• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.434-442
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• 2008

The objective of this study was to determine the optimum ratio of methionine to methionine plus cystine for growing pigs. A nitrogen balance trial was conducted using a total of 21 barrows (Large WhiteLandrace) over two replicates. The initial body weight was $20.36{\pm}1.22kg$ (mean${\pm}$SD) in the first replicate and $23.54{\pm}1.02kg$ (mean${\pm}$SD) in the second. For each replicate, the 21 pigs were randomly assigned to one of seven dietary treatments with three observations per treatment. The diets included a methionine and cystine-deficient basal diet with all other essential nutrients meeting nutrient requirements and six diets formulated with graded levels of DL-methionine (0.00, 0.03, 0.06, 0.10, 0.13, 0.16%) and $L-Cystine{\cdot}HCl{\cdot}H_2O$ (0.19, 0.15, 0.11, 0.07, 0.04, 0.00%). This resulted in ratios of methionine to methionine plus cystine of 41.3, 29.6, 35.3, 41.2, 46.0, 51.6 and 57.5%. Each experimental period lasted 12 days consisting of a seven-day adaptation period followed by a five-day total collection of urine and feces. During the collection period, pigs were fed 900 g/day for the first replicate and 1,200 g/day for the second replicate. The feed was provided in three equal portions at 0800, 1500, and 2200 h daily. Pigs had ad libitum access to water after feeding. There was a linear (p<0.01) and quadratic (p<0.01) effect on daily gain and feed conversion as the ratio of methionine to methionine plus cystine increased. Pigs receiving the diets providing a methionine to methionine plus cystine ratio of 51.6% had the best daily gain and feed conversion. Plasma urea nitrogen was also lowest for this treatment. Nitrogen retention increased (p<0.01) as the relative proportion of methionine increased up to 51.6% and then a downward trend occurred at 57.5%. The quadratic regression model, as well as one- and two- slope regression line models, were used to determine the optimum ratio of methionine to methionine plus cystine. Eliminating the 35.3% methionine to methionine plus cystine treatment resulted in $R^2$ values in excess of 0.92. The optimal ratio of methionine to methionine plus cystine was estimated to be 54.15% for nitrogen retention and 56.72% for plasma urea nitrogen.

• Applied Biological Chemistry
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• v.16 no.3
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• pp.118-127
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• 1973

Effects of nitrogen sources oi phosphorus sensitivity in soybeans were investigated using three nitrogen source ($NH_4-N,\;NO_3-N$ and urea) and six cultivars (Lee, Hill, R56-49, Harosoy, Clark-63 and Chippewa), differing in phosphorus sensitivity. Growth inhibition with ammonium or urea medium increased with phosphorus sensitivity indicating that the phosphorus sensitive cultivars are also sentitive to ammonium. The sensitive Clark-63 was inhibited two folds more than the tolerant Lee in ammonium medium. These results strongly suggest that phosphorus sensitivity is closely linked to nitrogen metabolism and ammonium toxicity. Nitrogen sources gave special morphorogical growth patterns (short internode-many branchs in $NO_3-N$, long internode-no branches in $NH_4-N$ and a low top to root ratio in urea) by affecting differently the growth of plant organs.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.8
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• pp.1093-1097
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• 2004

This study was aimed to establish the amount of enzose (corn dextrose) for optimum N fixation in urea treated corncobs (UTC) and their dietary effect on nutrient intake, digestibility and milk yield in crossbred cows. Corncobs were treated with 5% urea and ensiled in laboratory silos with 0, 2, 4 and 6% enzose for 15 days. Total nitrogen (N), neutral detergent fiber (NDF) and neutral detergent insoluble N contents were increased in UTC with the level of enzose. Five early lactating crossbred cows (Sahiwal$\times$Holstein Frisian) were used in a 5$\times$5 Latin Square Design to see the influence of UTC ensiled with 6% enzose on nutrient intake, digestibility, milk yield and its composition. Five iso-nitrogenous and iso-caloric diets were formulated. The UTC30 (control), UTC40, UTC50, UTC60 and UTC70 diets contained 30% UTC ensiled without enzose and 40, 50, 60, 70% UTC ensiled with 6% enzose, respectively. Dry matter, NDF and ADF intakes were increased with the increasing level of UTC ensiled with enzose in the diets of cows. Dry matter, NDF and ADF digestibilities were significantly higher with diets containing UTC ensiled with enzose. Milk yield was significantly higher in cows fed UTC70 compared to those fed on other diets. The milk crude protein percentage was significantly different across treatments. However, milk fat, total solids, solid not fat, true protein and non-protein nitrogen contents of milk remained similar across all diets. Ensilation of UTC with 6% enzose improved the nitrogen retention and thus enhanced the feeding value of UTC for lactating cows.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.620-626
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• 2017

Objective : Although venous thromboembolism (VTE) is frequently related to dehydration, the impact of dehydration on VTE in acute ischemic stroke (AIS) is not clear. This study investigated whether dehydration, as measured by blood urea nitrogen (BUN)/creatinine (Cr) ratio, influences the occurrence of VTE in patients with AIS. Methods : This is a retrospective study of patients with AIS between January 2012 and December 2013. Patients with newly diagnosed AIS who experienced prolonged hospitalization for at least 4 weeks were included in this study. Results : Of 182 patients included in this study, 17 (9.3%) suffered VTE during the follow-up period; in two cases, VTE was accompanied by deep vein thrombosis and pulmonary embolism. Patients with VTE were more frequently female and had higher National Institutes of Health Stroke Scale (NIHSS) score, more lower limb weakness, and elevated blood urea nitrogen BUN/Cr ratio on admission. In a multivariate analysis, BUN/Cr ratio >15 (odds ratio [OR] 8.75) and severe lower limb weakness (OR 4.38) were independent risk factors for VTE. Conclusion : Dehydration on admission in cases of AIS might be a significant independent risk factor for VTE.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.10
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• pp.1627-1634
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• 2018

Objective: The study aimed to evaluate the effect of replacing wheat bran for cactus cladodes plus urea (0%, 25%, 50%, 75%, and 100%) on the intake of nutrients, nitrogen balance, microbial protein synthesis, and rumen fermentation for steers. Methods: Five crossbred steers (1/2 Holstein-Zebu), with rumen cannula and an average body weight of $180{\pm}5.3kg$, were assigned to a $5{\times}5$ Latin square design. Dietary treatments consisted of the replacement of the total of wheat bran in basal diet by cactus cladodes using the following proportions: 0% for basal diet, 25%, 50%, 75%, and 100% cactus cladodes replacing wheat bran. Urea was added to the diets to adjust the crude protein (CP) content to 130 g/kg dry matter. Results: Maximum dry matter intake (5.73 kg/d) and maximum nitrogen balance (103 g/d) were estimated for 54.6% and 70.8% replacement levels of wheat bran. The maximum microbial protein production (44.6 g/d) was obtained at a replacement level of 49.7%, and a medium value (125 g CP mic/kg total digestible nutrients) of microbial protein efficiency was observed. The rumen pH increased linearly according to cactus cladodes inclusion, while the ammonia nitrogen medium value was 24.5 mg/dL. Conclusion: The replacement of 55% wheat bran for cactus cladodes plus urea in the diet of crossbred steers is recommended.

• Biomedical Science Letters
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• v.8 no.4
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• pp.235-244
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• 2002

This study was carried out to determine the blood and milk progesterone by enzyme-linked immunosorbent assay (ELISA), and milk urea nitrogen (MUN) in cows. MUN and protein concentration were determined using automated infared procedures. The optimum conditions of ELISA system was investigated including the first and second antibody titres, bound percent, and enzyme conjugate and also the factors on MUN and protein concentration by sampling procedures and addition of preservatives. Progesterone antibodies did not react to pregnenlone, testosterone, estrone, estradiol-l7$\beta$, aldosterone, cortisol, corticosterone and 11$\alpha$-dehydroxycortisone (DOC), but reacted with only progesterone. The intra and inter-assay coefficient of variation 4.5%, 6.1~9.4% when used of bovine serum. The morning, MUN concentration (17.6$\pm$2.8 mg/100 ml) in the 13 herds was similar to that of evening MUN concentration of the lactating cows from the same herd. A significant relationship between morning and evening milk samples of upper parameters was found r=0.93. Difference in MUN concentration with sampling procedures and using of preservatives were investigated.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.119-124
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• 2007

Milk components analysis was carried out milk yield(MY), milk fat(MF), milk protein(MP), milk urea nitrogen(MUN), milk solid(MS), day of non-pregnant condition(DNPC), and days of primipara(DPRI) involved. Dairy farms were divided high, middle and low groups according to the standard records for milk components. Examination records were divided by farm, parity, year, season and month, the number of samples were 28,957. MUN concentration was below 12 mg and when the MPP was below 3.0%, the days of non-pregnant condition were $94{\pm}10.77$ days but concentration of MUN was under 12 mg and when MPP was above 3.2%, longer period of non-pregnant condtion of $181.3{\pm}9.25$ was noted. The days of gestation of the first calving cow was $495.9{\pm}9.04$ days when the concentration of MUN was below 12mg/dl and MPP was under 3.0%. If the concentration of MUN was 12 mg/dl and when the MPP was over 3.2%, the days of gestation were $511.0{\pm}8.36$ days. It was believed that the concentrations of MPP and MUN have significant effects on the days of non-pregnant condition and the days of gestation. Determination of MY, MF, MS, and MUN was Milkoscan $4,000{\sim}5,000$ Serier(FOSS Electric Co., Copenhagen, Denmark). MUN standard concentration was 12-18(mg/dl) similar to blood urea nitrogen(BUN). Mutual relationship of milk components(MF, SCC, MY, DNPC, MS) and MUN concentration was low in regression analysis.

• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.455-461
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• 2000

Abstract Spirulina platensis was grown in SWlUe waste to reduce inorganic compowlds and simultaneously produce feed resources. Spirulina platensis prefers nitrogenous compounds in Ibe order: $NH_4^{+}-N>NO_3^{-}-N>simple-N$ such as urea and simple amino acids. It even consumes $NH_4^{+}-N$ first when urea or nitrate are present. Therefore, the content of residual $NH_4^{+}-N$ in Spimlina platensis cultures can be determined by the relative extent of the following processes: (i) algal uptake and assimilation; (ii) ammonia stripping; and (iii) decomposition of urea to NH;-N by urease-positive bacteria. The removal rates of total nitrogen ffild total phosphorus were estimated as an indicator of the treatment effIciency. It was found that Spirulina platensis was able to reduce 70-93% of $P_4^{3-}-P$, 67-93% of inorganic nitrogen, 80-90% of COD, and 37-56% of organic nitrogen in various concentrations of swine waste over 12 days of batch cultivation. The removal of inorganic compounds from swine waste was mainly used for cell growth, however, the organic nitrogen removal was not related to cell growlb. A maximum cell density of 1.52 dry-g/l was maintained with a dilution rate of 0.2l/day in continuous cultivation by adding 30% swine waste. The nitrogen and phosphorus removal rates were correlated to the dilution rates. Based on the amino acid profile, the quality of the proteins in the Spirulina platensis grown in the waste was the same as that in a clean culture.ulture.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1290-1302
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• 2016

Microalgae are being researched for their potential as attractive biofuel feedstock, particularly for their lipid production. For maximizing biofuel production, it is necessary to explore the effects of environmental factors on algal lipid-producing potential. In this study, the effects of nitrogen (N) sources (NO₂-N, NO₃-N, urea-N, NH₄-N, and N-deficiency) and carbon-to-nitrogen ratios (C/N= 0, 1.0, 3.0, and 5.0) on algal lipid-producing potential of Chlorella sp. HQ were investigated. The results showed that for Chlorella growth and lipid accumulation potential, NO₂-N was the best amongst the nitrogen sources, and NO₃-N and urea-N also contributed to algal growth and lipid accumulation potential, but NH₄-N and N-deficiency instead caused inhibitory effects. Moreover, the results indicated that algal lipid-producing potential was related to C/N ratios. With NO₂-N treatment and carbon addition (C/N = 1.0, 3.0, and 5.0), total lipid yield was enhanced by 12.96-20.37%, but triacylglycerol (TAG) yields decreased by 25.52-94.31%. As for NO₃-N treatment, carbon addition led to a 17.82-57.43%/25.86-82.67% reduction of total lipid/TAG yields. When NH₄-N was used as the nitrogen source, total lipid/TAG yields were increased by 46.67-113.33%/28.99-74.76% with carbon addition. The total lipid/TAG yields of urea-N treatment varied with C/N ratios. Overall, the highest TAG yield (TAG yield: 38.75 ± 5.21 mg/l; TAG content: 44.16 ± 4.35%) was achieved under NO₂-N treatment without carbon addition (C/N = 0), the condition that had merit for biofuel production.

• Journal of Ginseng Research
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• v.36 no.3
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• pp.270-276
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• 2012

The effect of orally administered sun ginseng (SG), which is a ginseng processed by steaming, was examined in adenine-induced chronic renal failure rat. SG significantly decreased both blood urea nitrogen and serum creatinine levels, indicating an improvement of renal function. Also, SG significantly increased the urinary excretion of both urea and creatinine. Furthermore it lowered the blood pressure, and inhibited adenine-induced kidney hypertrophy and edema. Based on these findings, SG may ameliorate chronic renal failures.