• 한국농공학회논문집
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• 제63권1호
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• pp.89-102
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• 2021

Soils in agricultural lands contain large amount of organic matter and nutrients due to the injected fertilizers and manure. During heavy rain, surface water and base runoff pollutants flows into a nearby stream or lake with eroded soil from agricultural lands. On the other hands, agricultural lands near the lake are inundated due to the increase of the water level in the lake, leading to organic matter and nutrient release from the inundated soil. In this study, releasing rates of nutrient salts and organic substances were analyzed for the soil in the agricultural land, where cultivation activities has been carried out and periodically flooded, to account for the possibility of contamination from the inundated agricultural land in reservoir areas The experiment results have shown that COD was released from the soil in anaerobic conditions, and T-P was released in both anaerobic and aerobic conditions. However, in the case of T-N, it was found that the runoff by soil was not made before the rainfall occurred, and when the soil was impound due to rainfall, the elution occurred under the aerobic conditions. Through the results of this study, it was possible to account for the effect of flooded agricultural lands on the water quality in the lake, and this could be reflected in an efficient agricultural non-point pollution management policy. In order to determine the precise releasing rate for each agricultural land, it is believed that the leaching experiment for paddy fields and grasslands are needed.

• 대한환경공학회지
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• 제29권2호
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• pp.169-175
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• 2007

B3(Bio Best Bacillus)와 RABC(Rotating Activated Bacillus Contactor) 공법은 Bacillus를 이용하여 유기물뿐만 아니라 질소와 인도 효율적으로 제거하는 공법이다. 그러나 현 단계에서 폐수처리 시설에 이용되고 있는 Bacillus의 유기물 제거에 대한 미생물학적인 특성을 과학적으로 입증하지 못하였다. 이에 본 연구에서는 활성슬러지에서 보고되는 균주 Burkholderia cepacia(KCTC 2966)를 대조균으로 하고 Bacillus megaterium(KCTC 3007), Paenibacillus polymyxa(KCTC 3627) 균주와 B3 공법의 분뇨처리장으로부터 분리한 Bacillus속 4개 균주 Bacillus sp.(A12, C21, F12, L1)를 선정하여 0.2% Nutrient Broth, $30^{\circ}C$에서 배양하면서 Burkholderia의 Bacillus의 유기물 제거능력을 비교하였다. 접종량에 따른 개체군 차이로 유기물 제거능력이 영향 받을 수 있지만, Bacillus의 유기물 제거능력이 Burkholderia보다 $2\sim5$배 뛰어남을 알 수 있었다. 또한, Bacillus megaterium과 Bacillus sp.(C21, F12, N12)의 영양세포와 내생포자의 유기물 제거능력의 차이를 알아본 결과 내생포자의 제거능력이 영양세포보다 더욱 뛰어남을 알 수 있었다.

• 한국습지학회지
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• 제23권1호
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• pp.35-43
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• 2021

도시지역의 강우유출수를 관리하기 위하여 자연기반해법의 LID 및 그린인프라 적용이 늘고 있다. 식물이 LID 시설에 적용되는 이유는 광합성을 이용하여 오염물질 저감효율을 높이고, 시설 내부 오염물질 축적을 줄여 유지관리 기능을 향상시키기 위해서이다. 그러나 LID 시설 내부에서 작용하는 식물의 오염물질 흡입능력의 불확실성으로 인하여 식재 선정시 어려움이 많다. 따라서 본 연구는 도로변, LID 시설 및 조경공간에 식재되어있는 식물의 건물률 및 영양물질 함량을 비교하여 오염물질 제거기작을 분석하기 위해 수행되었다. 실험대상인 7종의 초본류, 관목류 및 교목류의 월별 건물률은 60~90% 범위를 보였다. 초본류 몸체 내 TN 함량은 여름철까지 지속적으로 성장하다가 감소하는 추세를 보였다. 그러나 관목류와 교목류는 초봄과 늦여름에 높은 TN 함량을 보였다. 패랭이를 제외한 LID 시설에 식재된 모든 식물에서 높은 TP 함량을 보였다. 이는 LID의 식물이 인 제거에 효율적이라는 것을 의미한다. 식물별 영양염류 함량은 유입수 농도에 영향을 끼치는 도시환경에 크게 의존하는 것으로 나타났다. 따라서 이러한 결과들은 향후 LID 적용 시 식생 선정에 있어 유용한 자료로 활용 가능할 것으로 판단된다.

• Journal of Ecology and Environment
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• 제43권1호
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• pp.14-21
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• 2019

Background: Stoichiometry plays an important role in understanding nutrient composition and cycling processes in aquatic ecosystems. Previous studies have considered C:N:P ratios constant for both DOM (dissolved organic matter) and POM (particulate organic matter). In this study, water samples were collected in the six major rivers in Korea and were incubated for 20 days. C:N:P ratios were determined during the time course of the incubations. This allowed us to examine the changes in N and P contents of organic matter during decomposition. Results: POM and DOM showed significant differences in N and P content and the elemental ratios changed during the course of decomposition; DOM showed higher C:N and C:P ratios than POM, and the C:N and C:P ratios increased during decomposition, indicating the preferential mineralization of P over N and N over C. Conclusions: The N and P contents of organic matter in aquatic ecosystem are far from constant and vary significantly during decomposition. More detailed information on the changes in C:N:P ratios will provide improved understanding of decomposition processes and improved modeling of aquatic ecosystems.

• Asian-Australasian Journal of Animal Sciences
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• 제26권7호
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• pp.981-986
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• 2013

The nutrient digestibility, nitrogen balance and in vivo metabolizable energy supply of Mucuna pruriens whole pods fed to growing Pelibuey lambs was investigated. Eight Pelibuey sheep housed in metabolic crates were fed increasing levels of Mucuna pruriens pods: 0 (control), 100 (Mucuna100), 200 (Mucuna200) and 300 (Mucuna300) g/kg dry matter. A quadratic (p<0.002) effect was observed for dry matter (DM), neutral detergent fibre (aNDF), nitrogen (N) and gross energy (GE) intakes with higher intakes in the Mucuna100 and Mucuna200 treatments. Increasing M. pruriens in the diets had no effect (p>0.05) on DM and GE apparent digestibility (p<0.05). A linear reduction in N digestibility and N retention was observed with increasing mucuna pod level. This effect was accompanied by a quadratic effect (p<0.05) on fecal-N and N-balance which were higher in the Mucuna100 and Mucuna200 treatments. Urine-N excretion, GE retention and dietary estimated nutrient supply (metabolizable protein and metabolizable energy) were not affected (p>0.05). DM, N and GE apparent digestibility coefficient of M. pruriens whole pods obtained through multiple regression equations were 0.692, 0.457, 0.654 respectively. In vivo DE and ME content of mucuna whole pod were estimated in 11.0 and 9.7 MJ/kg DM. It was concluded that whole pods from M. pruriens did not affect nutrient utilization when included in an mixed diet up to 200 g/kg DM. This is the first in vivo estimation of mucuna whole pod ME value for ruminants.

• Asian-Australasian Journal of Animal Sciences
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• 제29권2호
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• pp.204-210
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• 2016

This study examined the effect of supplementing exogenous cellulase on nutrient and energy utilization. Twelve desexed Boer crossbred goats were used in a replicated $3{\times}3$ Latin square design with 23-d periods. Dietary treatments were basal diet (control, no cellulase), basal diet plus 2 g unitary cellulase/kg of total mixed ration dry matter (DM), and basal diet plus 2 g compound cellulase/kg of total mixed ration DM. Three stages of feeding trials were used corresponding to the three treatments, each comprised 23 d, with the first 14 d as the preliminary period and the following 9 d as formal trial period for metabolism trial. Total collection of feces and urine were conducted from the 4th d of the formal trial, and gas exchange measures were determined in indirect respiratory chambers in the last 3 d of the formal trial. Results showed that cellulase addition had no effect (p>0.05) on nutrient digestibility. Dietary supplementation of cellulase did not affect (p>0.05) N intake and retention in goats. Gross energy (GE) intake, fecal energy and urinary energy excretion, heat production were not affected (p>0.05) by the cellulase supplementation. Total methane emission (g/d), $CH_4$ emission as a proportion of live weight or feed intake (DM, organic matter [OM], digestible DM or digestible OM), or $CH_4$ energy output ($CH_4$-E) as a proportion of energy intake (GE, digestible energy, or metabolizable energy), were similar (p>0.05) among treatments. There was a significant (p<0.001) relationship between $CH_4$ and live weight (y = 0.645x+0.2, $R^2$ = 0.54), $CH_4$ and DM intake (y = 16.7x+1.4, $R^2$ = 0.51), $CH_4$ and OM intake (y = 18.8x+1.3, $R^2$ = 0.51) and $CH_4$-E and GE intake. Results from this study revealed that dietary supplementation of cellulase may have no effect on nutrient digestibility, nitrogen retention, energy metabolism, and methane emission in goat.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1155-1162
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• 2015

This study aimed to evaluate the nutrient digestibility of growing rabbits fed diets with different levels of either Leucaena leucocephala (LLM) or Moringa oleifera (MOLM) leaf meals and also to compare total collection and $TiO_2$ marker methods for estimating digestibility. A total of 30 California growing rabbits ($1.81{\pm}0.19kg$ live weight on average) were randomly distributed into five experimental groups of six rabbits each and were housed in individual cages. The groups were control, 30% LLM, 40% LLM, 30% MOLM, and 40% MOLM. All groups received pelleted diets for two weeks; diets also contained 4 g/kg titanium dioxide as dietary marker. Daily feed intake was recorded during the whole experimental period and total feces were collected daily and weighed individually during four days. The results showed that there were no difference (p>0.05) in feed, dry matter (DM), organic matter (OM), crude protein (CP), digestible energy, and crude fiber (CF) intake between the control group and the other experimental groups. The apparent digestibility values of DM, OM, CP, CF, acid detergent fiber, and gross energy were the highest for control group (p = 0.001), meanwhile MOLM diets had generally higher nutrient digestibility coefficients than LLM diets. Increasing the inclusion level of leaf meal in the diet from 30% to 40% improved the digestibility of CF from 45.02% to 51.69% for LLM and from 48.11% to 55.89% for MOLM. Similar results for apparent nutrient digestibility coefficients were obtained when either total collection or indigestible marker method was used. In conclusion, the digestibility of MOLM containing diets were better than LLM diets, furthermore $TiO_2$ as an external marker could be used as a simple, practical and reliable method to estimate nutrients digestibility in rabbit diets.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.629-632
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• 2004

The objectives of this study were to determine the effects of substituting bread by-product (BBP) for barley grain in high concentrate fattening diets for kids on nutrient intake, growth performance, and nutrient digestibility. Twenty-eight Baladi kids (body weight=17.1${\pm}$1.0 kg) were assigned randomly to 4 experimental finishing diets (7 kids/treatment) in a completely randomized design for 70 days. The control (CON) diet contained 20, 60, 11, 7 and 2% (DM basis) alfalfa hay, barley grain, soybean meal, corn grain, and mineral and vitamin mix, respectively. Bread by-product substituted barley grain by 10, 20 and 30% of the diet DM in the LBBP, MBBP, and HBBP diets, respectively. Dry matter intakes for the CON, LBBP and MBBP diets were similar (p>0.05; avg.=592 g/day), however, kids fed the HBBP diet had a lower (p<0.05) DM intake (451 g/day). Organic matter and CP intakes showed similar patterns to that observed for DM. Dietary treatments did not affect (p>0.05) average daily gain for kids fed the CON, LBBP and MBBP diets (avg.=150 g/day). Final body weights for kids fed the CON, LBBP and MBBP diets (avg. 27.1 kg) were greater (p<0.05) than for kids fed the HBBP diet (23.7 kg). Feed to gain ratio was greater for the CON, LBBP and MBBP diets (avg. 3.9) compared with the HBBP diet (5.0). No significant (p>0.05) effect of the dietary treatment was observed for DM, OM and NDF digestibility. Substituting BBP for barley grain up to 20% of the diet DM did not affect nutrient intake, growth performance and nutrient digestibility of kids and resulted in a decrease in feed cost.

• Asian-Australasian Journal of Animal Sciences
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• 제30권3호
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• pp.370-378
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• 2017

Objective: An experiment was conducted to investigate the effects of a specific mixture of essential oils (MEO), containing thyme, clove and cinnamon EO, on rumen microbial fermentation, nutrient apparent digestibility and blood metabolites in fistulated sheep. Methods: Six sheep fitted with ruminal fistulas were used in a repeated measurement design with two 24-d periods to investigate the effect of adding MEO at 0 (control), 0.8, and 1.6 mL/d on apparent nutrient digestibility, rumen fermentation characteristics, rumen microbial population and blood chemical metabolites. Animals were fed with a 50:50 alfalfa hay:concentrate diet. Results: Ruminal pH, total volatile fatty acids (VFA) concentration, molar proportion of individual VFA, acetate: propionate ratio and methane production were not affected with MEO. Relative to the control, Small peptides plus amino acid nitrogen and large peptides nitrogen concentration in rumen fluid were not affected with MEO supplementation; while, rumen fluid ammonia nitrogen concentration at 0 and 6 h after morning feeding in sheep fed with 1.6 mL/d of MEO was lower (p<0.05) compared to the control and 0.8 mL/d of MEO. At 0 h after morning feeding, ammonia nitrogen concentration was higher (p<0.05) in sheep fed 0.8 mL/d of MEO relative to 1.6 mL/d and control diet. Ruminal protozoa and hyper ammonia producing (HAP) bacteria counts were not affected by addition of MEO in the diet. Relative to the control, no changes were observed in the red and white blood cells, hemoglobin, hematocrit, glucose, beta-hydroxybutyric acid, cholesterol, total protein, albumin, blood urea nitrogen and aspartate aminotransferase and alanine aminotransferase concentration. Apparent total tract digestibility of dry matter, crude proten, organic matter, and neutral detergent fiber were not influenced by MEO supplementation. Conclusion:The results of the present study suggested that supplementation of MEO may have limited effects on apparent nutrient digestibility, ruminal fermentation and protozoa and HAP bacteria count, blood cells and metabolites.

• Journal of Animal Science and Technology
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• 제58권9호
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• pp.34.1-34.9
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• 2016

Background: By-products of pickled radish (BPR) are considered food waste. Approximately 300 g/kg of the total mass of raw materials becomes BPR. Production of pickled radish has grown continuously and is presently about 40,000 metric tons annually in Korea. The objective of the present study was thus to explore the possibility of using BPR as a ruminant feed ingredient. Results: BPR contained a large amount of moisture (more than 800 g/kg) and ash, and comprised mostly sodium (103 g/kg DM) and chloride (142 g/kg DM). On a dry matter basis, the crude protein (CP) and ether extract (EE) levels in BPR were 75 g/kg and 7 g/kg, respectively. The total digestible nutrient (TDN) level was 527 g/kg and the major portion of digestible nutrients was carbohydrate; 88 % organic matter (OM) was carbohydrate and 65 % of total carbohydrate was soluble or degradable fiber. The coefficient of variation (CV) of nutrient contents among production batches ranged from 4.65 to 33.83 %. The smallest CV was observed in OM, and the largest, in EE. The variation in CP content was relatively small (10.11 %). The storage stability test revealed that storage of BPR at $20^{\circ}C$ (room temperature) might not cause spoilage for 4 d, and possibly longer. If BPR is refrigerated, spoilage can be deferred for 21 d and longer. The in vitro ruminal fermentation study showed that substitution of annual ryegrass straw with BPR improved ruminal fermentation, as evidenced by an increase in VFA concentration, DM degradability, and total gas production. Conclusion: The major portion of nutrients in BPR is soluble or degradable fiber that can be easily fermented in the rumen without adverse effects, to provide energy to ruminant animals. Although its high sodium chloride content needs to be considered when formulating a ration, BPR can be successfully used as a feed ingredient in a ruminant diet, particularly if it is one component of a total mixed ration.