• Fisheries and Aquatic Sciences
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• v.23 no.5
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• pp.12.1-12.8
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• 2020

Background: An 8-week feeding trial was designed to evaluate the potential of yellow mealworm (MW; Tenebrio molitor) as a locally available nutrient-rich feedstuff for rainbow trout fry (Oncorhynchus mykiss). Methods: Triplicate groups of fish (mean ± SE; 1.11 ± 0.01 g) were assigned to each of the five isonitrogenous and isocaloric practical diets containing graded level of a full fat MW (0, 7, 14, 21, and 28%) at the expense of fish meal (designated as MW0, MW7, MW14, MW21, and MW28, respectively). Results: Fish growth performance in terms of weight gain and specific growth rate significantly increased with increasing dietary MW level up to 14% and then declined when dietary MW levels further increased to 28%. Significantly higher protein efficiency ratio and lower feed conversion ratio were found in fish fed with diets containing MW compared to fish fed the control MW0. Myeloperoxidase activity was significantly higher in fish fed MW7 diet compared to fish fed the MW0 diet. Fish fed the MW14 and MW28 diets had significantly higher lysozyme activities than those fed the MW0 diet. Conclusions: Overall, the efficacy of MW as promising alternative to fish meal in practical diets for rainbow trout fry has been proved not only in relation to growth rates and feed utilization, but also from the viewpoint of immunopotentiation effects.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.8
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• pp.1157-1163
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• 2005

An experiment was conducted to study the effect of replacing soyabean meal (SBM) at 50 and 100% with conventional (CMC) and low glucosinalate mustard cakes (LGMC) in iso-caloric and iso-nitrogenous diets in broiler chickens. All these diets contained 0.1% choline chloride with a purity of 50% (w/w). Another diet was prepared by replacing SBM in toto with CMC with no supplemental choline to find out the possible role of supplemental choline in mustard cake (MC) based diets. Two hundred and seventy day-old broiler chicks were distributed randomly in 54 stainless steel battery brooder pens of five chicks in each pen. Each experimental diet was allotted at random to nine battery brooders and offered ad-libitum from day 2 through 42 days of age. Body weight gain was significantly depressed by total replacement of SBM with either LGMC or CMC at 21 days of age. Non-supplementation of choline significantly depressed the growth compared to those fed CMC 100% with supplemental choline. However, at 42 days of age, such an effect was seen only with CMC. Replacement of SBM with CMC 100% with or without choline supplementation depressed the body weight gain. The concentrations of cholestorol and tryglicerides in serum and the relative weights of ready to cook yield, giblet and gizzard decreased by incorporation of mustard cakes in broiler diets. The trend in fat and protein contents in breast and thigh muscles and liver was not clearly attributable to the treatment effect. Based on the results, it is concluded that SBM can be replaced in toto with LGMC (535.0 and 466.5 g/kg starter and finisher diets, respectively) or up to 50% (215.0 and 186.7 g/kg starter and finisher diets, respectively) with CMC in commercial broiler chicken diets. Choline supplementation at 0.1% level in broiler diets containing CMC was found to be beneficial during starter phase.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.2010-2018
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• 2017

Mixotrophic microalgal growth gives a great premise for wastewater treatment based on photoautotrophic nutrient utilization and heterotrophic organic removal while producing renewable biomass. There remains a need for a control strategy to enrich them in a photobioreactor. This study performed a series of batch experiments using a mixotroph, Chlorella sorokiniana, to characterize optimal guidelines of mixotrophic growth based on a statistical design of the experiment. Using a central composite design, this study evaluated how temperature and light irradiance are associated with $CO_2$ capture and organic carbon respiration through biomass production and ammonia removal kinetics. By conducting regressions on the experimental data, response surfaces were created to suggest proper ranges of temperature and light irradiance that mixotrophs can beneficially use as two types of energy sources. The results identified that efficient mixotrophic metabolism of Chlorella sorokiniana for organics and inorganics occurs at the temperature of $30-40^{\circ}C$ and diurnal light condition of $150-200{\mu}mol\;E{\cdot}m^{-2}{\cdot}s^{-1}$. The optimal specific growth rate and ammonia removal rate were recorded as 0.51/d and 0.56/h on average, respectively, and the confirmation test verified that the organic removal rate was $105mg\;COD{\cdot}l^{-1}{\cdot}d^{-1}$. These results support the development of a viable option for sustainable treatment and effluent quality management of problematic livestock wastewater.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.19-26
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• 2007

The lab-scale BNR processes fed with Municipal Wastewater Before or After Primary Clarifier (MWBPC or MWAPC) were operated to observe the behavior of particle organic matter in terms of nitrification and denitrification efficiency. As a result of the fractionation of the COD from MWBPC or MWAPC using an aerobic respirometric serum bottle reactor, the total mass of biodegradable organic matter from MWBPC is about 52% greater than the mass from MWAPC. Batch reactors were operated to observe the effect of the Particulate Organic Matter (POM) on substrate utilization for denitrification. Although the consumption of POM for denitrification was observed, the increment of the Specific Denitrification Rate (SDNR) was not great. In terms of the effect of POM on nitrification at different HRTs, activate sludge reactors were operated to determine the optimal HRT when MWBPC and MWAPC were fed relatively. All reactors showed a great organic matter removal efficiency. Reactors fed with MWAPC had obtained the nitrification efficiency above 90% when the HRT of 4 hr, at least, was maintained, while reactors fed with MWBPC had same efficiency when the HRT longer than 5 hr was kept. Three parallel $A^2/O$ systems fed with MWBPC or MWAPC relatively were operated to investigate the effects of POM on BNR processes with varying the HRT of an anoxic reactor. For all systems, the efficiency of organic matter removal and denitrification, respectively, was great and about the same. In case of denitrification efficiency, system with MWAPC had 1.5% lower than system with MWBPC at the same HRT of anoxic reactor of 2 hr, and the increasing the HRT of the anoxic reactor by 1 hr in systems fed with MWBPC resulted in a 3.5% increment. The denitrification rate was similar while the consumption of organic matter in systems fed with MWBPC was higher than system fed with MWBPC. It suggests that POM in MWBPC was not be used significantly as a substrate for denitrification in system with the HRT of 3 hr of an anoxic reactor.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.4
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• pp.272-278
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• 2001

To investigate of C and N metabolisms in response to phosphorus-deficient stress during regrowth of Italian ryegrass (Lolium multiflorum L.), C and N metabolites were analyzed at 0, 6, 12 and 24 days after defoliation. P-sufficient (control, +P) and P-absent (-P) nutrient solutions were applied from 7 days before defoliation, and continued for one cycle of 24 day-regrowth period. During 24 days of regrowth, dry matter of regrowing shoots and remaining tissues were not significantly different between +P and -P treatment. In remaining stubble, 70% to 91 % decline of the initial level (at day 0) in all C compounds occurred during the first 6 days of regrowth. Initial amounts of nitrate and amino acids in roots were significantly higher in the +P medium. Nitrate contents in stubble in the +P medium significantly decreased for the first 12 days and then rapidly recovered, while that of the -P medium continuously decreased until day 24. Amino acids in stubble in the P medium were continuously increased during the whole regrowth period. Soluble proteins in stubble in the +P medium also largely fell down (46.0% of the initial) for only the first 6 days, however the decline in the -P medium continued until day 12. In regrowing shoots, the accumulation of C compounds was significantly higher, while that of N compounds except amino acids was largely lower in the -P medium. These results showed a stimulation of carbohydrate synthesis and a compensatory utilization of organic reserves occurred to support regrowth under P-deficient condition.

• Korean Journal of Agricultural Science
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• v.45 no.2
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• pp.219-228
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• 2018

This study evaluated the effects of glycerol polyethylene glycol ricinoleate (GPGR) supplementation in different energy density diets on the growth performance, blood profiles, excreta gas emission, and total tract apparent retention (TTAR) of nutrients in broilers. A total of 544 one-day-old male Ross broilers were used in a 35-day trial. The broilers were allocated into one of four treatment groups in a $2{\times}2$ factorial arrangement with two levels of energy densities (a normal energy or decreased energy density) and GPGR (0 and 0.035%). From day 18 to 35, the GPGR supplemented and normal energy density diet groups showed a significantly improved (p < 0.05) body weight gain (BWG). Meanwhile, the GPGR supplemented diet group had a significantly reduced (p < 0.05) feed conversion ratio (FCR) compared to that of the non-supplemented diet group. From day 0 to 35, the GPGR supplemented diet and the normal energy density diet groups had a significantly increased (p < 0.01) BWG and a reduced (p < 0.01) FCR. Moreover, GPGR supplementation tended to increase (p < 0.1) the TTAR of the dry matter (DM) compared with the non-supplemented diets. Likewise, the normal energy density diets had a significantly improved TTAR for the gross energy (GE) (p < 0.05) than that of the decreased energy density diets. No interactive effects were observed between the energy density and GPGR supplemented diets. In conclusion, both dietary GPGR supplementation and normal energy density diets had beneficial effects on the growth performance of broiler chickens without any adverse effects on blood profiles and excreta gas emission.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.180-186
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• 1998

A 10-week feeding experiment was conducted to determine the phosphorus requirement of juvenile Korean rockfish (Sebastes schlegeli). Three replicate groups of fish initially averaging 4.2g were fed the semipurified experimental diets containing graded levels of $NaH_2PO_4\;\cdot\;2H_2O$ to provide from $0.1\%$ to $1.32\%$ total phosphorus level in a flow-through seawater system. Korean rockfish muscle and casein were used as the protein sources of the basal diet. Weight gain, feed efficiency and protein retention of fish fed the $0.35\%$ phosphorus were higher than those of fish fed the $0.1\%$ phosphorus, although no significant improvements $(P>0.01)$ were observed above the level. Determined phosphorus requirement using the broken line model was found to be $0.3\%$ for weight gain. Moisture, protein and lipid contents of whole body and muscle were not affected by dietary phosphorus levels $(P>0.01)$. Lipid contents of liver in fish fed the $0.1\%$ phosphorus were lower than those in fish fed the $0.35\%$ and $1.32\%$ phosphorus $(P<0.01)$. Dietary phosphorus increased ash and phosphorus contents of the whole body, while those of bone were not affected $(P>0.01)$. The data obtained in this study indicate that a $0.3\%$ dietaryphosphorus level could be recommended for the optimum growth and efficient nutrient utilization of juvenile Korean rockfish.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.7-15
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• 2002

The essential oil free needles, which were left after distillation of essential oil from various coniferous needles, were fermented with food waste organics in order to use as compost and roughage. Microorganisms for the fermentation were selected from domestic sources such as swine compost, bark compost, and kimchi, etc, and consisted of aerothermophilic bacteria and actinomycetes. The weight reduction ratio of food waste organics treated with the microorganisms was 90% after 30 days treatment, and the fermentation temperature was kept at approximately $45^{\circ}C$. The compost process was really slow due to chemical compounds derived from needles, and it finally took 60 days for complete compost. When 10% of needle compost was mixed with soil for radish growth, the growth indicators such as leaf length and root weight were increased compared with control, while root weight, root width, and root length were inhibited on the addition of 20% needle compost. The nutrient value and digestibility ratio of various essential oil free needles as roughage for ruminant animals were evaluated. The ratio of crude protein for essential oil free needles from Korean pine(Pinus koraiensis) was 10.02%, which was higher than those of rice straw(5.48%) and corn(9.00%). The digestibility ratios of essential oil free needles from Sawara cypress(Chamaecwaris pislfera), Korean pine(Pinus koraiensis), and Japanese Red Pine(Pinus densiflora) was 53%, 34%, 34%, respectively, indicating that those essential oil free needles were considered as excellent roughage.

• Journal of Ecology and Environment
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• v.43 no.4
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• pp.461-468
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• 2019

Background: This study aimed to identify NO₃^--N sources using the stable isotope δ¹⁵N in Chydorus sphaericus (OF Müller), to investigate hydrological characteristics and nutrient states in artificial wetlands near the Nakdong River. Chydorus sphaericus is dominant in wetlands where aquatic plants are abundant, occurring in high density, and is sensitive to wetland water pollution, making it suitable for identification of NO₃^--N sources. Results: NO₃^--N sources for each wetland were strongly dependent on hydrological characteristics. Wetlands with sewage or rainfall/groundwater as their main sources had high levels of NO₃^--N, whereas wetlands with surface water as their main input had comparatively lower levels. Since wetlands with sewage and rainfall/groundwater as their main water sources were mostly detention ponds, their inputs from tributaries or the main river stream were limited and nutrients such as NO₃^--N easily become concentrated. Changes in NO₃^--N levels at each wetland were closely associated with δ¹⁵N of C. sphaericus. Interestingly, regression analysis also showed positive correlation between δ¹⁵N of C. sphaericus and NO₃^--N level. Conclusions: We conclude that the nitrate stable isotope (δ¹⁵N) of C. sphaericus can be used to elucidate the hydrological characteristics of riverine wetlands. This information is important for maintenance and conservation of artificial wetlands at the Nakdong River.

• KSBB Journal
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• v.9 no.2
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• pp.200-210
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• 1994

In batch bioreactor fermentations for cyclosporin A (CyA) production, good potential for bioprocess improvement was demonstrated in the immobilized cell system, providing appreciably better utilization of the catalytic activity of the biomass than the freely suspended cells, especially during the exponential phase. When concentrated nutrient medium was added pulsely during the exponential phase of cell growth(at hour 139 of fermentation), reactivation and regermination in both immobilized and suspended cell cultures were observed to contribute to the longevity of CyA production, maintaining maximum CyA titre until 250 hours of fermentation. Contrarily, simple batch fermentations without any supplement of medium in both systems showed repid decrease in CyA concentrations during the late stationary phase. Notably, the CyA yield coefficient $(Y_p/x)$ for the immobilized cell system was maintained quite high even after the pulse addition of the concentrated full medium, reaching almost 80% of the level attained during the exponential phase. This is in sharp contrast when compared with the corresponding value of 58% in the case of parallel-suspended cells. This pattern of CyA production resulted in considerably enhanced CyA production in the immobilized cell system, reaching almost 2 time higher maximum CyA production in comparison with the free cell system.