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Effect of Microbial Phytase on Performance, Nutrient Absorption and Excretion in Weaned Pigs and Apparent Ileal Nutrient Digestibility in Growing Pigs

  • Zeng, Z.K.;Piao, X.S.;Wang, D.;Li, P.F.;Xue, L.F.;Salmon, Lorraine;Zhang, H.Y.;Han, X.;Liu, L.
    • Asian-Australasian Journal of Animal Sciences
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    • v.24 no.8
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    • pp.1164-1172
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    • 2011
  • Two experiments were conducted to evaluate the efficacy of Trichoderma reesei derived phytase for pigs fed diets with fixed calcium to total phosphorus ratios (1.5:1). In Exp. 1, 280 weaned pigs (initial BW of $10.32{\pm}1.94$ kg) were allocated to one of five dietary treatments on the basis of weight and gender in a randomized complete block design. Treatments were the low phosphorus (0.6% Ca, 0.4% total P and 0.23% available P) diets supplemented with 0, 250, 1,000, or 2,000 FTU phytase/kg of diet and a positive control diet (PC; 0.85% Ca, 0.58% total P and 0.37% available P). The treatments were applied to seven pens with eight pigs per pen, half male and half female. In Exp. 2, six barrows fitted with ileal T-cannula (initial BW = $35.1{\pm}1.6$ kg) were assigned to three dietary treatments with a double $3{\times}3$ Latin square design. The dietary treatments were the low-phosphorus diet (0.53% Ca, 0.34% total P and 0.14% available P), the low phosphorus diet plus 1,000 FTU phytase/kg and a positive control diet (0.77% Ca, 0.50% total P and 0.30% available P). In Exp. 1, there were linear increases (p<0.01) in weight gain, phosphorus absorption, bone strength, calcium and phosphorus content of fat-free dried bone and plasma phosphorus concentrations with increasing dose rate of phytase. The performance of pigs fed the diets with 250, 1,000, or 2,000 FTU of phytase/kg did not differ from pigs fed the PC diet. Pigs fed diets with 1,000 or 2,000 FTU of phytase/kg did not differ from pigs fed the PC diet in bone characteristics. The apparent digestibility of dry matter, crude protein, ash and energy was not affected by dietary treatment. However, pigs fed the PC diet excreted more fecal phosphorus (g/d, p<0.01) and fecal phosphorus per BW gain (g/kg) than pigs fed the diets with phytase. Phytase linearly decreased (p<0.01) fecal phosphorus excreted per BW gain (g/kg), plasma calcium concentration as well as plasma and bone alkaline phosphatase activity. In Exp. 2, phytase supplementation in the low-P diet increased (p<0.05) the apparent ileal digestibility (AID) of Ca, P, leucine, lysine, phenylalanine, alanine and cysteine, tended to AID of crude protein, isoleucine, threonine, asparagine and serine. In conclusion, the novel phytase originated from Trichoderma reesei is effective in releasing Ca, P, and amino acids from corn soy based diet for pigs.

Comparative Study on the Nurses' Job Satisfaction between the Oriental Medicine Ward and the General Ward (한방병동과 일반병동 간호사의 직무만족도의 비교연구)

  • Byun, Chang-Ja;Choi, Sang-Soon;Paik, Seung-Nam;Lee, Mi-Aie
    • Journal of Korean Academy of Nursing Administration
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    • v.1 no.1
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    • pp.97-111
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    • 1995
  • In our society today, a variety of medical caring system, along with a scientific development in the area of oriental medical science plus national demand, has increased the augmentation and the opening of oriental wards and hospitals (Han Bang), which has come to create an additional requirement of nursing activity at oriental medicine wards should be different from that of the general wards or the same as the other. In view of this, various studies need to be made in this connection. The purpose of this study is to comprehend the number of nurses who want to work at oriental medicine wards and measure job satisfaction in nursing as compared with those working at general wards so as to provide basic materials for future assignment and supplementary training for the nurses. An attempt was made to contribute toward nursing administration on the one hand improving nursing training course on the other hand. A total of 72 nurses currently working at two oriental medicine hospitals available in Seoul and 82 general nurses were selected for this study using the questionaire from December 1993 to January 1994. An instrument for the study was based on the measurement of work satisfaction developed by Paula L. Stamps including 37 questions complemented by Kim for revision (1993) and 14 questions regarding general characteristics and oriental medicine wards. The instrument to test dependability showed Cronbach's=0.7711. The collected data have been processed by computer package SPSS. General characteristics of the two groups and the matters involved in oriental medicine wards were calculated into real figure and percentage an similarities between the two groups were analyzed by t-test and F-test according to the characteristics of variables. The comparative test on work satisfaction among the two groups including general characteristics and work factors were conducted by t-test and F-test. The major findings as a result of the study are as follows : 1. As general characteristics, age group of $26{\sim}30$ years are more than any segment of age. As to marital status, the number of those in single status is slightly higher than the married. Approximately 80% of them are graduates of nursing schools and nursing colleges. They are mostly in service for one to three years. There is no significant difference between the two groups. 2. The number of those who want to work at oriental medicine wards represents 40.3% against 58.4%, being in favor of general wards. 3. The reason for service at oriental medicine wards is that "there is room for potential research" which happened to rank first, followed by "easy job," "good working atmosphere" and "growing interest in oriental medicine." 4. Work satisfactions among nurses who work at oriental medicine wards prove greater than that of nurses who work at general wards. 5. Work satisfaction between the two groups by work factors is reflected with significant difference statistically on task requirement, interaction and doctor-nurse relationships. 6. The general charcateristics and the work satisfaction by work factors prove that there are significant difference in age, marital status, education and the period of work. They tend to be more satisfied with the work as they grow in age. Significant differneces are found in the work factors such as autonomy, adiministration and professional job in the relationship with doctor-nurse. As to marital status, the married are more satisfied than the unmarried. There are significant differneces in the factors respecting administration and doctor-nurse college graduates are highly satisfied with task requirement. However, satisfaction with the professional level has proven the highest degree for those having master degree. The period of work and satisfaction : There are significant differneces in task requirement, administration, interactions, professional level and doctor-nurse relationships. As a general rule, the degree of satisfactions is in proportion to the lengrh of service. The following conclusions are drawn based on the fndings mentioned above. Even though the work satisfaction of the nurse who work at oriental medicine ward is relatively high, it is desired that personal consultation be given as to disposition of nurses when they are assigned to oriental medicine wards. It is also recommended that lectures on oriental medicine be conducted through supplementary training and/or basic nursing course in order that they may be motivated for ingenious activities with an increasing sense of self-esteem which will eventually enhance positive changes for the patients who are in need of oriental medicine nursing and for the medical teams. In addition, joint reseaches involvingclinical care and education should be in constant process for unique and scientific development for those who are subject to oriental medicine nursing care.

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Effects of Different Levels of Crushed Bamboo Chip on Performance and Carcass Characteristics in Holstein Steers (파쇄 대나무 급여수준이 젖소 거세우의 성장과 도체특성에 미치는 영향)

  • 안병홍;강춘성;추교문;조희웅
    • Journal of Animal Science and Technology
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    • v.48 no.3
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    • pp.401-414
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    • 2006
  • Twenty eight Holstein steers 12 months old and weighing about 300kg were andomly allotted into one of four groups being fed ammoniated rice straw(ARS) and substituted 30%, 40% and 50% crushed bamboo chip for ARS to determine the effects of different levels of bamboo chip on performance, digestibility and carcass characteristics. Daily weight gain was reduced as the substitution levels of bamboo chip for ARS as a roughage source increased but there were no differences in daily weight gain between steers fed ARS alone and 30% bamboo chip for ARS. Concentrates intakes were not different between treatments by the substitution levels of bamboo chip for the whole fattening period. Roughage intake tended to increase as the substitution levels of bamboo chip increased. Total feed intake was not affected by the substitution levels of bamboo chip. However, feed efficiency got worse with increasing levels of bamboo chip. Animals fed the roughage substituting 30% bamboo chip for ARS were higher in profit by 13% than animals fed ARS alone as a roughage source. Digestibilities of Dry matter(DDM) and crude fiber(DCF) were highest in animals fed ARS alone as a roughage source. DDM's were lower in higher substitution levels of crushed bamboo chip but there were no differences in DCF among animals fed different levels of bamboo chip as a roughage source. Crude protein digestibility was not affected by ammoniated rice straw or by the different levels of bamboo chip. Dressing percentage and backfat thickness were not affected by ammoniated rice straw or by the levels of bamboo chip but ribeye area was narrowed as the levels of bamboo chip increased. Beef color, fat color, texture, maturity and marbling score were not affected by feeding of ammoniated rice straw or by the levels of bamboo chip. According to these results, it may be concluded that profit can increase when Holstein bulls are castrated and roughage containing ammoniated rice straw plus 30% bamboo chip is offered.

Antioxidative Effect of Pyruvate, Taurine and Melatonin, and Relationships of the Evaluation Methods on Boar Sperm Viability for In Vitro Storage (돼지 정자의 체외조본에 있어 Pyruvate, Taurine 및 Melatonin의 항산화효과와 평가방법의 상관관계 분석)

  • Jang, H.Y.;Park, C.K.;Cheong, H.T.;Kim, J.T.;Lee, H.K.;Im, S.K.;Yang, B.K.
    • Journal of Animal Science and Technology
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    • v.49 no.6
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    • pp.729-736
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    • 2007
  • The objective of this study was to investigate the anti-oxidative effects of pyruvate, taurine and melatonin on sperm characteristics(motility, membrane integrity) and lipid peroxidation(LPO) for in vitro storage of boar semen. Semen was treated with various antioxidants such as pyruvate(1mM), taurine(50mM) and melatonin(100nM) with or without 100uM H2O2. Antioxidant treatments were significantly increased the sperm motility when compare to control group in all incubation periods(P≤0.05). Hypoosmotic swelling test(HOST), membrane integrity was similar to the result of motility. In lipid peroxidation measurement by TBA reactions of spermatozoal plasma membrane, malondialdehyde(MDA) level in control and antioxidant treatments were lower than those of antioxidant plus H2O2 or H2O2 treatment for 3 to 6 h incubation period. Relationships of evaluation methods for sperm viability were investigated by motility, membrane integrity and lipid peroxidation. Among evaluation methods, LPO vs motility and membrane integrity vs LPO were negatively correlated(-0.23~-0.92 and -0.68~-0.85), but membrane integrity vs motility was positively correlated (0.53~0.94) in all treatments. These experiments indicate that supplementation of antioxidant to the semen extender can increase the sperm motility and membrane integrity and decrease the lipid peroxidation of spermatozoal plasma membrane. The HOST might be utilized to evaluate the sperm quality instead of lipid peroxidation or motility.

Effect of Dietary Inuloprebiotics on Performance, Serum Immunoglobulin and Caecal Microflora in Broiler Chickens (이눌로프리바이오틱스의 사료 내 첨가가 육계의 성장능력, 혈액 면역물질 및 맹장 미생물에 미치는 영향)

  • Park, Sang-Oh;Park, Byung-Sung
    • Korean Journal of Organic Agriculture
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    • v.17 no.4
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    • pp.539-555
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    • 2009
  • The potential of encapsulated inuloprebiotics from domestic Jerusalem artichokes (Helianthustuberosus) as natural antibacterial growth promotor for an antibiotic replacement in broiler chickens was presently assessed through assays of growth performance, serum immunoglobulin production and influence on caecal microflora. Two hundred-forty, 1-day-old, male broilers (Ross 308) were randomly allotted to four treatments (T1-T4), with three replicate pens per treatment and 20 chicks per pen. Broiler chicks were fed a basal diet (T1: control) or basal diet plus antibiotics (T2: Chlorotetracycline, 0.10%), 300 ppm of the inuloprebiotics (T3), or 450 ppm of the inuloprebiotics (T4) for 35 days. Body weight, dressing percentage or weight of breast and thigh muscles relative to carcass weight of T3 and T4 broiler chickens was significantly (P<0.05) higher than T1 and T2 broiler chickens. The weight of abdominal fat from T3 and T4 broiler chickens were significantly (P<0.05) lower than that of T1 and T2 chickens. Serum immunoglobulins in the T3 and T4 groups were significantly (P<0.05) elevated compared to the T1 and T2 groups. The weight of immune organs, thymus and Bursa of Fabricius relative to live body weight in the T3 and T4 groups were significantly (P<0.05) higher than the T1 and T2 groups. Bifidobacteria and Lactobacillus, which are beneficial bacteria, were present in greater numbers in the caecum of T3 and T4 birds than T1 and T2 groups, whereas potentially harmful Escherichiacoli and Salmonella were present in lower numbers, with differences being significant (P<0.05). These results suggest that a diet supplemented with 300 ppm of inuloprebiotics has potential as an antibiotic replacement for organic livestock feed supplement intended to improve production of broiler chicken.

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Licochalcone C Induces Autophagy in Gefitinib-sensitive or-resistant Human Non-small Cell Lung Cancer Cells (Gefitinib-민감성 또는 내성 비소세포폐암 세포에서 Licochalcone C에 의한 자가포식 유도)

  • Oh, Ha-Na;Yoon, Goo;Chae, Jung-Il;Shim, Jung-Hyun
    • Journal of Life Science
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    • v.29 no.12
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    • pp.1305-1313
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    • 2019
  • Licochalcone (LC), isolated from the roots of Glycyrrhiza inflata has multiple pharmacological effects including anti-inflammatory and anti-tumor activities. To date, Licochalcone C (LCC) has induced apoptosis and inhibited cell proliferation in oral and bladder cancer cells, but lung cancer has not yet been studied. In addition, no study reported LCC-induced autophagy in cancer until now. The present study was designed to investigate the effect of LCC on gefitinib-sensitive and -resistant lung cancer cells and elucidate the mechanism of its action. The 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay data showed that LCC significantly inhibited cell viability in non-small cell lung cancer (NSCLC) HCC827 (gefitinib-sensitive) and HCC827GR (gefitinib-resistant) cell lines. Interestingly, Annexin V/7-aminoactinomycin D double staining and cell cycle analysis showed an apoptosis rate within about 20% at the highest concentration of LCC. LCC induced G2/M arrest by reducing the expression of the cell cycle G2/M related proteins cyclin B1 and cdc2 in NSCLC cell lines. Treatment of LCC also induced autophagy by increasing the expression of the autophagy marker protein microtubule-associated protein 1 light chain 3 (LC3) and the protein autophagy-related gene 5 involved in the autophagy process. In addition, LCC increased the production of reactive oxygen species (ROS), and the cell viability was partially restored by treatment with the ROS inhibitor N-acetyl-L-cysteine. In western blotting analysis, the expression of cdc2 was increased and LC3 was decreased by the simultaneous treatment of NAC and LCC. These results indicate that LCC may contribute to anti-tumor effects by inducing ROS-dependent G2/M arrest and autophagy in NSCLC. In conclusion, LCC treatment may be useful as a potential therapeutic agent against NSCLC.

Effect of Panax ginseng on the Graft-versus-Host Reaction, Production of Leucocyte Migration Inhibitory Factor and Expulsion of Adult Trichinella spiralis in Mice (인삼이 이식편대숙주반응, 대식세포유주저지반응 및 Trichinella spiralis의 expulsion에 미치는 영향)

  • Ha, Tai-You;Lee, Jeong-Ho;Kim, Sang-Hyung
    • The Journal of the Korean Society for Microbiology
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    • v.21 no.1
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    • pp.133-144
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    • 1986
  • This study was undertaken to assess the effect of ginseng administration on T lymphocyte induced local xenogenic graft-versus-host(GVM) reactions which were induced with thymocyte, spleen cell and lymph node cell of ICR mice. Mice received daily 10mg of 70% alcohol ginseng extract oral1y for 100days and control mice remained untreated for the same period of time. The cells from donor mice were injected intradermally into the closely shaven abdominal skin of Sprague-Dawley rats for GVH tests. The thymocyte from control(ginseng-untreated) mice showed a negative local GVH reaction, whereas thymocyte from experimental(ginseng-treated) mice showed a positive reaction with the rate of 17.4%. When spleen cells were injected, the incidence of positive local GVH reaction was 66.7% among ginseng-treated mice, as opposed to incidence of 45.5% of positive local GVH reaction among control mice. The incidence of positive local GVH reaction of the lymph node cells when injected into a recipient was 71.4% among ginseng-treated mice as compared with that of 18.9% among control mice. The relationship between spleen cell inoculum and intensity of the local GVH reaction was assessed in ginseng-untreated mice. The intensity of GVH reaction clearly appears to be dose related. In ginseng-treated mice, a minimum of $1{\times}10^7$ spleen cell was required for production of positive local GVH reaction with almost linear relationship up to an inoculum of $5{\times}10^8$ cells. In control mice, however, a minimum of $1{\times}10^8$ spleen cells was required for positive GVH reaction. These results strongly suggest that the ginseng administration augments significantly the local xenogenic GVH reaction which was used to assess T lymphocyte function and immunocompetence of mice and in addition to this, these results appear to support previous suggestions that the local GVH reaction consitutes a qualitative test of the functional activity of T lymphocytes. These results may be the first to induce local GVH reaction, employing rats as recipient and mice as donor. This study was also desingned to investigate some of the effects of ginseng extract on lymphocyte-macrophage interactions. This was accomplished by in vitro quantification of 1) migratory inhibitory factor(MIF) synthetic capacity of splenic lymphocytes in mice previously primed with ginseng 2) MIF responsiveness of mouse peritoneal macrophages or chicken peripheral leucocytes under the presence of ginseng extract 3) migration ability of chicken peripheral leucocytes by direct stimulation of ginseng extract or ginseng saponin and 4) immunosuppressive effects of immunosuppressants such as cyclophosphamide, cyclosporin A or dexamethasone. Mice divided equally into the ginseng and the saline groups, which received intraperitoneally daily 0.2ml of ginseng absolute alcohol-extract(5mg/ml) and same amount of saline for 15 days, respectively. The cellular immune responsiveness of these mice was assayed 15 days after ginseng pretreatment. Splenic lymphocytes of mice treated with ginseng, when stimulated with sensitized specific-antigen such as sheep red blood cells or toxoplasmin, or with polyclonal activator concanavalin A, produced significantly more MIF than those of control saline group. MIF responsiveness of normal mouse macrophages was significantly augmented when assayed under the presence of ginseng extract (1mg/ml). The migratory ability of normal chicken leucocytes in the absence of MIF was significantly decreased by the stimulation of ginseng extract alone. MIF response was significantly decreased by immunosuppressants and this impaired response was not restored by ginseng pretreatment. This study was additionally performed to evaluate the effect of ginseng on the expulsion of adult Trichinella spiralis in mice. ICR mice were infected experimentally by esophageal incubation of 300 T. spiralis infective muscle larvae prepared by acid-pepsin digestion of infected mice. and received oral administration of 70% alcohol ginseng extract(10mg/mouse/day) for the indicated days plus 4 days before infection. At various times after infection, the number of adult T. spiralis worms in small intestines was determined. Interestingly, ginseng-treatment was accompanied by accelerated expulson of T. spiralis. These results led to the conclusion that Panax ginseng caused some enhancing effect on GVH reaction, macrophage migration inhibition reaction and expulsion of T. spiralis. In addition these results suggested that the mechanisms responsible for this enhancement of ginseng may be chiefly or partially due to nonspecific stimulation of cell-mediated immune response.

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Studies on Yield Increase of Soybean as a Protein Source -Varietal response of yield components, protein and oil yield to different sowing dates and calcium levels in soybean- (단백자원으로서의 대두증산에 관한 연구 - 품종 파종기 및 석회시용량의 차이가 대두의 수량형질과 단백질 및 유분생육량에 미치는 영향 -)

  • S. K. Hyun;Eun-Woong Lee;Chung-Yong Lee;Yong-Woong Kwon
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.8 no.1
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    • pp.1-4
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    • 1970
  • To study the varital response of grain, protein and oil yield to different sowing dates and calcium levels in soybean, the most important crop as a protein source in Korea, this experiment was conducted in 1969. Three leading soybean varieties (Choongbukbaek, Ryooku#3 and Changdanbaekmok) were sown at May 22,, June 11 and July 1 under 3 different calcium levels, 0.50 and 100kg per 10a respectively. The results are summarized as follows: 1. Ryonku #3 showed the highest grain yield because of the highest number of pods per hill. In order of protein content, and oil content of grain, Choongbukbaek>Ryooku#3>Changdanbaekmok and Changdanbaekmok>Choogbukbaek>Ryooku#3 were found. Ryooku#3 also showed the highest protein and oil production per unit area owing to the highest grain yield. However. varietal differences of the grain yield the protein and the oil production per unit area varied along the different sowing dates. Interactions between varieties and sowing date on the grain yield should be considered in practice. 2. No difference in the grain yield was found between the first sowing date (May22) and the second (June11) on average. The grain yield in the plot of the third sowing date (July l)was strikingly decreased mainly by the smaller number of pods per hill. The protein and the oil content were not varied significantly by the different sowing dates. The protein and oil production per unit area were lowest in the plot of the third sowing date owing to the decreased grain yield. 3. More calcium application increased the number of branches per hill, the number of pods per hill, and the grain yield. The highest grain yield was found in the plot received 100 kg of calcium hydroxide per 10are. Protein content increased in higher calcium level, but oil content was highest in the plot of noncalcium. More protein production per unit area was gotten by more calcium application because of higher grain yield and protein content. all production increased in higher calcium level by the increased grain yield. 4. High plus (+) correlation was found between stem length and stem weight per hill stem length and grain weight, stem length and grain yield, stem weight per hill and number of pods per hill and grain weight, number of branches per hill and grain weight, number of pods per hill and grain yield, and grain weight and protein content of grain. Minus(-) correlation was recognized between number of pods per hill and grain weight.

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Effects of Dietary Supplementation of α-Tocopherol and Selenium on Performance and Physicochemical Properties of Chicken Thigh Meat (α-Tocopherol과 Selenium의 첨가 급여가 육계의 생산성 및 닭 다리육의 이화학적 특성에 미치는 영향)

  • Kim, Young-Jik
    • Korean Journal of Poultry Science
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    • v.38 no.2
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    • pp.129-136
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    • 2011
  • The objective of this study was to evaluate the effects of different levels of ${\alpha}$-tocopherol and selenium in broiler diets on performance and physicochemical properties of chicken thigh meat. A total of 360 broiler chicks divided into six groups were fed a basal diet (control) or basal diet supplemented with 50 IU ${\alpha}$-tocopherol/kg (T1), 100 IU ${\alpha}$-tocopherol/kg (T2), 200IU ${\alpha}$-tocopherol/kg (T3), 0.3 ppm selenium/kg (T4), and 100 IU ${\alpha}$-tocopherol/kg + 0.3 ppm selenium/kg (T5) for five weeks. Growth performance and proximate composition of chicken thigh meat were not influenced by all dietary treatments, except for crude fat, which was significantly lower in the treatment with ${\alpha}$-tocopherol or selenium, or both compared to control. The dietary ${\alpha}$-tocopherol and selenium supplementation had no significant effects on pH, CIE $L^*$ (lightness), and $b^*$ (yellowness) values but TBARS (thiobarbituric acid reactive substance) values were decreased (P<0.05) by the addition of ${\alpha}$-tocopherol and selenium. CIE $a^*$ (redness) values increased significantly with added ${\alpha}$-tocopherol and selenium relative to the control (P<0.05). Likewise, changes in fatty acid composition in chicken thigh meat with the dietary supplementations with ${\alpha}$-tocopherol, selenium and their combination significantly increased (P<0.05) unsaturated fatty acid, whereas saturated fatty acid were decreased. It was concluded that the addition of 200 IU ${\alpha}$-tocopherol (T3) and 100 IU of ${\alpha}$-tocopherol plus 0.3 ppm selenium (T5) were most effectiveness in the improvements in the lipid oxidative stability of chicken meat when compared to the control.

Bond Orbital Theory of Chemical Reactivity (反應性의 結合 Orbital 理論)

  • Yang, Kang;Ree, Tai-Kyue
    • Journal of the Korean Chemical Society
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    • v.8 no.1
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    • pp.20-24
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    • 1964
  • The linear combination of bond orbitals method is used to investigate the reactivity of halomethanes in abstraction reactions by atoms. The activation energy is evaluated on the assumption that, in an activated complex, two electrons in a bond to be broken become completely isolated from the rest of the ${\sigma}$-electron systems. Such a model leads to an intuitively attractive concept that the interactions between the reactive bond and the neighboring bonds govern the reactivity of ${\sigma}$-electron systems. The resulting equation for the activation energy, ${\varepsilon},\;is:\;{\narepsilon}= ${\varepsilon}={\zeta}+$$${\sum}_{i=1}^3$${\eta}c-I,$ c-4 Here, subscript C-4 indicates the bond to be broken, while C-i represents the other three bonds surrounding the reactive bond; ξ is the activation energy of a hypothetical reaction of an isolated C-4 bond and an attacking atom; and ${\eta}$C-i,C-4 stems from the stabilizing interacting of C-4 bond with neighboring C-i bonds. A choie of η′s consistent with bond strength data simplifies the above equation to a form ${\varepsilon}={\zeta}\;+\;N{\eta}c$-H, C-4 where N denotes the number of C-H plus C-F bond in halomethanes. In agreement with this equation, experimental -values increase linearly with increasing N.

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