• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.44-50
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• 1981

This experiments was carried out to evaluate the effect of nitrogen retention on different levels of crude protein intake according to live weight, and the crude protein and urea content in serum of the Korean native goat. The results obtained are as follows: 1. When the female goat at 8 months age (14kg) had taken nitrogen free diet, the content of endogenous urinary nitrogen was 1.29g and endogenous fecal nitrogen was 1.27g per day. Therefore, the goat needs minimum level of crude protein per day. 2. When the thermometer checked below-$10^{\circ}C$, the nitrogen retention rate showed minus reaction in spite of 20% crude protein level. This suggested that the low temperature was consumed higher energy to maintain the body. 3. The nitrogen retention rate of the pregnant female goat of 20kg live weight, however, decreased as compared with the growing goat and was 17~20%. 4. According to the levels of crude protein were lower, crude protein and urinary nitrogen contents in serum were greatly decreased.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1282-1289
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• 2001

One feeding trial and two metabolic trials were conducted to investigate the effects of lysine to protein ratio in practical swine diets on growth performance and efficiency of nitrogen retention and utilization in different growing phases. In Trial one (the feeding trial), 90 mixed sex pigs weighing $9.1{\pm}1.4kg$ (Duroc ${\times}$ Landrance ${\times}$ Beijing Black) were used to study the effects of concentrations of 5.2, 5.3, 5.8, 6.4 and 7.2 g lysine/100 g CP in diets containing 1.2% lysine on growth performance and serum urea nitrogen. The results showed that feed conversion efficiency and economic efficiency were best for pigs fed the diet containing the lysine concentration of 5.8 g /100 g crude protein. Serum urea nitrogen concentration decreased linearly (p=0.0009) and serum free lysine content increased linearly (p=0.0017) as the lysine to protein ratio in diets increased from 5.2 to 7.2 g/100 g. In Trials two and three (the metabolic trials), five growing barrows (Duroc ${\times}$ Landrance ${\times}$ Beijing black), with initial body weights of approximately $26{\pm}2.4kg$ and $56.3{\pm}3.5kg$, respectively, were allotted to five dietary treatments according to a $5{\times}5$ Latin square design. Trial two contained 5.2, 5.7, 6.1, 6.7 and 6.8 g lysine/100 g CP treatments. Trial three contained 4.6, 5.0, 5.6, 6.1 and 6.6 g lysine/100 g CP treatments. The results showed that nitrogen retention in growing pigs decreased linearly (p=0.0011 in Trial two; p=0.0099 in Trial three) as the lysine to protein ratio in diets increased. The ratio of lysine to protein in diets resulting in maximum nitrogen retention was 5.2 g/100 g and 5.0 g/100 g in Trial two and Trial three, respectively. In Trial two, apparent biological value and gross nitrogen efficiency increased linearly (p=0.0135 and p=0.0192, respectively) as the lysine to protein ratio increased from 5.2 to 6.8 g lysine/100 g CP. In summary, we concluded that the optimal Lysine to Protein Ratios for 8-20 kg and 20-80 kg pigs were 5.8 g/100 g and 5.0 to 5.2 g/100 g, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.5-14
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• 2010

A pilot-scale biological aerated filter (BAF) was operated with an anaerobic, anoxic and oxic zone at $23{\pm}1^{\circ}C$. The influent sCOD and total nitrogen concentrations in the feedwater were approximately 250 mg/L and 35 mg N/L, respectively. sCOD removal at optimum hydraulic retention time (HRT) of 3 hours with recirculation rates of 100, 200 and 300% in the column was more than 96%. Total nitrogen removal was consistently above 80% for 4 and 6 hours HRT at 300% recirculation. For 3 hours HRT and 300% recirculation, total nitrogen removal was approximately 79%. Based on fitting results, the kinetic parameter values on nitrification and denitrification show that as recirculation rates increased, the rate of ammonia and nitrate transformation increased. The ammonium loading rates for maximum ammonium removed were 0.15 and 0.19 kg $NH_3$-N/$m^3$-day for 100% and 200% recirculation, respectively. The experimental results demonstrated that the BAF can be operated at an HRT of 3 hours with 200 - 300% recirculation rates with more than 96 % removal of sCOD and ammonium, and at least 75% removal of total nitrogen.

• The Korean Journal of Ecology
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• v.19 no.2
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• pp.179-189
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• 1996

Growth and nitrogen retention of Persicaria thunbergii were investigated in the wetland microcosms which contained the plants growing on soil bed. Nitrogen solution was supplied to the microcosms with the same amount of $NH_4^{+}-N\; and\; NO_3^{-}-N$ at the rates of 0.00, 0.78, 1.57, 3.14g $N{\cdot}m^{-2}{\cdor}wk^{-1}$ from May 1 to August 31, 1995. The solution was detained for 5 days to react with soil and plant and then allowed to leach. The contents of NH_4^{+}-N\;and\; NO_3^{-}-N$ in the leachate, total Kjeldahl nitrogen, plant biomass, and soil characteristics were determined. Nitrogen retained by plant was estimated as the increment of TKN in plant biomass. The addition of 0.78 and 1.57g $N{\cdot}m^{-2}{\cdot}wk^{-1}$ resulted in significant increase of plant biomass. However, plant growth was inhibited when nitrogen was added at the rate of 3.14g $N{\cdot}m^{-2}{\cdot}wk^{-1}$. Overall, the plant biomass was positively correlated with the amount of nitrogen retained by plant and soil system. The amounts of $NO_3^{-}-N$ leached from the microcosms were 5~10 times higher than those of $NH_4^{+}-N$. While total nitrogen added ranged from 143.2 to 576.5g $N/m^2$, total leaching loss of inorganic nitrogen and nitrogen retained by plant was as little as 1.04~22.71g $N/m^2$, and 5.46~12.91g $N/m^2$, respectively. Then, the plant seemed to contribute to KDICical and microbial immobilization of nitrogen in the soil. Finally, it is suggested that a large portion of nitrogen added was lost into the air by denitrification and volatilizaton, and / or leached in organic forms.

• Journal of Animal Science and Technology
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• v.58 no.5
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• pp.21.1-21.8
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• 2016

Background: The aim of the present study was to determine the effects of feeding trace mineralsfortified mixed microbial culture (TMC) on ruminal fermentation, nutrient digestibility, blood electrolyte status, nitrogen balance, and trace mineral balance in sheep. Methods: Mixed microbes [0.6 % (v/w) of Enterobacter sp., Bacillus sp., Lactobacillus sp., and Saccharomyces sp.] were cultured with 99 % feedstuffs and 0.4 % trace minerals including zinc and copper for ensiling. Six sheep (a mean body weight of $46.5{\pm}1.2kg$) were fed two diets: a control diet (concentrate mix and rye straw) and an experimental diet (a control diet + 3.1 % TMC). Results: TMC feeding did not induce negative effects on ruminal fermentation, nutrient digestibility, blood electrolytes, and nitrogen balance in sheep. Feeding with TMC increased the intake of trace minerals (p < 0.05) and did not affect absorption of trace minerals in the whole digestive tract. Feeding with TMC increased fecal excretion and absorbable intake, and retention of zinc and copper (p < 0.05) by 71 % and 77 %, respectively. Conclusion: Feeding with TMC resulted in higher zinc and copper bioavailability and retention without any adverse effects on sheep performance.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.9
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• pp.1288-1293
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• 2002

Four adult rams ($22.25{\pm}0.90kg$) were used in a $4{\times}4$ latin square design to evaluate the rations without ($T_1$) or with supplementation of sunflower acid oil at 5 ($T_2$), 10 ($T_3$) or calcium soap at 10% of dietary DM ($T_4$) on nutrient digestibility and balances of nitrogen, calcium and phosphorus. The basal ration contained 60 parts Brazilian napier grass hay and 40 parts concentrate mixture. The DM, CF, NDF and ADF digestibilities and nitrogen retention (g/d) decreased (p<0.01) by inclusion of sunflower acid oil at 5% of dietary DM. In addition, depression (p<0.01) in digestibilities of CP, nitrogen free extract (NFE), cellulose, hemicellulose, retention of calcium and phosphorus (g/d) were also observed with increasing the level of sunflower acid oil to 10% of dietary DM. The EE digestibility, total digestible nutrients (TDN) content and calcium retention (g/d) were significantly higher (p<0.01) for ration supplemented with calcium soap. It is concluded that sunflower acid oil supplementation in free form as low as 5% of dietary DM is deleterious to fibre digestion in sheep while as calcium soap, it can be fed up to 10% of dietary DM as an energy source without any adverse effect.

• Journal of Environmental Science International
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• v.28 no.8
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• pp.669-676
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• 2019

The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.414-420
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• 2015

Nitrogen is one of main causes to induce eutrophication of water system and one of contaminants that must be treated for protection of water system. In this study, it was intended to identify a method to increase operation efficiency of municipal wastewater treatment plant (MWTP) by treating high concentration nitrogen. A laboratory scale reactor was operated by using sludge thickener supernatant in the MWTP. During operation of the laboratory scale reactor, it was intended to induce stable nitritation and analyze effects of related operation factors. As results, it was shown that the nitiritation could be induced artificially through control of retention time and sections where the stable nitiritation was induced were identified also. In particular, highly efficient nitrite conversion efficiency near 90% was identified in condition of 1 day retention time. Especially, it was shown that ammonium nitrogen load affected ammonium nitrogen removal efficiency and nitrite conversion efficiency. In the condition of high ammonium nitrogen load, the nitrite conversion efficiency and the ammonium nitrogen removal efficiency decreased. On the contrary in the condition of low ammonium nitrogen load, it was found that the nitrite conversion efficiency decreased. It means that control of ammonium nitrogen concentration and its retention time is needed for the nitritation. It is considered that for the sewage containing high load nitrogen in sludge treatment process as like the sludge thickener supernatant, the nitritation can be applied, which can be suggested as a modification method of MWTP.

• Journal of Nutrition and Health
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• v.16 no.4
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• pp.273-280
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• 1983

The effect of alteration of light-darkness cycle on the protein metabolism was studied in the rat. The light-darkness cycle was altered either every 3 or 9 days, and animals consumed diets containing 8 or 25% casein. The results were summarized as follows : 1) Food consumptions and body weight gains of the 25% casein groups were higher than those of the 8% casein groups, and, among the animals consumed 25% casein diet, the light-darkness cycle altered group had lower food consumption and body weight gain than the unaltered group. 2) Weights of liver and adrenal gland per l00g body weight were not different with the dietary protein levels, but, at the end of experimental period, the 8% casein diet group of which light-darkness cycle altered every 9 days had the smallest liver weight and the largest adrenal gland weight. 3) Liver nitrogen and plasma protein concentrations of the 25% casein groups were slightly higher than those of the 8% casein groups. 4) Percentages of nitrogen retention of the 25% casein groups at period III were slightly lower in the light-darknerr cycle altered animals than that of the unaltered group.

• Journal of Nutrition and Health
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• v.24 no.1
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• pp.20-29
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• 1991

This study was carried out to compare the protein quality of lamb and beef meat. by feeding to growing rats. Sixty weanling rats, 30 males and 30 females, were blocked into 12 groups(6 gruops of males and 6 groups of females). They were fed casein. beef, or lamb as a protein source at two levels, 6 and 15%, for 5 weeks. The amount of food intake. food efficiency ratio, protein efficiency ratio. body weight gain. and the weights of skeletal muscles and liver were measured. Nitrogen retention, protein content in the liver and skeletal muscles, and the levels of protein and cholesterol in the serum were also assayed. Summarzing the results, there were no significant differences between lamb and beef on the growth and nitrogen utilization in the rats fed same percentage of protein diet. However. rats fed 15% protein diet showed significantly higher growth rate than those fed 6%. Therefore, it can be concluded that lamb is as good a protein food as beef in terms of protein quality.