• 한국음향학회지
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• 제37권4호
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• pp.248-255
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• 2018

세단 타입에 비해 해치백 타입의 차량은 실링구조 확보에 어려움이 있기 때문에 후석에서 느껴지는 차폐성능이 열세한 것으로 알려져 있다. 차량의 차폐감 확보를 위해 강건한 실링 시스템과 충분한 흡음/차음 성능이 요구되지만 준중형 이하 세그먼트에서는 원가, 중량의 제약으로 인해 충분한 흡차음 사양 적용에 제한을 받고있어 효율적인 흡차음 사양의 적용이 요구되고 있는 실정이다. 본 연구에서는 정량적인 측정과 비교, 분석이 가능한 파워기반 소음감소(Power Based Noise Reduction, PBNR) 기반의 차음 윈도우 평가를 통해 준중형 해치백 차량의 후석 소음원의 전달 경로를 분석하고 후석 차폐성능 확보를 위한 흡차음 대안을 제시하였다.

• 한국응용곤충학회지
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• 제39권2호
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• pp.117-122
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• 2000

Benzoylphenylurea계 살충제(BPUs)는 많은 종의 곤충에 불임을 유발하는 것으로 알려져 있다. 이전의 실험결과 집파리의 불임에 효과적인 것으로 밝혀진 4가지 BPUs의 발육단계가 다른 집파리 성충에 대한 불임효과를 실험하였다. 수컷 성충 및 우화 후 교미하기 전의 암컷(우화 1일 후)과 교미 후 난소가 충분히 발육한 상태의 암컷(우화 5일 후)을 300 ppm의 약제에 24시간 동안 접촉시킨 후 1~2일 간격으로 채란하여 부화율을 조사하였다. Flufenoxuron과 teflubenzuron에 처리된 5일 암컷이 처리 1일 후 산란한 알은 전혀 부화하지 못하였고, triflumuron과 diflubenzuron에 처리한 5일 암컷이 산란한 알의 부화율을 23%로 크게 감소하였다. Flufenoxuron에 처리된 1일 파리가 처음 산란한 알은 es지 1%의 부화율을 보였다. 따라서 본 실험에서 사용한 4가지 BPUs계 살충제는 집파리 성충의 연령에 관계없이 산란된 알의 부화를 억제할 수 있었으며, 부화한 유충의 일부는 번데기까지 자라지 못하고 사망하였다. 실험에 사용한 4약제 중에서 flufenoxuron의 부화억제 효과가 가장 우수하였으며, 약효가 5일간 지속되었다.

• 한국발생생물학회지:발생과생식
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• 제18권3호
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• pp.139-143
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• 2014

Different with other fishes, the guppies (Poecilia reticulata) is ovoviviparity, which retain their fertilized eggs within the follicle throughout gestation. The synchronously growing diplotene oocytes store nutrients in droplets and yolk, before their maturation and fertilization. The lecithotrophic strategy of development entails the provisioning of embryos with resources from the maternal yolk deposit rather than from a placenta, it allows the extracorporeal culture of guppy embryo. Studies on their early development of live bearers like the guppy including lineage tracing and genetic manipulations, have been limited. Therefore, to optimize conditions of embryo in vitro culture, explanted embryos from pregnant females were incubated in embryo medium (L-15 medium, supplemented with 5, 10, 15, 20% fetal bovine serum, respectively). We investigated whether the contents of FBS in vitro culture medium impact the development of embryos, and whether they would hatch in vitro. Our study found that in 5% of FBS of the medium, although embryos developed significantly slower in vitro than in the ovary, it was impossible to exactly quantify the developmental delay in culture, due to the obvious spread in developmental stage within each batch of eggs, and embryos can only be maintained until the early-eyed. And although in culture with 20% FBS the embryos can sustain rapid development of early stage, but cannot be cultured for the entire period of their embryonic development and ultimately died. In the medium with 10% and 15% FBS, the embryos seems well developed, even some can continue to grow after follicle ruptures until it can be fed. We also observed that embryonic in these two culture conditions were significantly different in development speed, in 15% it is faster than 10%. But 10% FBS appears to be more optimizing condition than 15% one on development process of embryos and survival rate to larvae stage.

• 한국가금학회지
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• 제27권3호
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• pp.169-179
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• 2000

An experiment was conducted to measure the effect of crude phytase supplementation on the growing performance, blood concentrations of some minerals and tibia characteristics of broiler chickens. Day-old 240 male broiler chickens (Avian) were randomly allotted to four treatments. There were six replicates per treatment, and ten chicks per replicate. Treatments consisted of two levels of crude phytase (0 and 600U/kg) made from Aspergillus ficuum and two levels of non-phytate P (0.45 and 0.35% NPP for the starter period, and 0.35 and 0.25% NPP for the grower period), making the experiment 2$\times$2 factorial. The starter period was from hatch to 21 d of age, and grower period was from 22 to 35 d of age. Feed intake and weight gain of chicks fed diet containing phytase were higher(P〈0.05) than those of chicks fed diets without phytase, however, no differences was found in feed/gain. mortality, and nutrient availabilities regarding the phytase supplementation. Chickens fed diets with low NPP and phytase excreted lower P than did birds fed diets containing normal NPP without phytase. The level of NPP and phytase did not affect N excretion. The Ca availability was increased by feeding low NPP diet. Dietary phytase increased the availabilities of P and Mg, but decreased those of Fe and Zn. There was interactions between dietary NPP level and phytase addition on mineral availability. Tibia was lighter and shorter in low NPP groups, and heavier in phytase treated groups. The tibial contents of Ca, P and Mg decreased in low NPP treated groups, but increased in phytase treated groups. The ash content of tibia of chickens fed diet with phytase was higher than that of birds fed diets without phytase. These data suggest that the crude phytase supplementation to broiler diets containing low NPP level improves growth performance and mineral availability and, reduces fecal P excretion.

• 한국가금학회지
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• 제46권4호
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• pp.287-296
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• 2019

Avian sex determination system involves the male ZZ and female ZW chromosomes. However, very few studies are reported the expression, functional role and importance of genes on the W chromosome because of its small and highly heterochromatic genomic regions. Recent studies demonstrated that the W chromosome may have critical roles in physiology, sex determination and subsequent sexual differentiation in chickens. Therefore, gene annotation, including describing the expression and function of genes in the chicken W chromosome, is needed. In this study, we have searched the W chromosome of chickens and selected a total of 36 genes to evaluated their specific expression in the testis and ovary at various developmental stages such as embryonic day 6 (E6), hatch and adult. Interestingly, out of 36 genes in chicken W chromosome, we have found seven female-specific expression at E6.5 day, indicating that they are functionally related to female chicken gonadal differentiation. In addition, we have identified the stage specific gene expression from the sex specific genes. Furthermore, we analyzed the relative location of genes in the chicken W chromosome. Collectively, these results will contribute molecular insights into the sexual determination, differentiation and female development based on the W chromosome.

• 한국어류학회지
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• 제22권3호
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• pp.195-200
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• 2010

대구 부화자어 대량방류를 위한 기초 연구로서 대용량 부화기를 이용한 대구 수정란 부화 방법을 검토하였다. 기존의 용량 15L와 시험용 42L인 부화기에 수정란을 수용한 결과 9일째 생존율이 48.3%와 50.4%로 나타나 부화기 용량차이에 따른 생존율은 유의한 차이가 없었다. 제작한 실험 부화기와 기존의 원형수조에서 수정란 생존율을 비교한 결과 40.0~71.2%로 부화기에서 높아 대구 수정란 부화에 실험 부화기가 효율적인 것으로 사료된다. 또한 42 L 부화기에 수정란 5,000 mL (약 825만 개)를 수용하여도 높은 부화율을 유지하였다. 결과적으로 대구 수정란 부화 시 대용량 부화기를 이용할 경우, 고밀도로 수용하여도 높은 수정란 생존율 유지가 가능하고 사육 공간과 인력 및 경비를 절감할 수 있을 것으로 생각된다. 또한 원형수조에 비하여 사육수 절약 (6,700 mL/min)과 수정란 그룹별 수용이 가능하다는 장점이 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권8호
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• pp.1158-1164
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• 2003

In two feeding experiments male and mixed-sex broiler chicks were offered diets based on sorghum and a wheatsorghum blend with two tiers of nutrient specifications, without and with microbial phytase (600 and 800 FTU/kg), from 7-25 and 1-42 days post-hatch, respectively. The nutrient specifications for protein, amino acids, energy density and phosphorus (P) of standard diets were reduced to formulate the modified diets on a least-cost basis. Calculated differences in nutrient specifications between standard and modified diets ranged from 14.3 to 17.1 g/kg crude protein, 0.24 to 0.40 MJ/kg apparent metabolisable energy (AME) and 1.06 to 1.20 g/kg available P. In both experiments, reduced nutrient specifications had a negative impact on growth rates and feed efficiency and phytase supplementation had a positive influence on growth performance and protein efficiency ratios (PER). Phytase addition to the less expensive, modified diets either partially or entirely compensated for reduced growth performance and, consequently, feed costs per kg of live weight gain were reduced. In Experiment 1, phytase increased (p<0.001) nitrogen-corrected AME (AMEn) from 15.39 to 15.89 MJ/kg dry matter. For nitrogen (N) retention there was an interaction (p<0.05) between diet type and phytase as the effects of phytase on N retention were more pronounced in the modified diets, with an increase from 0.512 to 0.561. These results demonstrate the positive effects of phytase on protein and energy utilisation, in addition to its established liberation of phytate-bound P and illustrate the feasibility of assigning nutrient replacement values to the feed enzyme for consideration in least-cost ration formulations. Further work is, however, required to define the most appropriate reductions in nutrient specifications in association with phytase supplementation.

• Asian-Australasian Journal of Animal Sciences
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• 제14권2호
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• pp.288-296
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• 2001

The behavior of declawed emus in a farm environment has not been described despite its importance in the husbandry and welfare of the emu. This study examined whether declawing of emus causes chronic pain resulting in permanent changes in the locomotor and general behavior of declawed yearling emus compared to emus not declawed. One group of 40 emus were declawed on the day of hatch by removing the distal phalangeal joint using a Lyon beak-trimming machine. Another group of 40 emus not declawed were the controls. Declawed emus one year of age were allocated to a paddock $250m{\times}125m$, while the control group was placed in an adjoining paddock of the same dimensions. One hour video records of individual emus from each treatment were made from 08:00 and 17:00 h over 2 periods; firstly when food and water was available and secondly during a period when food and water was not available after being withdrawn overnight. Inactive, ingestive, posture change, grooming, aggressive and locomotor behaviors were monitored from the videotape. There was no behavioral evidence to indicate loss of locomotor ability of declawed emus or to suggest declawed emus were suffering from severe chronic pain as indicated by declawed emus engaging in significantly more bouts (p<0.05) and time of searching (p<0.05). Declawed emus also engaged in less stereotype pacing (p<0.05) indicating they were under less stress and not as frustrated as control birds which engaged in more step pushing behavior (p<0.05). Modelling analysis showed that pecking behavior in birds was most closely related to foraging behavior. Birds subject to pecking attacks demonstrated higher levels of stereotype behavior presumably as a method to cope with stress. The behavioral evidence in this study would indicate that declawing does not compromise the locomotor ability of emus and has the benefit of improving the social structure in the groups by reducing stereotype behavior and aggression.

• 한국수산과학회지
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• 제53권4호
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• pp.530-537
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• 2020

This study compared the survival rates, growth, and fatty acid content of larval Pacific cod Gadus macrocephalus fed with rotifers raised on different enrichment diets. We used four commercial rotifer enrichment products (one domestic, ER1, and three imported, ER2, ER3 and ER4). Twelve 200-L tanks were used, with three replicates per treatment. Larvae were fed rotifers 3 times daily at a rate of 5 rotifers/ml/feeding from 7 to 21 days post-hatch. At the end of the feeding trial, the survival rate and total length of larvae fed ER3 were greater than those of larvae fed ER1, ER2, or ER4. ER3 had the highest proportions of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and polyunsaturated acid (PUFA). Partially reflecting this composition, larvae fed ER3 had the highest proportions of DHA and PUFA. These results show a positive effect of rotifer DHA and PUFA proportions on the survival and growth rates of Pacific cod larvae.

• 한국응용과학기술학회지
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• 제28권3호
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• pp.273-283
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• 2011

The objective of this study was to determine the feeding effect of a diet containing Cordyceps with fly pupa on the changes in blood lipid profile from broiler chickens, fatty acids and thiobarbituric acid reactive substances (TBARS) in chicken meat. A total of 360 chicks (Ross strain 308) were divided on hatch day into four treated groups with respect to a 35-day feeding regimen: T1 (control group), T2 (2.0% Cordyceps with fly pupa), T3 (3.5% Corceps with fly pupa) and T3 (5.0% Cordyceps with fly pupa). Blood triacylglyceride and total cholesterol level was significantly decreased by 5.32-10.63% and 9.23-12.62%, respectively, in groups T2, T3 and T4 when compared to T1 (p<0.05). Water holding capacity was significantly highest in T2 (p<0.05), while there were no significant differences among groups T2, T3 and T. In chicken meat, the ratio of saturated fatty acid to unsaturated fatty acid was high in the T3 and T4 groups, the ratio of n-6 to n-3 fatty acid was low in the T2, T3 and T4 groups and oleic acid (18:1n-9) was high in the T2, T3 and T4 groups, when compared to T1 (p<0.05). TBARS tended to increase according to the storage time (in days), and was significantly lower in the chicken thigh muscles with skin in groups T2, T3 and T4 as compared to T1 (p<0.05). These results suggest that a diet containing 2.0-3.5% of Cordyceps with fly pupa may decrease blood lipid and improve both the shelf-life and quality of broiler chicken meat.