• 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.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.975-985
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• 2021

The sufficient amount of protein supply is crucial for improving the growth performance of growing beef cattle. In addition, due to the improvement in the genetic potential of the carcass weight of Hanwoo steers, dietary protein requirements may be increased during the rapid growth period. Accordingly, the dietary crude protein (CP) level in growing Hanwoo steers has been increasing in the field. However, little scientific evidence is available in relation to this. Therefore, this study was conducted to test whether a higher dietary CP level than convention would improve the growth performance and body metabolism in growing Hanwoo steers. Fifty growing Hanwoo steers were randomly divided into two groups and fed either a commercial diet (CON) or a higher CP (HCP) concentrate mix, provided with a similar level of dietary energy. Tall fescue hay was provided ad libitum. The dietary CP level did not affect growth performance and blood metabolite. Nitrogen intake, predicted nitrogen excretion, and retained nitrogen were higher in the HCP group than in the CON group (p < 0.01). Although there was no difference in the nitrogen utilization efficiency, the growth efficiency per retained nitrogen decreased in the HCP group (p = 0.02). A higher dietary CP level may increase nitrogen retention in growing Hanwoo steers without improving growth performance, which leads to reduced growth efficiency per retained nitrogen. Furthermore, considering the high price of feed protein and increased nitrogen excretion to the environment, a further increase in the protein level may not be sustainable.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.3
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• pp.151-157
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• 2000

This study aims to investigate the effect of carbon content on the surface nitrogen permeation of 13%Cr-1.8%Al alloyed stainless steels. The surface nitrogen permeation was performed at $1050^{\circ}C{\sim}1200^{\circ}C$ in the $1kg/cm^2$ nitrogen gas atmosphere. The nitrogen permeated surface layer of the specimen containing 0.03%C consists of AlN, martensite and retained austenite phases. while the surface layer of the specimen containing 0.14%C appears the $AlFe_3C_x$ phase including former three phases. The specimen containing 0.14%C shows lower total case depth than that containing 0.03%C at the nitrogen permeation temperatures of $1050^{\circ}C$ and $1100^{\circ}C$, while the total case depth of the specimen containing 0.14%C is remarkably increased at the temperature of $1150^{\circ}C$ and $1200^{\circ}C$ due to the increase in the retained austenite content. Martensitic phase, AlN and $AlFe_3C_x$ precipitate of the nitrogen permeated surface layer cause to increase the surface hardness of 550~600Hv.

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.558-563
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• 2001

A new alkalophilic strain of Bacillus pumilus JB¬05 producing bleach-stable and halo-tolerant alkaline protease was isolated from cement industry effluents in Karnataka, India. The effects of carbon and nitrogen sources on protease production by this alkalophilic strain were observed after a 30-h incubation. A high level of alkaline protease activity was obtained in the presence of starch as the carbon and peptone as the nitrogen sources. The partially purified enzyme showed an optimum temperature and pH activity at $58^{\circ}C$ and 10.5, respectively. The enzyme was completely inhibited by PMSF (95.0%) indicating it as a serine protease. It is bleach-stable as it retained 35% original activity in the presence of 10% (v/v) hydrogen peroxide at $30^{\circ}$C after 2 h and is halo-tolerant as it retained 70% original activity in the presence of 2.5 M sodium chloride at $30^{\circ}C$ after 2 h incubation.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.24-29
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• 2014

The objective of this study was to assess the effect of substituting corn with soybean hulls on the ingestive behavior and nitrogen balance of Santa Ines lambs. A total of 25 lambs with an initial body weight of $20{\pm}2$ kg at approximately six months of age, sheltered individually in stalls ($1.10m{\times}1.0m$), considering an entirely casual experimental delineation. Soybean hulls were substituted for corn at 0, 250, 500, 750, and 1,000 g/kg of dry matter (DM). The time spent feeding, ruminating, masticating, and resting was not affected by the substitution of corn with soybean hulls. In fact, the feeding efficiency in g DM/h and the rumination efficiency in g DM/bolus increased linearly with soybean hull substitution in the feed. Although the nitrogen balance was not altered by the use of soybean hulls as a substitute for corn in the diets of Santa Ines lambs, the N ingested and N digested expressed in g/d, N retained as a percentage of that ingested, and N retained as a percentage of that digested displayed quadratic behavior. In conclusion, corn can be substituted with soybean hulls up to 1,000 g/kg of dry matter in the concentrate, without changing the ingestive behavior and nitrogen balance.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.5
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• pp.659-665
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• 2000

A nitrogen (N) balance trial was conducted to examine the effect of N deprivation on subsequent N retention, blood urea nitrogen (BUN) and IGF-I levels and the ratio of IGF binding protein (IGFBP)-3 to IGFBP-l and -2. Pigs in treatment (T) 1 were given diet A (2.39% N) and those in T2 and T3 were given diet B (1.31% N) and excreta were collected (period 1 (P1)). Pigs in T1 continued to receive diet A while diets for T2 and T3 were changed to diets A and C (2.74% N), respectively. The excreta were collected for two more periods (P2 and P3). During P1, pigs in T2 and T3 retained 50% less N (p<0.001) than those in T1. However, pigs provided T2 (p<0.01) and T3 (p<0.05) retained more N than those assigned to T1 during P2. Pigs in T3 tended to retain more (p=0.10) N than those receiving T2 for the same period. The BUN values were lower (p<0.05) for pigs assigned to T2 and T3 than T1 during P1 and P2. Both IGF-I and IGFBP ratios of pigs assigned to T1 were higher (p<0.05) than those given T2 and T3 during P1 but no differences were found during P2 and P3.

• Proceedings of the KWS Conference
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• 1998.05a
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• pp.150-154
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• 1998

The purpose of this paper is to investigate optimum welding conditions of STS 304 thin sheet by GTA welding and control 6 $\delta$--fenite which is harmful in mechanical processing, corrosion problem and can be formed brittle a phase in using long term at high temperature. One series of automatic welds was made using argon plus 10, 20, 30 % nitrogen to ensure a fully austenite deposit. Results obtained were summarized as follows: 1) 6 $\sigma$ferrite content in the weld metals is influenced largely by the nitrogen content. 2) Additions of nitrogen to the shielding gas can significantly reduce the amount of retained delta ferrite and result in an increase in hot cracking. 3) Bead width was increased when Ar + $N_2$ shielding gas was used and travel speed was increased. 4) Ar+$N_2$ shielding gas made weld metal ductile and reduce 6 -$\delta$-ferrite.

• Journal of Animal Science and Technology
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• v.47 no.3
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• pp.419-428
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• 2005

This study was carried out to investigate the effect of replacing dried mugwort (Artemisia montana Pampan) in concentrate a time of preparation pellet. The treatments, arranged in a 4${\times}$4 Latin square design, were four additional levels of mugwort at 0, 3, 5 and 10% in concentrate. Four crossbred (CorriedalexPolwarth, t) sheep with a mean body weight of 41.3 kg were used to evaluate nutrients digestibility, palatability, fermentation characteristics and microbial protein synthesis in the rumen. The digestibility of crude protein was improved (p < 0.05) to 6.1 % - 8.6 % in sheep fed 3, 5 and 10% mugwort pellet treatments compared with that of control. That of crude fat and NDF was improved (p < 0.05) to 5.8 % - 7.3 % in sheep fed 3 % compared to other treatments. The ruminal pH was significantly (p < 0.05) decreased in sheep fed 3 % mugwort pellet compared to other treatments when observed at 0.5 hour after feeding. The ammonia nitrogen concentrations were the highest in sheep fed all treatments at 1 hour after feeding. The ruminal concentrations of acetic acid and propionic acids were an improvement (p < 0.05) at the 3% and 5% treatments. Retained nitrogen of 3, 5 and 10% treatment with the value of 2.24 - 2.82 g was higher (p < 0.05) than that of the control with 0.78 g and microbial protein production of 10% treatment was higher (p < 0.05) than that of control. This study suggested that the replacing with 3% dry mugwort (Artemisia montana Pampan) in concentrate a time of preparation pellet will improve nutrient digestibility, palatability, ruminal fermentation characteristics and feed value.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.3
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• pp.396-400
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• 2002

This study was conducted to evaluate the dry matter (DM) yield, quality and utilization of nutrients in Korean lespedeza (Lespedeza stipulacea Maxim.) swards as a roughage source. DM yield in various stages, chemical composition, and DM digestibility were observed, and DM intake, digestibility and utilization of nitrogen and energy by Korean native goat were determined. Experimental diets include three treatments: mixture hay (MH) 100%, MH (80%)+wild Korean lespedeza hay (LH) 20% and MH (60%)+LH (40%). As growth stage advanced, the DM yield of Korean lespedeza tended to increase significantly (p<0.05). The mean DM yield of all growing stages was observed as 7,336 kg/ha. Crude protein (CP) content of Korean lespedeza tended to decrease, but fibrous contents tended to increase when the growth stage advanced. The tannin content of Korean lespedeza was the highest at the bud stage (64.7 mg/g). However, it showed a tendency to decrease as the growth stage advanced, and thus it was the lowest at the ripe seed stage (26.8 mg/g) (p<0.05). With increasing level of LH, voluntary DM intake by Korean native goats slightly increased, but no differences were observed between diets. The digestibility of DM, cellular constituents and NDF was slightly higher in LH containing diets than that of MH 100% diet (p<0.05). There was no significant difference in apparently digested N% among all diets, but retained N% and retained N% of the absorbed were higher in MH (60%)+LH (40%) than those of other diets (p<0.05). A difference in the utilization of energy was not detected. In conclusion, Juvenile LH improved the digestibility of nutrients, presumably due to its high CP content and low fibrous compound. Especially, tannin in LH did not affect in DM intake, but increased the nitrogen utilization of Korean native goats. Accordingly, it could be suggested that Korean lespedeza has a potential to be provided as a roughage source for Korean native goats.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.12
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• pp.1726-1731
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• 2013

The effects of different dietary electrolyte balance (DEB) on growth performance, nitrogen (N) metabolism and some blood biochemical parameters were investigated in 2 to 3 months old growing rabbits. A total of 150 growing rabbits of 2 months age were randomly divided into five groups according to average body weight, with 30 rabbits in each group. The DEB levels of the five experimental diets were -154, -3.16, +201, +347, and +500 meq/kg of dry matter (DM), respectively. There was a 7-d adaptation period and a 23-d experimental period. The results showed that the DEB levels had a quadratic affect on the average daily feed intake (ADFI) (p<0.001). The greatest ADFI was achieved when the DEB level was +201 meq/kg DM. Fecal N (FN) content linearly decreased (0.047), while digestible N (DN), retained N (RN), efficiency of intake N converted into digestible N (DN/IN) and the efficiency of intake N converted into retained N (RN/IN) linearly increased with the DEB increase (0.020, 0.004, 0.021, and 0.049, respectively). Serum phosphorus (P) ion content linearly increased with the DEB increase (p = 0.036). The DEB had a quadratic relationship with serum anion gap (AG) (p = 0.002) and serum parathyroid hormone (PTH) content (p = 0.016). The DEB levels quadratically affected base excess (BE) in the plasma (p<0.001). In conclusion, the DEB unaffected growth performance but affected feed intake, N metabolism and some blood biochemical parameters of growing rabbits.