• YAKHAK HOEJI
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• v.21 no.3
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• pp.118-134
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• 1977

In Korea, antibiotic fermentation industries have just started budding out now. Tetracycline derivative (Pfizer, CKD), Kanamycin (Dongmyung) are produced by fermentation processes. Penicillin, erythromycin, gentamicin, rifamycin, and a few others are being planned for production within a few years by major pharmaceutical and chemical firms in Korea. Reviewing past and present activities in the antibiotic fermentation industries in Korea suggests that the prospects for antibiotics will be very bright.

• Journal of Microbiology and Biotechnology
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• v.19 no.2
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• pp.136-139
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• 2009

Avermectin and its analogs are major commercial antiparasitic agents in the fields of animal health, agriculture, and human infections. Previously, comparative transcriptome analysis between the low-producer S. avermitilis ATCC31267 and the high-producer S. avermitilis ATCC31780 using a S. avermitilis whole genome chip revealed that 50 genes were overexpressed at least two-fold higher in S. avermitilis ATCC31780. To verify the biological significance of some of the transcriptomics-guided targets, five putative regulatory genes were individually cloned under the strong-and-constitutive promoter of the Streptomyces expression vector pSE34, followed by the transformation into the low-producer S. avermitilis ATCC31267. Among the putative genes tested, three regulatory genes including SAV213, SAV3818, and SAV4023 exhibited stimulatory effects on avermectin production in S. avermitilis ATCC31267. Moreover, overexpression of SAV3818 also stimulated actinorhodin production in both S. coelicolor M145 and S. lividans TK21, implying that the SAV3818, a putative TetR-family transcriptional regulator, could be a global upregulator acting in antibiotic production in Streptomyces species.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1089-1092
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• 2004

An actinorhodin nonproducing Streptomyces lividans was converted to an actinorhodin overproducer through a single chromosomal integration of an antibiotic regulatory gene, afsR2. This strain exhibited early actinorhodin production and an average of 37.5% higher productivity than the S. lividans containing multiple copies of afsR2 plasmid in a glucose-containing liquid culture.

• KSBB Journal
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• v.9 no.4
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• pp.378-384
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• 1994

An improved method for the selective isolation of high-yielding mutant strains for the production of antifungal antibiotic KRF-001 was investigated. The mutant strain U. V 4, which produces high titer of KRF-001, was selected on the high potency agar plate after ultraviolet light irradiation. The U. V 4 strain produced 2-fold more KRF-001 than the mother strain in production media. Large scale fermentation was performed using the U. V 4 strain in 100$\ell$ fermenter. The antifungal antibiotic KRF-001 secreted into culture broth was detected by HPLC in 24hrs of fermentation.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.217-224
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• 2014

A total of 150 growing ducks were assigned to five dietary treatments to study the effect of sea tangle and charcoal (STC) supplementation on growth performance and meat characteristics in a completely randomized design. There were six replicates and five ducklings in each replication. The five dietary treatments were control, antibiotic, and 0.1%, 0.5%, and 1% STC supplemented diets. No significant differences were found on ADG, ADFI, and gain:feed among treatments in different weeks. The overall (0 to 3 weeks) ADFI decreased in antibiotic treatment (p<0.05) whereas the gain:feed increased significantly upon 1.0% STC supplementation compared to control (p<0.05). No significant variation was found in meat chemical composition except crude fat content which was high in 1.0% STC dietary group (p<0.05). Meat cholesterol was reduced in 0.1% STC group (p<0.05) compared to other dose levels while serum cholesterol was unaffected. High density lipoprotein (HDL) content was high in 1.0% STC (p<0.05) and low density lipoprotein (LDL) was low in 0.1% and 1.0% STC dietary groups (p = 0.06). No significant effect was found on the thiobarbituric acid reactive substances (TBARS) of fresh meat, whereas the TBARS value of meat preserved for 1 week was reduced significantly in STC dietary groups (p<0.05). The 0.1% STC dietary group showed an increased myristic acid (p = 0.07) content whereas, the content of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids increased in STC supplementation than antibiotic group (p<0.05). An increased concentration of omega-3 fatty acids and a reduced ratio of n-6/n-3 PUFA ratio was found upon 1.0% STC supplementation compared to antibiotic dietary group (p<0.05). Therefore, 1.0% STC dietary supplementation can be used as alternatives to antibiotics in duck production.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.11
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• pp.1634-1640
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• 2012

The objective of this study was to compare pork characteristics and to determine consumer acceptability of pork chops from antibiotic free Yorkshire crossbreds sired by Berkshire (BY), Large Black (LBY), Tamworth (TY) or Yorkshire (YY) boars and reared in hoop houses. The experiments were conducted at the North Carolina Agricultural and Technical State University (NCA&TSU) Farm in Greensboro, NC and the Cherry Research Station Center for Environmental Farming Systems (CEFS) Alternative Swine Unit in Goldsboro, NC (source of antibiotic free Yorkshire sows used at both places). Twenty-four sows were artificially inseminated at each location in each of three trials. Litters were weaned at 4 wks old, and reared within deep-bedded outdoor hoop houses. To compare pork characteristics, 104 randomly selected animals were harvested at a USDA-inspected abattoir at approximately 200 d of age. Variables measured included pH, color score, $L^*$, $a^*$, $b^*$, marbling score, drip loss, hot carcass weight, backfat thickness (BF), loin muscle area (LMA), and slice shear force. Sensory panel tests were also conducted at two time periods. The data was analyzed with GLM in SAS 9.01 including location, trial, and sire breed as fixed effects. Backfat thickness, LMA, color score and $a^*$ were different among breeding groups (p<0.05). The LBY pigs had thicker backfat and smaller LMA than the other breed types. The TY and YY had less backfat than all other breed groups. Color score was lower for YY than BY and LBY but intermediate for TY. The $a^*$ was lower for TY than other breeds except LBY which was intermediate. For one sensory panel test, YY pork was more preferred overall as well as for juiciness and texture compared to BY and LBY (p<0.05), but no impact of breed type was noted for the other test, with values similar for BY, LBY, TY and YY pork. This information may help small farmers make decisions about breed types to use for outdoor production.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.1-7
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• 1999

The strain with antibacterial activity was isolated among soil samples collected in Suwon area. The isolated strain was identified as Bacillus sp. YR-1 with respect to its morphological, cultural, and physiological characteristics. Optimal medium for the highest production of antibiotic was composed of sucrose 2.0%(w/v), peptone 2.0%(w/v) and NaCl 0.1%(w/v). The maximum production of antibiotic was shown at $35^{\circ}C$ for 48 hours with the initial pH 7.0.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2004.06a
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• pp.83-87
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• 2004

• Journal of Microbiology
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• v.37 no.2
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• pp.102-110
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• 1999

Genetic determinant for the secondary metabolism was studied in heterologous expression in Streptomyces lividans TK-24 using Streptomyces griseus ATCC 10137 as a donor strain. Chromosomal DNA of S. griseus was ligated into the high-copy number Streptomyces shuttle plasmid, pWHM3, and introduced into S. lividans TK-24. A plasmid clone with 4.3-kb BamHI DNA of S. griseus (pMJJ201) was isolated by detecting for stimulatory effect on actinorhodin production by visual inspection. The 4.3-kb BamHI DNA was cloned into pWHM3 under the control of the strong constitutive ermEp promoter in both directions (pMJJ202); ermEp promoter-mediated transcription for coding sequence reading right to left: pMJJ203; ermEp promoter-mediated transcription for coding sequence reading left to right) and reintroduced into S. lividans TK-24. The production of actinorhodin was markedly stimulated due to introduction of pMJJ202 on regeneration agar. The introduction of pMJJ202 also stimulated production of actinorhodin and undecylproidigiosin in submerged culture employing the actinorhodin production medium. Introduction of pMJJ203 resulted in a marked decrease of production of the two pigments. Nucleotide sequence analysis of the 4.3-kb region revealed three coding sequences: two coding sequences reading left to right, ORF1 and ORF2, one coding sequence reading right to left, ORF3. Therefore, it was suggested that the ORF3 product was responsible for the stimulation of antibiotic production. The C-terminal region of ORF3 product showed a local alignment with Myb-related transcriptional factors, which implicated that the ORF3 product might be a novel DNA-binding protein related to the regulation of secondary metabolism in Streptomyces.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.12
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• pp.1667-1673
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• 2017

Antibiotics have long been of great benefit for people, both in the medical treatment of human disease and in animal food where they improve the growth performance and feed utilization during animal production. Antibiotics as in-feed supplements affect all stages of pork production, including the gestation, nursing, growing, and finishing stages, although the effects show stage-dependent differences. However, the use of antibiotics in animal feed has become a worldwide concern. This review describes why sub-therapeutic levels of antibiotic additives in animal feed have become an integral part of animal feeding programs for more than 70 years, particularly in pork production. It also discusses the threat of the long-term use of sub-therapeutic levels of antibiotics in pork production. In recent years, the effectiveness of in-feed antibiotics has tended to decrease. This review analyzes this change from various perspectives. First, the equipment used at pig farms has improved dramatically and is more sanitary. Worldwide, more pig farms use pig farrowing crates, gestation crates, piglet nursery crates, flooring devices, piggery ventilation and cooler systems, automatic pig feeders, piggery heating equipment, and artificial insemination systems. In addition, scientists have replaced the use of antibiotics with organic acids, fermented mash, probiotics, prebiotics, minerals, oligosaccharides, enzymes, herbs/flavors, and protein/amino acids, and have improved management and husbandry techniques. In addition, animal welfare legislation has been aimed at improving the quality of the floors and living space, ensuring that animals have permanent access to fresh water, and setting a minimum weaning age. Finally, the prospects and the possibility of replacing antibiotics in pork production are described, in line with recent research results.