• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
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• pp.416-417
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• 2000

Chitin, a poly $\beta$-(1longrightarrow14)-N-acetyl-D-glucosamine, is best known as a cell wall component of fungi and as a skeletal materials of invertebrates. Chitosan is derived from chitin by deacetylation in the presence of alkali. Chitosan has been developed as new physiological materials since it possesses antibacterial activity, hypocholesterolemic activity and antihypertensive action. However, the actions of chitosan in vivo still remain ambiguous as the physiological functional properties because most animal intestines, especially the human gastrointestinal tract, do not possess enzyme such as chitosanase which directly degrade the $\beta$-glucosidic linkage in chitosan, and consequently the unbroken polymers may be poorly absorbed into the human intestine. Therefore, recent studies as chitosan have attracted interest for chitosan oligosaccharides, because the oligosaccharides process not only water-soluble property but also versatile functional properties such as antitumor activity, immune-enhancing effects, enhancement of protective effects against infection with some pathogens in mice and antimicrobial activity (Kingsnorth et al., 1983, Mori et al., 1997). (omitted)

• Journal of Dairy Science and Biotechnology
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• 제32권2호
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• pp.141-145
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• 2014

시장에는 프로바이오틱스를 포함한 무수히 많은 제품이 판매되고 있는데, 우리에게 어떤 이로운 점을 줄 수 있는지 궁금해 한 적이 있었을 것이다. 프로바이오틱스는 기본적인 영양 측면을 배제하고, 우리가 유효한 양을 섭취하였을 때 건강상의 이점을 주는 살아있는 미생물로 정의된다. 프로바이오틱스는 유용하고 건강에 좋은 미생물로도 불려지고 있으며, 다음과 같은 다섯 가지 측면에서 건강 기능성이 있는 것으로 강조되어 왔는데, 1) 대장암 및 IBS와 같은 다른 대장(결장)관련 질병의 발병율 감소, 2) 면역 시스템의 촉진, 3) 항고혈압 및 항콜레스테롤 작용, 4) 장내세균에 작용하는 항생제의 효과를 경감시키고, 5) 위장관 감염을 예방시키는 점이다. 그러나 이러한 건강기능 작용들에 대한 과학적인 근거가 충분히 구축되어 있지는 않아, 유럽식품 위생위원회(Euroupe Food Safety Authority)는 항생제 투여에 따른 설사증상의 완화와 같은 건강기능 표시를 금지하고 있어, 프로바이오틱스의 작용기전에 대한 연구가 필요한 시점이라 하겠다.

• Toxicological Research
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• 제26권4호
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• pp.301-313
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• 2010

Growth promoters including hormonal substances and antibiotics are used legally and illegally in food producing animals for the growth promotion of livestock animals. Hormonal substances still under debate in terms of their human health impacts are estradiol-$17\beta$, progesterone, testosterone, zeranol, trenbolone, and melengestrol acetate (MGA). Many of the risk assessment results of natural steroid hormones have presented negligible impacts when they are used under good veterinary practices. For synthetic hormonelike substances, ADIs and MRLs have been established for food safety along with the approval of animal treatment. Small amounts of antibiotics added to feedstuff present growth promotion effects via the prevention of infectious diseases at doses lower than therapeutic dose. The induction of antimicrobial resistant bacteria and the disruption of normal human intestinal flora are major concerns in terms of human health impact. Regulatory guidance such as ADIs and MRLs fully reflect the impact on human gastrointestinal microflora. However, before deciding on any risk management options, risk assessments of antimicrobial resistance require large-scale evidence regarding the relationship between antimicrobial use in food-producing animals and the occurrence of antimicrobial resistance in human pathogens. In this article, the risk profiles of hormonal and antibacterial growth promoters are provided based on recent toxicity and human exposure information, and recommendations for risk management to prevent human health impacts by the use of growth promoters are also presented.

• Journal of Dairy Science and Biotechnology
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• 제34권2호
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• pp.75-82
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• 2016

Members of the genus Bifidobacterium are prevalent in the human colon and represent up to 90% of all bacteria in fecal samples of breast-fed infants, and 3~5% of adult fecal microbiota. Bifidobacteria produce organic acids, thus reducing the colon pH to a level inhibitory for pathogenic bacteria. They can also detoxify a number of toxic compounds and adhere to the colon mucosa, thus preventing the adherence of pathogens and induction of colon cancer. Recently, we identified a novel Bifidobacterium longum subsp. longum strain, KACC 91563, in a fecal sample of a Korean neonate, and demonstrated its functional properties. We showed that B. longum KACC 91563 alleviates food allergy through mast cell suppression and produces antioxidative and antihypertensive peptides by casein hydrolysis. Dairy products are considered as an ideal food system for the delivery of probiotic cultures to the human gastrointestinal tract. Cheese affords protection to probiotic microbes during gastric transit due to its relatively high pH, more solid consistency, higher fat content, and higher buffering capacity. Incorporation of B. longum KACC 91563 into cheese making is currently under study.

• Biomolecules & Therapeutics
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• 제29권4호
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• pp.353-364
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• 2021

The gastrointestinal (GI) tract is a series of hollow organs that is responsible for the digestion and absorption of ingested foods and the excretion of waste. Any changes in the GI tract can lead to GI disorders. GI disorders are highly prevalent in the population and account for substantial morbidity, mortality, and healthcare utilization. GI disorders can be functional, or organic with structural changes. Functional GI disorders include functional dyspepsia and irritable bowel syndrome. Organic GI disorders include inflammation of the GI tract due to chronic infection, drugs, trauma, and other causes. Recent studies have highlighted a new explanatory mechanism for GI disorders. It has been suggested that autophagy, an intracellular homeostatic mechanism, also plays an important role in the pathogenesis of GI disorders. Autophagy has three primary forms: macroautophagy, microautophagy, and chaperone-mediated autophagy. It may affect intestinal homeostasis, host defense against intestinal pathogens, regulation of the gut microbiota, and innate and adaptive immunity. Drugs targeting autophagy could, therefore, have therapeutic potential for treating GI disorders. In this review, we provide an overview of current understanding regarding the evidence for autophagy in GI diseases and updates on potential treatments, including drugs and complementary and alternative medicines.

• Journal of Animal Science and Technology
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• 제64권4호
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• pp.671-695
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• 2022

The gastrointestinal tract is a complex ecosystem that contains a large number of microorganisms with different metabolic capacities. Modulation of the gut microbiome can improve the growth and promote health in pigs. Crosstalk between the host, diet, and the gut microbiome can influence the health of the host, potentially through the production of several metabolites with various functions. Short-chain and branched-chain fatty acids, secondary bile acids, polyamines, indoles, and phenolic compounds are metabolites produced by the gut microbiome. The gut microbiome can also produce neurotransmitters (such as γ-aminobutyric acid, catecholamines, and serotonin), their precursors, and vitamins. Several studies in pigs have demonstrated the importance of the gut microbiome and its metabolites in improving growth performance and feed efficiency, alleviating stress, and providing protection from pathogens. The use of probiotics is one of the strategies employed to target the gut microbiome of pigs. Promising results have been published on the use of probiotics in optimizing pig production. This review focuses on the role of gut microbiome-derived metabolites in the performance of pigs and the effects of probiotics on altering the levels of these metabolites.

• Asian-Australasian Journal of Animal Sciences
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• 제23권12호
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• pp.1657-1667
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• 2010

Direct-fed microbials (DFM) are dietary supplements that inhibit gastrointestinal infection and provide optimally regulated microbial environments in the digestive tract. As the use of antibiotics in ruminant feeds has been banned, DFM have been emphasized as antimicrobial replacements. Microorganisms that are used in DFM for ruminants may be classified as lactic acid producing bacteria (LAB), lactic acid utilizing bacteria (LUB), or other microorganisms including species of Lactobacillus, Bifidobacterium, Enterococcus, Streptococcus, Bacillus and Propionibacterium, strains of Megasphaera elsdenii and Prevotella bryantii and yeast products containing Saccharomyces and Aspergillus. LAB may have beneficial effects in the intestinal tract and rumen. Both LAB and LUB potentially moderate rumen conditions and improve feed efficiency. Yeast DFM may reduce harmful oxygen, prevent excess lactate production, increase feed digestibility, and improve fermentation in the rumen. DFM may also compete with and inhibit the growth of pathogens, stimulate immune function, and modulate microbial balance in the gastrointestinal tract. LAB may regulate the incidence of diarrhea, and improve weight gain and feed efficiency. LUB improved weight gain in calves. DFM has been reported to improve dry matter intake, milk yield, fat corrected milk yield and milk fat content in mature animals. However, contradictory reports about the effects of DFM, dosages, feeding times and frequencies, strains of DFM, and effects on different animal conditions are available. Cultivation and preparation of ready-to-use strict anaerobes as DFM may be cost-prohibitive, and dosing methods, such as drenching, that are required for anaerobic DFM are unlikely to be acceptable as general on-farm practice. Aero-tolerant rumen microorganisms are limited to only few species, although the potential isolation and utilization of aero-tolerant ruminal strains as DFM has been reported. Spore forming bacteria are characterized by convenience of preparation and effectiveness of DFM delivery to target organs and therefore have been proposed as DFM strains. Recent studies have supported the positive effects of DFM on ruminant performance.

• 한국가금학회지
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• 제45권1호
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• pp.1-15
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• 2018

Salmonella infections in livestock industry cause various problems such as worsening animal welfare and productivity, damaging consumer confidence in the food safety of animal products. Chicken meat and eggs are known as major source of pathogen causing human foodborne infections. Therefore food safety concerns have prompted the poultry producers and governments to introduce the strategy and regulation to control these pathogens. Salmonella can persist for long periods of time in a wide range of spaces including feed bin, feed processing facilities, poultry farm, slaughterhouse, processing plants, etc. For the effective and constant Salmonella control, combination of pre-harvest, harvest and post-harvest measures should be considered comprehensively. The control measures would be most effective at farm level where the contamination initiates. Transmission of pathogen from feed origin to the live poultry and finally to the products was proven already. To control bacteria in the feed ingredients and formula feed, thermal processing, irradiation or chemical treatment may be applied. Chemical treatments to inhibit Salmonella in the feed involve the use of products containing organic acids, formaldehyde, or a combination of such compounds. However, recontamination which might occur during storage and transport process and/or by other various factors should always be under control and eliminated. Feed additives used to control Salmonella in birds' gastrointestinal track can be of various types, including prebiotics, probiotics, organic acids and bacteriophages. Although their mode of action varies, they ultimately inhibit the colonization of Salmonella in the gut and improve the performance of birds. This review describes the strategies that could be adapted to the management of feedstuffs and the use of feed additives in pre-harvest stage to control Salmonella contamination in poultry farming.

• Journal of Microbiology and Biotechnology
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• 제25권7호
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• pp.1084-1092
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• 2015

In the present work, the in vitro prebiotic activity of xylooligosaccharides (XOS) derived from corn cobs combined with Lactobacillus plantarum, a probiotic microorganism, was determined. These probiotics exhibited different growth characteristics depending on strain specificity. L. plantarum S2 cells were denser and their growth rates were higher when cultured on XOS. Acetate was found to be the major short-chain fatty acid produced as the end-product of fermentation, and its amount varied from 1.50 to 1.78 mg/ml. The antimicrobial activity of XOS combined with L. plantarum S2 was determined against gastrointestinal pathogens. The results showed that XOS proved to be an effective substrate, enhancing antimicrobial activity for L. plantarum S2. In vivo evaluation of the influence of XOS and L. plantarum S2, used both alone and together, on the intestinal microbiota in a mouse model showed that XOS combined with L. plantarum S2 could increase the viable lactobacilli and bifidobacteria in mice feces and decrease the viable Enterococcus, Enterobacter, and Clostridia spp. Furthermore, in the in vitro antioxidant assay, XOS combined with L. plantarum S2 possessed significant 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis, and superoxide anion radical-scavenging activities, and the combinations showed better antioxidant activity than either XOS or L. plantarum S2 alone.

• 농업과학연구
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• 제45권4호
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• pp.655-663
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• 2018

The insect gut microbiome is known to have important roles in host growth, development, digestion, and resistance against pathogens. In addition, the genetic diversity of the insect gut microbiota has recently been recognized as potential genetic resources for industrial bioprocessing. However, there is limited information regarding the insect gut microbiota to better help us understand their potential benefits for enhanced pig production. With the development of next-generation sequencing methods, whole genome sequence analysis has become possible beyond traditional culture-independent methods. This improvement makes it possible to identify and characterize bacteria that are not cultured and located in various environments including the gastrointestinal tract. Insect intestinal microorganisms are known to have an important role in host growth, digestion, and immunity. These gut microbiota have recently been recognized as potential genetic resources for livestock farming which is using the functions of living organisms to integrate them into animal science. The purpose of this literature review is to emphasize the necessity of research on insect gut microbiota and their applicability to pig production or bioindustry. In conclusion, bacterial metabolism of feed in the gut is often significant for the nutrition intake of animals, and the insect gut microbiome has potential to be used as feed additives for enhanced pig performance. The exploration of the structure and function of the insect gut microbiota needs further investigation for their potential use in the swine industry particularly for the improvement of growth performance and overall health status of pigs.