• Journal of Animal Science and Technology
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• v.65 no.4
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• pp.856-864
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• 2023

There are a variety of microorganisms in the animal intestine, and it has been known that they play important roles in the host such as suppression of potentially pathogenic microorganisms, modulation of the gut immunity. In addition, the gut microbiota and the livestock growth performance have long been known to be related. Therefore, we evaluated the interrelation between the growth performance and the gut microbiome of the pigs from 3 different farms, with pigs of varied ages ready to be supplied to the market. When pigs reached average market weight of 118 kg, the average age of pigs in three different farms were < 180 days, about 190 days, and > 200 days, respectively. Fecal samples were collected from pigs of age of 70 days, 100 days, 130 days, and 160 days. The output data of the 16S rRNA gene sequencing by the Illumina Miseq platform was filtered and analyzed using Quantitative Insights into Microbial Ecology (QIIME)2, and the statistical analysis was performed using Statistical Analysis of Metagenomic Profiles (STAMP). The results of this study showed that the gut microbial communities shifted as pigs aged along with significant difference in the relative abundance of different phyla and genera in different age groups of pigs from each farm. Even though, there was no statistical differences among groups in terms of Chao1, the number of observed operational taxonomic units (OTUs), and the Shannon index, our results showed higher abundances of Bifidobacterium, Clostridium and Lactobacillus in the feces of pigs with rapid growth rate. These results will help us to elucidate important gut microbiota that can affect the growth performance of pigs.

• Journal of Animal Environmental Science
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• v.14 no.2
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• pp.105-112
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• 2008

This study was carried out to investigate evaporation rate of moisture per surface area and degradation rate of organic matter in full scale escalator reversing composting facility were analyzed to develope a computer program for the computation of an optimum volume of composting facility according to handling methods of swine farm, moisture levels of manure, degradation rate of organics and evaporation rate of moisture during composting. The obtained results can be followed as bellow; The temperature in full scale escalator reversing composting facility during composting reached $70^{\circ}C$ in 4 days and maintained until 11 days. Reduction rate of moisture and density was average 1.20% and 29.7%, respectively. Annual degradation rate of organic matter was 3.53%, showing lowest rate in winter as 3.23%. These seasonal degradation rate could be a factor to be considered for proper management and installation of composting facility. When computed with the amount of feces, urine, slurry and manure plus wastewater produced, the optimum volumes of composting facility for slurry and manure plus wastewater including each 95% moisture was $229m^3$ and $277m^3$, respectively, showing 21% ($48m^3$) difference.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1018-1025
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• 2016

Probiotics are considered as the best effective alternatives to antibiotics. The aim of this study was to characterize the probiotic potential of lactobacilli for use in swine farming by using in vitro evaluation methods. A total of 106 lactic acid bacterial isolates, originating from porcine feces, were first screened for the capacity to survive stresses considered important for putative probiotic strains. Sixteen isolates showed notable acid and bile resistance, antibacterial activity, and adherence to intestinal porcine epithelial cells (IPEC-1). One isolate, LR1, identified as Lactobacillus reuteri, was selected for extensive study of its probiotic and functional properties in IPEC-1 cell models. L. reuteri LR1 exhibited good adhesion to IPEC-1 cells and could inhibit the adhesion of enterotoxigenic Escherichia coli (ETEC) to IPEC-1 cells. L. reuteri LR1 could also modulate transcript and protein expression of cytokines involved in inflammation in IPEC-1 cells; the Lactobacillus strain inhibited the ETEC-induced expression of proinflammatory transcripts (IL-6 and TNF-α) and protein (IL-6), and increased the level of anti-inflammatory cytokine (IL-10). Measurement of the permeation of FD-4 showed that L. reuteri LR1 could maintain barrier integrity in monolayer IPEC-1 cells exposed to ETEC. Immunolocalization experiments showed L. reuteri LR1 could also prevent ETEC-induced tight junction ZO-1 disruption. Together, these results indicate that L. reuteri LR1 exhibits desirable probiotic properties and could be a potential probiotic for use in swine production.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.6
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• pp.992-1001
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• 2020

Objective: This study was conducted to investigate the effects of hot-melt extruded ZnO nano-particles (HME-ZnO) as an alternative for P-ZnO on growth performance, nutrient digestibility, Zn bioavailability, intestinal microbiota, and intestinal morphology of weanling pigs. Methods: A total of 450 piglets (Landrace×Yorkshire×Duroc) were randomly allotted to five treatments based on initial body weight and sex. The experimental diets were fed in a meal form as phase 1 from d 0 to 14 and phase 2 from d 15 to 28. Treatments were the control diet without ZnO supplementation, the diet containing 2,500 ppm Zn as ZnO, and three diets containing 500, 1,000, or 2,500 ppm Zn as HME-ZnO. Results: The overall result showed a higher (p<0.01) average daily gain in weanling pigs fed ZnO-supplemented diets in comparison to the control diet. There was a decrease (p<0.01) in fecal score in the ZnO-supplemented diets. Dietary supplementation of ZnO improved (p<0.05) crude protein digestibility. The weanling pigs fed the P-ZnO diet had a lower (p<0.01) Zn digestibility in the feces than HME-ZnO supplemented treatments. Weanling pigs fed diets supplemented with ZnO had greater (p<0.05) Lactobacillus spp. populations and lower Clostridium spp. (p<0.05) and Coliforms (p<0.01) populations in the ileum. Weanling pigs fed diets supplemented with increasing concentrations of HME-ZnO linearly decreased Clostridium spp. (p<0.05) and Coliforms (p<0.01) in the ileum. Lower (p<0.05) Clostridium spp. and Coliforms counts in the colon were observed in pigs fed with ZnO-supplemented diets. Weanling pigs fed diets supplemented with ZnO showed a greater (p<0.01) villus height in the duodenum. Conclusion: Dietary supplementation of HME-ZnO and P-ZnO showed a potential to improve the digestibility of protein, intestinal Coliform and Clostridium, villus height in duodenum and ileum. Moreover, HME-ZnO showed a higher Zn digestibility compared with P-ZnO.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1265-1265
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• 2001

The organic materials included in excreta of livestock are important resources for organic manure and for improving soil quality, although there is still far from effective using. One reason for this is still unclearly standard of quality for evaluation of manure made from excreta of livestock. Therefore, the objective of this study is to develop rapid and accurate analytical method for analyzing organic compositions of manure made from excreta of livestock, and to establish quality evaluation method based on the compositions predicted by near infrared reflectance spectroscopy (NIRS). Sixteen samples of manure, each eight samples prepared from two treatments, were used in this study. The manure samples were prepared by mixing 560 kg feces of swine,60 kg sawdust with moisture content was adjusted to be 65%. The mixture was then keep under two kinds of shelter, black and clear sheets, as a treatment on the effect of sunlight. Samples were taken in every week (form week-0 to 7) during the process of manure making. Samples were analyzed to determine neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) by detergent methods, and organic cell wall (OCW) and fibrous content of low digestibility in OCW (Ob) by enzymatic methods. Biological oxygen demand (BOD) was analyzed by coulometric respirometer method. These compositions were carbohydrateds and lignin that were hardly digested. Spectra of samples were scanned by NIR instrument model 6500 (Pacific Scientific) and read over the range of wavelength between 400 and 2500nm. Calibration equations were developed using eight manure samples collected from black sheet shelter, while prediction was conducted to the other eight samples from clear sheet shelter. Accuracy of NTRS prediction was evaluated by correlation coefficients (r), standard error of prediction (SEP) and ration of standard deviation of reference data in prediction sample set to SEP (RPD). The r, SEP and RPD value of forage were 0.99, 0.69 and 7.6 for ADL, 0.96, 1.03 and 4.1 for NDF, 0.98, 0.60 and 4.9 for ADF, 0.92, 1.24 and 2.6 for Ob, and 0.91, 1.02 and 7.3 for BOD, respectively. The results indicated that NIRS could be used to measure the organic composition of forage used in manure samples.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.176-181
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• 2011

Cronobacter sakazakii and Salmonella enterica Typhimurium are hazardous pathogens, especially for ready-toeat foods. For control of pathogens, the virulent bacteriophages were isolated, identified, and applied to infant formula milk and vegetable juice. The phages were isolated from swine feces and identified by morphology and molecular characteristics. ES2 phage for C. sakazakii and ST2 phage for S enterica Typhimurium were identified as Myoviridae and Siphoviridae, respectively. Their burst sizes were $52{\pm}5PFU/cell$ for ES2 phage and $21{\pm}3PFU/cell$ for ST2 phage after latent period of 30-40 minutes. ST2 phage showed higher heat stability at $60^{\circ}C$ than ES2 phage. ES2 phage held the growth of C. sakazakii untill 6 hr afterwhich the number decreased when applied to the infant formula milk and vegetable juice. ST2 phage also showed growth inhibition so that the number of S. enterica Typhimurium decreased. Therefore, virulent bacteriophages might be an agent for the growth inhibition of C. sakazakii and S. enterica Typhimurium in such the ready-to-eat foods.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.5
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• pp.662-670
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• 2015

The objectives of this study were to investigate the effects of feeding barley naturally contaminated with Fusarium mycotoxins on growth performance, vulva swelling, and digestibility of dry matter, organic matter, and crude protein of gilts and the recovery of gilts fed normal diets immediately after the exposure to contaminated diets by measuring growth performance and vulva swelling. In Exp. 1, four diets were prepared to contain 0%, 15%, 30%, or 45% contaminated barley containing 25.7 mg/kg deoxynivalenol and $26.0{\mu}g/kg$ zearalenone. Sixteen gilts with an initial body weight (BW) of 33.3 kg (standard deviation = 3.0) were individually housed in a metabolism crate and assigned to 4 diets with 4 replicates in a randomized complete block design based on BW. During the 14-d feeding trial, individual BW and feed consumption were measured weekly and the vertical and horizontal lengths of vulva were measured every 3 d. From d 10, feces were collected by the maker-to-marker method for 4 d. Blood samples were collected on d 14. During the overall period, the average daily gain, average daily feed intake, and gain:feed of pigs linearly decreased (p<0.01) as the dietary concentration of contaminated barley increased. However, the digestibility of crude protein was linearly increased (p = 0.011) with the increasing amounts of contaminated barley. Increasing dietary Fusarium mycotoxin concentrations did not influence vulva size, blood characteristic as well as immunoglobulin level of pigs. In the Exp. 2, a corn-soybean meal-based diet was formulated as a recovery diet. Pigs were fed the recovery diet immediately after completion of the Exp. 1. During the 14-d of recovery period, the individual BW and feed consumption were measured weekly and the vertical and horizontal length of vulva were measured every 3 d from d 0. On d 7, the feed intake of pigs previously fed contaminated diets already reached that of pigs fed a diet with 0% contaminated barley and no significant difference in growth performance among treatments was observed during d 7 to 14 of the recovery period. In conclusion, increasing levels of mycotoxins in diets linearly decreased the growth performance of pigs, and these damages can be recovered in 7 d after the diet was replaced with a normal diet. The vulva size, blood characteristic, immune responses were not affected by increasing level of contaminated barley in the diets fed to pigs.