• 한국토양비료학회지
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• 제49권4호
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• pp.401-408
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• 2016

The present study described the isolation of 2-methylbutyric acid (2-MBA) produced from Bacillus pumilus L1, to subsequently investigate its nematicidal activity for the control of the root-knot nematode. The results showed that 2-MBA could be purified by chromatographic techniques and was identified using nuclear magnetic resonance and liquid chromatography-mass spectrometry. Crude extract and partially purified compounds had a significant effect on the inhibition of egg hatchability and second-stage juvenile (J2) mortality. A dose-dependent effect of 2-MBA was observed for J2 mortality and egg hatchability. Egg hatchability was 69.2%, 59.9%, 32.7%, and 0.0% at 125, 250, 500, and $1000{\mu}g\;mL^{-1}$ of 2-MBA after 4 d of incubation, respectively. Meanwhile, J2 mortality was in the range of 24.4%-100.0% after 2 d of incubation, depending on the concentrations of 2-MBA used. A pot experiment also demonstrated that treatment of B. pumilus L1 culture caused a significant reduction in the number of galls, egg masses, and J2 population than that of the tap water (TW) control. However, as the B. pumilus L1 culture concentration was decreased, the efficacy of nematode control by treatment of B. pumilus L1 culture was reduced compared to that of TW. B. pumilus L1 inoculation at different concentrations also promoted cucumber plant growth. Therefore, our study demonstrated the potential of 2-MBA from B. pumilus L1 as a biocontrol agent against the root-knot nematode and a plant growth promoter for cucumber plants.

• Fisheries and Aquatic Sciences
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• 제12권4호
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• pp.311-316
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• 2009

A 10-week feeding trial with four dietary protein levels (22%, 32%, 42% and 52%) and two dietary lipid levels (8% and 17%) was conducted to investigate the optimum dietary protein and lipid levels for growth of long-nosed barbel fingerlings. Survival rate of fish was not affected by either the dietary protein or the dietary lipid level. Weight gain and feed efficiency were affected by the dietary protein level (P<0.01), but not by the lipid level, and increased with the dietary protein level at the both lipid levels. Weight gain and feed efficiency of fish fed the 52% protein diets with 8-17% dietary lipids were not significantly different from those of fish fed the 42% protein diets with 8-17% dietary lipids and 32% protein diet with 17% dietary lipid. Daily feed intake of fish was not affected by either dietary protein or dietary lipid level. Protein efficiency ratio and protein retention rate of fish fed the 32% protein diet with 17% dietary lipid were significantly higher than those of fish fed the 52% protein diets with 8-17% dietary lipids. Moisture content of fish fed the diets containing 8% lipid were higher than those of fish fed the diets containing 17% dietary lipid at each protein level. Crude lipid content of fish fed the diets containing 17% dietary lipid were higher than that of fish the fed the diet containing 8% dietary lipid at each protein level. The results of this study indicated that 32% protein and 17% lipid could be the optimum dietary level for growth of juvenile long-nosed barbel.

• Asian-Australasian Journal of Animal Sciences
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• 제28권5호
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• pp.647-653
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• 2015

A 12-wk feeding trial was conducted to evaluate the essentiality of choline supplementation in diets for parrot fish. Five isonitrogenous and isocaloric diets were supplemented with 0 (as control), 500, 1,000, and 2,000 mg choline per kg diet, and a positive control diet without choline contained 0.3% of 2-amino-2-methyl-1-propanol as choline biosynthesis inhibitor (designated as Con, C500, C1000, C2000 and $Con^+$, respectively). Triplicate groups of fish (body weight, $8.8{\pm}0.01g$) were fed one of the experimental diets at a rate of 4% body weight twice daily. The fish fed $Con^+$ diet revealed significantly lower growth performance and feed utilization efficiency than other fish groups. Supplementation of choline to the basal diet did not significantly influence fish growth. The highest liver lipid content was observed in fish fed the $Con^+$ diet and inversely correlated with liver choline concentration although the differences were not significant. Also, significantly higher liver linoleic, eicosapentaenoic and docosahexaenoic acid contents were found in fish fed the $Con^+$ diet. Innate immune parameters including respiratory burst and myeloperoxidase activities were not significantly affected by dietary choline levels. The findings in this study conclude that choline concentration of approximately $230mgkg^{-1}$ diet meets the requirement of parrot fish.

• Fisheries and Aquatic Sciences
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• 제14권4호
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• pp.371-378
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• 2011

Juvenile red seabream (mean body weight 29.0 g) were reared in recirculating culture systems with three different biofilter media, sand (SF), polystyrene microbeads (PF), and Kaldnes beads (KF). The efficiencies of the three different biofilter media were also tested. The SF was fluidized, and the PF and KF were trickled. All treatments were duplicated. The volumetric removal rates of total ammonia nitrogen by SF, PF, and KF were 193.8, 183.9, and 142.6 g $m^{-3}day^{-1}$, respectively, and those of nitrite nitrogen ($NO_2$-N) were 113.4, 105.9, and 85.8 g $m^{-3}day^{-1}$, respectively. The TAN and $NO_2$-N removal rates of KF were lower than those of SF and PF (P < 0.05), but there was no significant difference in these rates between SF and PF (P > 0.05). Among the biofilters used, only KF showed total suspended solid (TSS) removal capacity. The TSS removal efficiencies of SF and PF were negative. The growth rates of fish in SF were significantly higher than those in KF but not higher than those in PF. There was no difference in growth rate between fish in PF and KF. The specific growth rate and feed conversion efficiency of red seabreams in KF were lower than those in SF and PF, but there were no significant differences between SF and PF. These results indicate that sand and polystyrene microbeads are recommended for red seabream culture in a recirculating system.

• Fisheries and Aquatic Sciences
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• 제13권4호
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• pp.284-293
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• 2010

To reduce anti-nutritional factors in plant protein sources for fish meal replacement in fish feeds, cottonseed and soybean meal (CS) were fermented with Aspergillus oryzae. A feeding trial was conducted to verify the effects of fermented CS (FCS) with phytase supplementation on gossypol detoxification, phosphorus digestibility, antioxidant activity, and growth performance of juvenile olive flounder over 10 weeks. Four diets were formulated to replace 0, 30, or 40% fish meal protein with CS or FCS (designated as CS0, CS30, FCS30P, and FCS40P). Phytase (1,000 FTU/kg) was added to FCS30P and FCS40P. The microbial fermentation significantly increased dietary total polyphenols and consequently led to higher DPPH radical-scavenging activities in fish feed and fish tissue. Dietary and liver gossypol concentrations were dramatically decreased by the fermentation process. Phosphorus digestibility was significantly increased in fish fed the FCS40P diet. However, growth performance decreased in fish fed FCS diets. This study demonstrates that the fermentation process and phytase supplementation can improve the phosphorus availability of plant protein sources in fish. The fermentation of CS by A. oryzae could increase antioxidant activities in feed and fish and effectively degrade toxic gossypol in cottonseed meal.

• 한국발생생물학회지:발생과생식
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• 제18권4호
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• pp.233-240
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• 2014

The early growth response protein 1 (Egr-1) is a widely reported zinc finger protein and a well known transcription factor encoded by the Egr-1 gene, which plays key roles in many aspects of vertebrate embryogenesis and in adult vertebrates. The Egr-1 expression is important in the formation of the gill vascular system in flounders, which develops during the post-hatching phase and is essential for survival during the juvenile period. However, the complete details of Egr-1 expression during embryo development in olive flounder are not available. We assessed the expression patterns of Egr-1 during the early development of olive flounders by using reverse transcription polymerase chain reaction (RT-PCR) analysis. Microscopic observations showed that gill filament formation corresponded with the Egr-1 expression. Thus, we showed that Egr-1 plays a vital role in angiogenesis in the gill filaments during embryogenesis. Further, Egr-1 expression was found to be strong at 5 days after hatching (DAH), in the development of the gill vascular system, and this strong expression level was maintained throughout all the development stages. Our findings have important implications with respect to the biological role of Egr-1 and evolution of the first respiratory blood vessels in the gills of olive flounder. Further studies are required to elucidate the Egr-1-mediated stress response and to decipher the functional role of Egr-1 in developmental stages.

• Fisheries and Aquatic Sciences
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• 제20권9호
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• pp.20.1-20.8
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• 2017

The objective of this study was to examine the effect of dietary supplementation of taurine for juvenile olive flounder (Paralichthys olivaceus) at low water temperature ($16.4{\pm}0.36^{\circ}C$). Fish meal (FM)-based diet was used as the control diet. Four other experimental diets were prepared by adding taurine to FM-based diet at 0.25, 0.50, 1.00, and 1. 50% (T1, T2, T3, and T4, respectively). Each experimental diet was fed to triplicate groups of fish (initial mean body weight, 19.5 g) for 10 weeks. At the end of the feeding trial, growth performance and feed utilization, hematological parameters, non-specific immune responses, whole-body proximate composition, and liver mRNA expression of insulin-like growth factor-1 (IGF-1) were investigated. Feed conversion ratio was significantly reduced while protein efficiency ratio was significantly increased in taurine-supplemented groups. Hematocrit and hemoglobin were also significantly increased while plasma cholesterol levels were decreased in taurine-supplemented groups than those in the control group. Nitroblue-tetrazolium, myeloperoxidase and lysozyme activities, and plasma immunoglobulin level were significantly increased by taurine supplementation. These results suggest that dietary taurine supplementation is effective in improving growth performances, feed utilization, and innate immunity of olive flounder in low water temperature season.

• 한국자원식물학회지
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• 제22권5호
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• pp.394-402
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• 2009

기내배양을 이용하여 Pteris cretica 'Wilsonii'의 효율적인 대량번식법을 개발하기 위한 목적으로 근경, 엽신 및 엽병조직으로부터 식물체 재분화를 유도하였다. 그 결과, 균질화된 근경의 절편에서만 신초가 재생되었다. 식물체 재분화를 유도하는데 적합한 배지는 1%의 sucrose와 $50\;mg{\cdot}mL^{-1}$의 $NaH_2PO_4$를 첨가한 1/8MS배지였다. 근경 절편으로부터 식물체의 재생을 촉진하기 위하여 생장조절물질이 첨가된 배지에서 2달 동안 절편을 배양한 후, 생장조절물질을 첨가하지 않은 배지로 이식한 결과, $1{\mu}M$의 kinetin과 $5{\mu}M$의 NAA를 혼용첨가한 처리구에서 신초의 재생이 가장 왕성하였다. BA 첨가구에서는 분열조직의 일종인 GGB가 다량 유도되었으나, 형성된 GGB에서 신초 재생율은 낮은 것으로 나타났다. MS배지의 적정 무기물 및 비타민의 농도를 구명하는 실험을 마친 뒤, 형성된 유묘를 이용하여 기외순화 시킨 결과, 1/8MS배지에서 형성된 유묘가 생존율이 가장 높았으며, 생육 또한 왕성하였다.

• 한국양식학회지
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• 제17권3호
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• pp.221-227
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• 2004

본 연구에서는 황복, T. obscurus의 초기발달동안 자치어의 성장과 생존에 미치는 먹이 종류와 염분별 영향을 조사하였다. 먹이별 실험에서는 Artemia공급 시기인 부화 25일의 자어를 이용해 Artemia (대조구)와 5가지의 먹이 (실지렁이, 물벼룩, 바지락육질, 배합사료, 곤쟁이)를 30일간 혼합 공급하여 실험구별 성장과 생존율을 비교하였다 염분별 실험에서는 일령 15일 자어(전장 5.8$\pm$0.4 mm: Stage I), 일령 36일 치어(전장 12.0$\pm$0.2 mm: Stage II) 및 일령 70일 치어(전장 44.5$\pm$0.7mm: Stage III)를 대상으로 4개의 염분 농도구(0, 10, 20 및 30 psu)를 설정하여 성장과 생존을 비교분석하였다. 먹이실험 결과, 성장도는 배합사료, 실지렁이, 물벼룩 공급구들이 비교적 양호하게 나타났으나, 생존율은 물벼룩 공급구가 가장 높게 나타났으며, 빠른 성장을 보였던 배합사료와 실지렁이 혼합 공급구는 오히려 낮은 생존율을 나타내었다. 염분별 실험에서는 Stage I 경우 성장에 있어 염분별 뚜렷한 차이를 찾아 볼 수 없었으나, 생존율은 10∼20 psu구에서 높게 나타났다. 또한 Stage II의 경우 성장과 생존 모두 10∼20 psu에서 양호하였으며, Stage III에서는 0∼30 psu의 모든 염분 조건에서 정상적인 성장과 생존을 나타내었다.

• Journal of the Korean Wood Science and Technology
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• 제42권3호
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• pp.327-338
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• 2014

종자의 산지가 다른 루브라참나무(24년생)를 대상으로 물리 및 역학적 관계를 조사하여 생장속도와 목재의 재질과의 관계를 규명하였다. 생재함수율은 변재보다 심재가 높은 것으로 나타났고, 산지 간에 차이를 나타냈다. 비중의 경우 심재는 생장이 좋을수록 작아지는 경향을 보였고, 변재는 생장이 좋을수록 커지는 관계를 나타냈다. 전수축률은 산지간 차이를 나타냈으며, 생장이 좋을수록 수축률과 T/R율은 높아지는 것으로 나타났다. 압축영계수, 휨강도와 휨영계수 및 충격강도는 산지 간 차이를 보였으며, 생장이 좋을수록 낮아지는 경향을 보였다. 전단강도는 산지 간 차이를 보였으며, 생장이 좋을수록 커지는 경향을 보였다. 경도는 세 단면에서 산지 간 차이를 보였으며, 생장이 좋을수록 커지는 경향을 나타냈다. 5종의 산지가 다른 루브라참나무 중 Bancroft산 종자의 경우가 가장 좋은 수고생장을 보이고, 세 번째의 흉고직경을 나타내며, 압축, 휨, 경도, 전단, 충격강도 모두 우수하여 생장과 재질면을 고려했을 때 현시점에서 가장 우수한 품종으로 판단된다.