• Animal Bioscience
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• v.35 no.8
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• pp.1109-1120
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• 2022

Antibiotics used to be supplemented to animal feeds as growth promoter and as an effective strategy to reduce the burden of pathogenic bacteria present in the gastro-intestinal tract. However, in-feed antibiotics also kill bacteria that may be beneficial to the animal. Secondly, unrestricted use of antibiotics enhanced the antibiotic resistance in pathogenic bacteria. To overcome above problems, scientists are taking a great deal of measures to develop alternatives of antibiotics. There is convincing evidence that probiotics could replace in-feed antibiotics in poultry production. Because they have beneficial effects on growth performance, meat quality, bone health and eggshell quality in poultry. Better immune responses, healthier intestinal microflora and morphology which help the birds to resist against disease attack were also identified with the supplementation of probiotics. Probiotics establish cross-feeding between different bacterial strains of gut ecosystem and reduce the blood cholesterol level via bile salt hydrolase activity. The action mode of probiotics was also updated according to recently published literatures, i.e antimicrobial substances generation or toxin reduction. This comprehensive review of probiotics is aimed to highlight the beneficial effects of probiotics as a potential alternative strategy to replace the antibiotics in poultry.

• Journal of Veterinary Science
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• v.25 no.2
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• pp.33.1-33.11
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• 2024

Agricultural production is a major driver of the Philippine economy. Mass production of animal products, such as livestock and poultry farming, is one of the most prominent players in the field. Filipino farmers use veterinary medicinal products (VMPs) when raising agricultural animals to improve animal growth and prevent diseases. Unfortunately, the extensive use of VMPs, particularly antibiotics, has been linked to drug resistance in animals, particularly antibiotics. Antimicrobial gene products produced in animals due to the prolonged use of VMPs can passed on to humans when they consume animal products. This paper reviews information on the use of VMPs in the Philippines, including the regulations, their impact, challenges, and potential recommendations. The Philippines has existing legislation regulating VMP use. Several agencies were tasked to regulate the use of VMPs, such as the Department of Agriculture, the Department of Health, and the Philippine National Action Plan. Unfortunately, there is a challenge to implementing these regulations, which affects consumers. The unregulated use of VMPs influences the transmission of antibiotic residues from animals to crops to humans. This challenge should be addressed, with more focus on stricter regulation.

• KSBB Journal
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• v.14 no.6
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• pp.682-687
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• 1999

Virginiae butanolide C(VB-C) is one of the butyrolactone autoregulators, which triggers the production of virginiamycin in Streptomyces virginiae. In order to investigate the function of VB-C as inducer in other strains, Streptomyces erythraeus was used as a test strain(parent). VB-C binding receptor gene was introduced into S. erythraeus(transformant) and the production of VBs and specific VB-C binding protein were analysed in parent and transformant. When 300ng/ml of the synthetic VB-C was added at 0, 20, 44 h cultivation of the parent and at 44 h cultivation of the transformant, the initial production times a antibiotics were shortened by more than 8 and 6 h, respectively. The transformant showed strong antibiotic activity against B. subtilis. These results suggest that the VB-C might have an ability to induce the production of secondary metabolites in S. erythraeus.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.694-698
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• 2007

Berberine, an alkaloid initially isolated from chinese herbal medicine, has antibiotic activities against a variety of organisms including bacteria, viruses, fungi, protozoans, and chlamydia. Furthermore, berberine has shown a number of beneficial effects, including anti-tumor, anti-inflammation, and vasodilatory effects. In this work we have investigated the effects of berberine on lymphocyte proliferation and GM-CSF production in mice. Mouse splenocytes were incubated with berberine and concanavalin A(Con A) to observe the effects on cell proliferation. The culture supernatants of splenocytes exposed to berberine, berberine plus LPS, and berberine plus Con A were harvested to assay GM-CSF. The cell proliferation of nice splenocytes exposed to berberine only($1{\mu}g/ml$) was increased significantly more than PBS(control) group. But the Con A-induced cell growth was inhibited by berberine. The GM-CSF production from mice splenocyte culture exposed to berberine only was increased in comparison with PBS(control) group, but the production of it with LPS or Con A was inhibited by berbeline. The present findings may explain lympocyte proliferating and regulating effects of berberine.

• Animal Bioscience
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• v.35 no.1
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• pp.138-146
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• 2022

Objective: The objective of the current study was to investigate the influences of conventional (CO) and deep litter (DE) systems on antimicrobial resistance in fecal Escherichia coli (E. coli). Methods: A cross-sectional study was carried out to detect antimicrobial resistance to E. coli in swine fecal samples in CO and DE systems located in western and northeastern Thailand. Individual rectal swab samples were taken only from healthy pigs. A total of 215 individual and healthy pigs were randomly selected for isolation and antimicrobial susceptibility test of E. coli by the disc diffusion method. The test panel included amoxicillin (AMX), colistin, doxycycline (DOX), enrofloxacin, gentamicin (GEN), kanamycin, neomycin (NEO), and trimethoprim-sulfamethoxazole (SXT). Results: There were significant (p<0.05) lower resistance levels for GEN, NEO, and SXT in the DE farms compared to those in the CO farms. There was a lower number of antimicrobial resistance agents (p<0.001) in the DE farms compared to those in the CO farms. This result was consistent with those in western (p<0.01) and northeastern (p<0.01) Thailand. Overall, antibiograms of AMX-SXT and AMX-DOX-SXT were found in the CO (19.09% and 20.91%, respectively) and the DE (16.19% and 24.76%, respectively) farms. No antimicrobial resistance (5.71%) was found and AMX (13.33%) resistant pigs in the DE farms, whereas the pattern of AMX-GEN-SXT (6.36%) and AMX-DOX-GEN-SXT (11.82%) resistant pigs was found in the CO farms. Conclusion: The DE system for pig farming was superior to conventional pig farming by lowering the resistance level of fecal E. coli to GEN, NEO, and SXT, with decreasing the number of antimicrobial resistance agents and inducing a small proportion of pigs to be free from antimicrobial resistance.

• Journal of Pharmacopuncture
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• v.26 no.4
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• pp.307-318
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• 2023

Objectives: Bacterial biofilm is regarded as a significant threat to the production of safe food and the arise of antibiotic-resistant bacteria. The objective of this investigation is to evaluate the quorum sensing inhibitory effect of Nepeta curviflora methanolic extract. Methods: The effectiveness of the leaves at sub-inhibitory concentrations of 2.5, 1.25, and 0.6 mg/mL on the virulence factors and biofilm formation of P. aeruginosa was evaluated. The effect of N. curviflora methanolic extract on the virulence factors of P. aeruginosa, including pyocyanin, rhamnolipid, protease, and chitinase, was evaluated. Other tests including the crystal violet assay, scanning electron microscopy (SEM), swarming motility, aggregation ability, hydrophobicity and exopolysaccharide production were conducted to assess the effect of the extract on the formation of biofilm. Insight into the mode of antiquorum sensing action was evaluated by examining the effect of the extract on the activity of N-Acyl homoserine lactone (AHL) and the expression of pslA and pelA genes. Results: The results showed a significant attenuation in the production of pyocyanin and rhamnolipid and in the activities of protease and chitinase enzymes at 2.5 and 1.25 mg/mL. In addition, N. curviflora methanolic extract significantly inhibited the formation of P. aeruginosa biofilm by decreasing aggregation, hydrophobicity, and swarming motility as well as the production of exopolysaccharide (EPS). A significant reduction in AHL secretion and pslA gene expression was observed, indicating that the extract inhibited quorum sensing by disrupting the quorum-sensing systems. The quorum-sensing inhibitory effect of N. curviflora extract appears to be attributed to the presence of kaempferol, quercetin, salicylic acid, rutin, and rosmarinic acid, as indicated by LCMS analysis. Conclusion: The results of the present study provide insight into the potential of developing anti-quorum sensing agents using the extract and the identified compounds to treat infections resulting from quorum sensing-mediated bacterial pathogenesis.

• Mycobiology
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• v.40 no.1
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• pp.59-65
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• 2012

Antagonistic microorganisms against $Rhizoctonia$ $solani$ were isolated and their antifungal activities were investigated. Two hundred sixteen bacterial isolates were isolated from various soil samples and 19 isolates were found to antagonize the selected plant pathogenic fungi with varying degrees. Among them, isolate C9 was selected as an antagonistic microorganism with potential for use in further studies. Treatment with the selected isolate C9 resulted in significantly reduced incidence of stem-segment colonization by $R.$ $solani$ AG2-2(IV) in Zoysia grass and enhanced growth of grass. Through its biochemical, physiological, and 16S rDNA characteristics, the selected bacterium was identified as $Bacillus$ $subtilis$ subsp. $subtilis$. Mannitol (1%) and soytone (1%) were found to be the best carbon and nitrogen sources, respectively, for use in antibiotic production. An antibiotic compound, designated as DG4, was separated and purified from ethyl acetate extract of the culture broth of isolate C9. On the basis of spectral data, including proton nuclear magneric resonance ($^1H$ NMR), carbon nuclear magneric resonance ($^{13}C$ NMR), and mass analyses, its chemical structure was established as a stereoisomer of acetylbutanediol. Application of the ethyl acetate extract of isolate C9 to several plant pathogens resulted in dose-dependent inhibition. Treatment with the purified compound (an isomer of acetylbuanediol) resulted in significantly inhibited growth of tested pathogens. The cell free culture supernatant of isolate C9 showed a chitinase effect on chitin medium. Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.5
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• pp.643-649
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• 2011

The objective of this study was to determine the effect of feeding direct-fed microbials (DFM) on the growth performance and prophylaxis of calf diarrhea during the pre-weaning period as an alternative to antibiotics. A multi-species DFM was formulated including three lactic acid bacteria (Lactobacillus salivarius Ls29, Pediococcus acidilactia Pa175, and L. plantarum Lp177), three Bacillus strains (B. subtilis T4, B. polymyxa T1 and SM2), one yeast, Saccharomyces boulardii, and a nonpathogenic E. coli Nissle 1917. Lactic acid bacteria and Bacillus strains were selected based on the antibacterial activity against various animal pathogens, especially pathogenic E. coli using agar diffusion methods in vitro. Test and control groups were fed milk replacer and calf starter supplemented with DFM ($10^9$ cfu each of eight species/d/head, n = 29) or with antibiotics (0.1% neomycin sulfate in milk replacer and Colistin 0.08% and Oxyneo 110/110 0.1% in calf starter, n = 15), respectively. Overall fecal score and the incidence rate of diarrhea were reduced in the DFM group compared to the antibiotics one. About 40% of calves in antibiotic group suffered from diarrhea while in DFM group only 14% showed diarrhea. There was no difference in the average daily gain and feed efficiency of two groups. The hematological levels of calves were all within the normal range with no significant difference. In conclusion, the feeding of multispecies DFM during the pre-weaning period could reduce calf diarrhea and there was no difference in the growth performance between the groups, thus showing the potential as an alternative to antibiotics.

• Food Science of Animal Resources
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• v.35 no.4
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• pp.502-506
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• 2015

The aim of this study was to investigate the antimicrobial resistance profiles of and the enterotoxin gene distribution in 4 strains of Staphylococcus aureus (S10-2, S10-3, S12-2, and S13-2) isolated from 90 bulgogi samples. The S. aureus enterotoxin H gene (seh) was found in all the strains, while the S. aureus enterotoxin A gene (sea) was found only in 3 of the 4 strains. The S10-2 strain expressed a combination of enterotoxin genes - seg, seh, sei, sej, selm, and seln. The strains S10-2 and S13-2 were resistant to ampicillin and penicillin G, and all the isolated strains were resistant to tetracycline. The S10-2 strain was the only mecA-positive strain; it was also resistant to β-lactam antibiotics. Thus, genes encoding enterotoxin as well as those conferring antibiotic resistance were identified in the S. aureus strains isolated from pork bulgogi. These results represents the potential occurrence of MRSA in pork bulgogi, and the need for a monitoring system for pork bulgogi in order to prevent an outbreak of staphylococcal food poisoning.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.384-390
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• 2009

An antifungal antibiotic-producing bacterium was isolated from soil and identified as Bacillus sp. CJ-1. The culture supernatant was found to have a strong and stable antifungal activity against Colletotrichum gloeosporioides. Culture conditions for the maximum antifungal activity were examined. Glucose and yeast extract were selected as the best carbon and nitrogen sources. The optimum C/N ratio was 3. The optimum temperature and initial pH were determined as $35^{\circ}C$ and 6.0, respectively. Under these conditions, the production for the antibiotic was maximized at 72 hr at $35^{\circ}C$ after cultivation. Microscopic observation showed that the culture supernatant of Bacillus sp. CJ-1 had a strong inhibitory activity on the mycelial growth of the test strain at above $12.5\;{\mu}L\;mL^{-1}$ of concentration.