• Asian-Australasian Journal of Animal Sciences
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• 제23권6호
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• pp.825-832
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• 2010

The United Nations Convention on Biological Diversity defines biotechnology as "Any technological application that uses biological systems, dead organisms, or derivatives thereof, to make or modify products or processes for specific use" Biotechnology has made tremendous contributions to improve production efficiency of agriculture during the last century. This article reviews successful examples of application of bio-fermentation in improving swine nutrition efficiency mainly based on the authors'z own research experience. Production of feed grade supplemental amino acids by bio-fermentation allowed nutritionists to formulate accurate feed for optimal lean growth and reduced nitrogen excretion. Recent issues with high feed grain prices caused potential feed quality problems. Bio-fermentation allowed nutritionists to use exogenous supplemental enzymes such as phytase and NSPases in swine diets, thereby improving nutrient utilization and reducing nutrient excretion to the environment. Yeast metabolites are also produced by bio-fermentation and have been repeatedly shown to improve milk production of sows during early lactation even though actual mechanisms are still to be investigated. Bio-fermentation technology also allowed nutritionists to prepare vegetable protein sources with large protein molecules and anti-nutritional factors suitable for feeding newly weaned piglets, as selected microorganisms significantly reduce specific anti-nutritional factors and size of peptides. Preparations of vegetable protein sources suitable for newly weaned pigs will greatly contribute to swine nutrition by providing efficient alternatives to the use of animal protein sources that are often expensive and somewhat against societal preference. Considering the few examples listed above, biotechnology has closely influenced improvement of production efficiency in the swine industry. As we have limited resources to produce meat to satisfy ever-increasing global demands, extensive adaptation of biotechnology to enhance production efficiency should be continued. However, at the same time, wise and careful application of bio-technology should be considered to ensure production of safe food and to meet the expectations of our society.

• 농업과학연구
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• 제49권3호
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• pp.463-481
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• 2022

Phosphorous (P) is considered to be one of the key essential elements demanded by crop plants. Approximately 70 - 90% of phosphatic fertilizers applied to crops are fixed in soil as Ca, Fe, and Al metal cations, which are insoluble and thus not readily available for plant uptake. Therefore, most soils are deficient in plant available P. This is usually rectified by applying phosphate fertilizers continuously, although this is not economically viable or environmentally acceptable. The present paper reviews the mechanisms involved with phosphate solubilization and mineralization by phosphate solubilizing microorganisms (PSMs) with the associated factors that determine the success. PSMs are effectively involved in mediating the bioavailability of soil P. Their contribution includes mineralization of organic P solubilization of inorganic P minerals, and storing sizable amounts of P in biomass through different mechanisms such as the production of organic and inorganic acids, H₂S, siderophores, exopolysaccharides, and production of enzymes such as phosphatases, phytase, and phosphonatases/C-P lyases, which are capable of chelating the metal ions, forming complexes, and making plant available P. PSMs manifest a wide range of metabolic functions in different environments, resulting in significantly higher plant growth, enhanced soil properties, and increased biological activities. Therefore, development of bio-inoculants with efficient novel PSM strains and further investigations on exploring such strains from diverse ecological niches with multifunctional plant-growth-promoting traits are needed.

• The Plant Pathology Journal
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• 제24권2호
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• pp.143-151
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• 2008

To define the functions of the rpf genes in Xanthomonas oryzae pv. oryzae (Xoo), which regulates pathogenicity factors in Xanthomonas campestris pv. campestris (Xcc), marker-exchange mutants of each rpf gene were generated. When the mutants were inoculated on a susceptible cultivar, the lesion lengths caused by the rpfB, rpfC, rpfF, and rpfG mutants were significantly smaller than those caused by the wild type, whereas those caused by the rpfA, rpfD, and rpfI mutants were not. Several virulence determinants, including extracellular polysaccharide (EPS) production, xylanase production, and motility, were significantly decreased in the four mutants. However, the cellulase activity in the mutants was unchanged. Complementation of the rpfB and rpfC mutations restored the virulence and the expression of the virulence determinants. Expression analysis of 14 virulence genes revealed that the expression of genes related to EPS production (gumG and gumM), LPS (xanA, xanB, wxoD, and wxoC), phytase (phyA), xylanase (xynB), lipase (lipA), and motility (pitA) were reduced significantly in the mutants rpfB, rpfC, rpfF, and rpfG. In contrast, the expression of genes related to cellulase (eglxob, clsA), cellobiosidase (cbsA), and iron metabolism (fur) was unchanged. The results of this study clearly show that rpfB, rpfC, rpfF, and rpfG are important for the virulence of Xoo KACC10859, and that virulence genes are regulated differently by the Rpfs.

• Asian-Australasian Journal of Animal Sciences
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• 제16권6호
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• pp.903-909
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• 2003

For the last two decades, energy utilization of growing chicks has been studied more and more. This paper focuses on the energy utilization estimated by the metabolizable energy (ME) values and the efficiency at which ME is used for growth of chicks under various nutritional environment. Degree of saturation of dietary fats is responsible for nitrogen-corrected apparent metabolizable energy (AMEn) of fats. The effect of dietary fat sources on heat production depends on the kind of unsaturated fatty acids as well as the degree of saturation. Medium chain triglyceride shows lower AME and net energy than long chain triglyceride. Phytase as feed additives increases the AME values of the diet along with improvement of the phosphorous utilization. Ostriches have higher ability to metabolize the energy of fiber-rich foodstuffs than fowls. Their higher ability seems to be associated with fermentation of fiber in the hindgut. Proportions of macronutrients in the diets have influenced not only the gain of body protein and energy but also the oxidative phosphorylation of the chicken liver. Essential amino acids deficiency reduces ME/GE (energy metabolizability) little, if any. Growing chicks respond to a deficiency of single essential amino acids with the reduction of energy retained as protein and increased energy retained as fat. Thus, energy retention is proportional to ME intake despite deficiency, and efficiency of ME utilization is not affected by deficiency of amino acids. Effect of oral administration of clenbuterol, a beta-adrenergic agonist, on the utilization of ME varies with the dose of the agents. Although the heat production related to eating behavior has been estimated less than 5% of ME, tube-feeding diets decreases HI by about 30%.

• Asian-Australasian Journal of Animal Sciences
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• 제11권6호
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• pp.755-768
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• 1998

Nitrogen and phosphorus are major nutrients in animal feeds which partially remain in the environment as pollution. In addition, nitrogen and phosphorus along with energy are the main nutrients which determine the feed cost. Any decreases in the levels of these three nutrients can contribute to reducing the pollution problem as well as the cost of feed. The nutrient requirements for chickens in the work here reported should allow for the addition of mixed enzymes (phytases, proteases, glucanases, xylanases and others). Such minimal levels of crude protein in the research results which are here reported are 16% for 0-6 weeks of age, 13.5% for 7-12 weeks of age, 11.5% for 13-18 weeks of age for layer type chicks, 13% for layer, 18% for 0-3 weeks of age broiler and 16.5% for 4-7 weeks of age broiler. These research projects have been done without adding enzyme supplements to their experimental diets. The minimal values of phosphorus, shown as available phosphorus, are 0.25% for pullets, 0.09% for layers and 0.25% for broilers with the addition of phytase. The minimum energy requirement (metabolizable energy) for reducing the feed cost could be summarized as 2,750 kcal per kg feed for pullets, 2,800 kcal for layers and 2,700 kcal for broilers.

• 한국축산식품학회지
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• 제27권3호
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• pp.363-370
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• 2007

김치의 L. plantarum의 생균제적 특성을 조사하기 위하여 김치에서 산생산과 성장능력 등이 우수한 25종의 Lactobacillus sp.를 분리하였고, API kit 분석에 의하여 L. plantarum을 동정하고 재차 16S rDNA 염기서열(99.9% 상동성)을 비교한 후 L. plantarum JK-01로 표기하였다. L. plantarum JK-01은 MRS broth에서 배양시 18시간 후 $2.9{\times}10^{10}CFU/ml$로 최대로 증식하는 빠른 성장특성을 나타냈으며 pH도 4.5로 조속히 하강하였다. 효소활성은 xylanase, amylase, protease, phytase의 순으로 높은 활성을 포함하고 있는 것으로 예측되었다. L. plantarum JK-01은 pH 2에서도 $1.36{\times}10^5CFU/mL$가 생존하였고, 1%의 담즙산에서도 약 $10^6CFU/mL$이상이 생존하여 내산성과 내담즙산성이 강한 것으로 나타났다. 또, $60^{\circ}C$에서도 $3.3{\times}10^3$ CFU/mL 정도로 생존하는 내열성이 있었으며, 대장균과 함께 배양시 18시간 후 대장균을 사멸시키는 것으로 나타났다. 이상의 결과로부터 분리한 L. plantarum JK-01은 생균제로서 충분히 이용가치가 있는 것으로 사료되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권2호
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• pp.231-236
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• 2001

This study was conducted to investigate the effect of supplemented enzyme complex on growth performance and nutrient digestibility in pigs weaned at 14 days of age. Eighty pigs ($4.02{\pm}0.11kg$ of average body weight) were allotted in a completely randomized block design. Treatments were as follows: 1) control (negative), 2) control (positive, $Kemzyme^{(R)}$), 3) 0.1%, 4) 0.2% and 5) 0.3% of newly developed enzyme complex. Each treatment has 4 replicates with 4 pigs per replicate. During phase I period (d 0 to 14), ADG and ADFI were numerically higher in pigs fed diets supplemented enzyme complex regardless of their inclusion levels compared to pigs fed control (negative) diet. Feed/gain (F/G) was also better in pigs fed enzyme complex diet than that of pigs fed control (negative) diet. In addition, with increasing the inclusion level of enzyme complex, ADG and ADFI were improved. However, there was no significant difference between treatment in all growth parameters. During phase II period (d 15 to 28), ADG, ADFI and F/G showed the same tendency as in phase I period. For overall period (d 0 to 28) ADG was highest in pigs fed diet included 0.2% enzyme complex in all treatments but not significantly different. During phase I period, the digestibilities of all nutrients did not showed any significant difference between treatments. However, pigs fed diet contained enzyme complex and positive control diet (Kemzyme) showed numerically higher nutrient digestibilities in all nutrients than pigs fed negative control diet. During phase II period, data were consistent with those observed in phase I period. Especially, the digestibility of phosphorus was significantly higher in pigs fed diets contained enzyme complex including phytase than pigs fed control (negative and positive) diets (p<0.05). For overall experimental period, fecal or ileal amino acid digestibility were not affected by dietary treatment. Enzyme complex newly developed and used in this study can be possibly recommended as a growth promoter when supplemented in diet for early weaned piglets.