• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.89-98
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• 2022

This study compared the production and physiological characteristics of male and female Korean native commercial chickens. We investigated the growth performance, vitality, and stress response of 479 male and 608 female chickens from 1 d to 12 weeks of age. The body weight, feed consumption and feed conversion ratio were measured as growth performance. The survival rate, amount of telomeric DNA, DNA damage rate, heterophil-lymphocyte ratio (H/L ratio), and heat shock protein (HSP)-70, HSP-90α, and HSP-90β gene expression levels were analyzed as indicators of vitality and stress response. Body weight was significantly higher in male chickens than in female chickens after 2 weeks of age (P<0.01). Feed intake was higher in male chickens than in female chickens, whereas the feed conversion ratio showed the opposite trend. The survival rate was significantly higher in female chickens than in male chickens (82.8% vs. 73.8%, P<0.05). Stress response analysis revealed no differences between male and female chickens in terms of telomeric DNA content, DNA damage rate, H/L ratio, and HSP gene expression levels. Taken together, it was concluded that there was a significant difference in the growth performance and survival rate between male and female Korean native commercial chickens, whereas there was no difference in the degree of stress response between them. Therefore, in terms of the productivity of Korean native commercial chickens, it is judged that separate-sex rearing is much more advantageous than mixed rearing, regardless of the physiological characteristics of males and females.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.41-47
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• 2006

A study was conducted to investigate the effect of supplementing earthworm meal(EWM) on the egg quality and performance of laying hens. A total of 360 laying hens at 55 weeks of age were fed the experimental diets containing 0(Control), 0.3 and 0.6% of EWM for 5 weeks. Eggs were collected and weighed in every day and egg production and feed conversion were weekly recorded. However egg quality were measured fer last week of experimental period. When fed both 0.3 and 0.6% of EWM, egg production and daily egg mass tended to increase but were not different between those treatments. Feed intake and feed conversion ratio of laying hens were not different among three groups. Egg shell thickness, breaking strength, color and egg yolk color were tend to improve in both 0.3 and 0.6% of EWM compared to those of control. The haugh units(HUs) showed no difference among each treatments at 14 after laying egg, but increased in EWM treatments compared to control for storage period. As, Cd, Cr, Hg and Pb detected 4.41, 1.23, 1.18, 0.00 and 3.39ppm in EWM, respectively, but which were not detected in control. It assumed that supplementing 0.3% of earthworm meal in the 55 weeks old laying hens diet, improved the laying performance and egg quality.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.1-5
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• 2016

For obtain fermentable sugar, we conducted acid hydrolysis with lignocellulosic biomass without enzyme. The lignocellulosic biomass used pinus rigida and Palm residues (EFB; empty fruit bunches). In the acid hydrolysis, we consider the hydrolysis condition to reduce a denatured sugar. So this study was conducted 2-step acid hydrolysis. First-step hydrolysis used high concentration (72 wt%) sulfuric acid at $80^{\circ}C$. At the condition, we obtained 11.49 wt%, 32 wt% glucose conversion for pinus rigida and EFB. After the step, the liquor was dilute until 9~15 wt% acid concentration and conducted second hydrolysis at $50{\sim}120^{\circ}C$. In the second hydrolysis, we obtained maximum glucose conversion (pinus rigida 86.8 wt% (39 g/L) and EFB 95.3 wt% (32.4 g/L)) at 9 wt% acid concentration and $120^{\circ}C$ for 80 min. All samples through the process are analyzed on the basis of mass balance.

• Korean Journal of Poultry Science
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• v.14 no.1
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• pp.55-61
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• 1987

Four treatments were conducted to determine the effects of lighting regimes on the body weight gain and feed conversion of broiler chicks during 7 weeks: 1) 24 hours consistant lighting regime, 2) intermittent lighting regime of 1 hour lighting and 3 hours dark, 3) 20 hours lighting and 4 hours dark regime, 4) natural lighting regime. Each treatment was composed of three replications and 180 broiler male chicks were used in this experiment (45 chicks for each treatment,15 chicks for each replication). The results of this experiment were summarized as follows; 1. The body weight gains of 1 hour lighting＋3 hours dark regime were heavier than those of any other treatments during whole period, but no significant differences were found. In 1-4 weeks, the body weight gains of 1 hour lighting＋3 hours dark regime and 20 hours lighting＋4 hours dark regime were much heavier than those of natural lighting regime and 24 hours consistant lighting regime, but in 5-7 weeks, no differences were found among the 4 treatments. 2. The feed conversions of 1 hour lighting＋3 hours dark regime were improved more than those of any other treatments during whole period, but no significant differences were found. In 1-4 weeks, the feed conversions of 1 hour lighting＋3 hours dark regime and 20 hours lighting＋4 hours dark regime were much more improved than those of natural lighting regime and 24 hours consistant lightine regime, but in 5-7 weeks, no differences were found among the 4 treatments. 3. These results indicated that the intermittent lighting regimes such as 1 hour lighting＋3 hours dark and 20 hours lighting＋4 hours dark are more efficient on the body weight gain and feed conversion of broiler chicks than natural lighting regime and 24 hours consistant lighting regime.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.1
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• pp.45-52
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• 2019

This experiment was carried out to study the change of productivity and feed value in different types of hilly pasture. The pasture utilized in the experiment was placed on the experimental farm of Pyeongchang Campus of Seoul National University. Forage production type(FP; Orchardgrass 18 + Tall Fescue 12 + Timothy 5 + White clover 5 kg/ha) and Public farm type(PF: Orchardgrass 12 + Tall Fescue 18 + Timothy 5 + White clover 5 kg/ha) pasture were established in September 3, 2014 and utilized (cutting or grazing) four times every year. Growth characteristics, yield and forage quality were investigated for two years. Plant height of grasses was the highest in the $1^{st}$ cutting and legumes was in the $2^{nd}$ cutting. Dry matter (DM) content was highest at every the $1^{st}$ cut grasses significantly lower at the $2^{nd}$ harvest (p<0.05). However, there was no significant difference in the $2^{nd}$, $3^{rd}$ and $4^{th}$ harvest in 2016. In the botanical composition change, the portion of legume was gradually increased after pasture establishment and the ratio of weed and bare land was higher at $2^{nd}$ and $3^{rd}$ cutting, but it was decreased at $4^{th}$ harvest. There was no significant difference in 2016 of fresh yield between two farm types (p>0.05). The yield of dry matter showed similar trend of fresh yield and forage production type was higher than that of public farm type (p<0.05). The forage intake by livestock was 1,452 kg/ha in 2015 and 1,743 kg/ha in 2016. Pasture utilization ratio of public farm type pasture was highest in the $3^{rd}$ grazing time. Forage quality of pasture in relation to management type had not significant difference, but there was difference in harvest times. Crude protein (CP) was the lowest in the $1^{st}$ harvest and total digestible nutrient (TDN) was highest in the $1^{st}$ harvest and lowest in the $4^{th}$ harvest. Based on the above results, it is found that the establishment of pasture suitable for farm's situation is important for set up of Korean model of hilly pasture. Although the forage production type is superior on forage productivity, it is recommended that the results will be provided as basic data for management of public farm type in the future.

• Journal of Embryo Transfer
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• v.16 no.3
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• pp.193-201
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• 2001

This study was designed to examine the factors affecting in fertilization and development of embryos in vitro, and to examine whether zone drilling by laser irradiation can improve the hatching rate of IVF embryos from DNA marker-proved Hanwoo. DNA markers related to marbling score were identified using DNA fingerprinting with Ml3 probe and restriction enzyme Hae III. Oocytes were aspirated from immature ovarian follicles using a combined method of rectal ovarian-palpation and transvaginal ultrasound-guidance(6.5MHz) under local anesthesia. The aspirated oocytes were washed twice with fresh D-PBS containing 5% FBS and were rewashed 4 to 5 times with TCM-199 containing 5% FBS. A morphological grade of I to IV was assigned to each oocyte. Data were analyzed using the GLM procedure of SAS. Sperm separation methods did not have any significant effect on cleavage or developmental abilities of IVF embryos. Significantly(P<0.05) higher cleavage rate was observed in embryos from GI(60.0%, 3/5), GII(69.2%, 18/26) and GIII(62.1%, 59/95) compared to embryos from GIV oocytes(36.2%, 25/69). And the developmental rate to blastocyst stage was higher(P<0.05) in embryos from GI(33.3%, 1/3) and GII oocytes(38.9%, 7/18) than those from GIII(16.9%,10/59) and GIV oocytes(4.0%, 1/25). There was no significant difference in development of IVF embryos to blastocyst by media for in vitro culture. Proportion of hatched blastocyst was significantly(P<0.05) higher in embryos received zona drilling by laser than those of non-drilled.

• Korean Journal of Agricultural Science
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• v.39 no.3
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• pp.335-340
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• 2012

During the manufacturing process of chestnut, 50% of biomass is produced as chestnut shell (CS) or chestnut hull (CH), a forestry by-product. Due to its high fiber content and economic benefit, there is a possibility of using chestnut hull as a supplement for a ruminant diet. Few studies, however, have been conducted on evaluating nutritive value of chestnut hull for ruminant animals. The objective of this study were thus to analyze chemical composition of CS, a by-product after the first processing of chestnut, and CH, a by-product after the second processing, and access in vitro rumen fermentation characteristics of them. For the in vitro fermentation using strained rumen fluid obtained from a fistulated Hanwoo steer, commercial total mixed ration (TMR) for dairy goat was used as a basal diet and was replaced with different proportions of chestnut shell and hull. A total number of 13 treatments were carried out in this study: 100% TMR, 100% CS, 100% CH, a mix with 50% CS and 50% of CH (MIX), TMR replaced with 5%, 10%, or 15% of CS, CH, or MIX, respectively. For each treatment, in vitro dry matter digestibility (IVDMD) and pH after 48 hours of rumen fermentation were measured. Gas production at 6, 12, 24, 48 hours of incubation was also analyzed. Compared to CH, CS contains higher level of fiber (NDF, ADF, lignin) and consequently has a lower amount of non-fiber carbohydrate, but no difference was observed in the other nutrients (i.e. crude protein, crude fat, and ash). IVDMD was significantly (p<0.05) the highest in 100% CH (71.97%) and the lowest in 100% CS (42.80%). Addition of CH by replacing TMR did not affect IVDMD, while an increase in the proportion of CS tended to decrease IVDMD. The total gas production after 48 hours of incubation and the rate of gas production were also the highest in 100% CH and the lowest in 100% CS (P<0.05). Likewise, the pH after 48 hours of fermentation was significantly (p<0.05) the lowest in 100% CH (6.33) and the highest in 100% CS (6.50), and no significant difference in gas production was observed when TMR was replaced with CS or CH up to 15% (P>0.05). In conclusion, CH may successfully be used for a supplement in a ruminant diet. The nutritive value of CS is relative low, but can replace, if not 100%, low quality forage. This study provides valuable information about the nutritive value of CS and CH. An in vivo trials, however, is needed for conclusively accessing the nutritive value of CS and CH.

• Journal of Biosystems Engineering
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• v.4 no.1
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• pp.35-47
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• 1979

수자원과 에너지는 식량 생산에 직접 간접으로 큰 영향을 미치고 있으며 또한 1973년 에너지 위기 이후 농업에 사용된 에너지가 효율적으로 사용되었는가에 대한 연구는 농공학자들의 큰 관심이 되어왔다. 본 연구는 필리핀의 수작농업에 있어서 경운정지시 관개에 따른 토양경도의 변화와 , 토양경도와 연료소모율과의 관계를 구명하고, 에너지와 관개수의 효율적인 이용을 연구하고저 건기와 우기에 각각 수행되었으며 그의 결과를 요약하면 다음과 같다. 가. 건기 1) 관개시작후 1-2일간 토양의 수분함량이 증가함에 다라 토양의 경도는 급격히 감소하였으며, 관개 3일째는 온난한 감소를 ,그리고 4일째부터는 거의 변화가 없었다. 2) 토양의 경도에 따라 경운작업시 연료감소율, 기계의 작업성능에 큰 차가 있었으며 , 관개 3일후 토양의 수분함량과 토양의 경도가 안정됨에 따라 각 처리간의 연료의 소모율과 기계의 작업성능도 비슷하였다. 3) IRRI 5 Hp 경운기는 관개수로 인해 경도가 낮아진 토양에서도 이동성 문제가 없을 만큼 충분히 경량이었다. 4) 관개수의 양의 따라 처리별로 경운전 토양의 전단력에 큰 차가 있었으나 , 경운정지작업후의 토양전단력은 전처리에 있어서 거의 비슷하였다. 이는 경운정지작업시 처리간의 연료소모율, 기계의 작업성능의 차로 설명될 수 있다. 5) 경운정지시의 토양상태는 식물의 생육, 잡초의 발생율에 거의 영향을 미치지 않았다. 6) 본 실험은 한가지 토양형식에 대해 수행되었으며 앞으로 여러 토양형식에 대해 이와 같은실험을 수행하여 토양형식에 따른 수분함량, 토양경도, 에너지 소모율들의 관계를 구명하여 관개수의 효율적인 이용이 가능하리라 사료된다. 나. 우기 1) 경운작업전에 이미 토양이 수분으로 포함되어 있는 상태이었으므로, 추가의 관개수가 토양의 경도, 기계의 작업성능, 연료소모율에 영향을 미치지 않았다. 2) 경운정지기간이 가장 짧았던 처리구(3일) 에 있어서 경운정지후 토양전단력이 다른 3 처리에 비해 크게 나타났다. 식물의 생육 또한 타처리에 비해 저조했으며 잡초발생율도 높았다. 3) 경운정지기간이 가장 짧았던 처리구(3일)을 제외한 3처리 간에는 연료소모율, 식물생육, 잡초발생율등이 거의 비슷하였으며, 우기에는 위의 3 처리 중 11 간의 경운정지기간이 가장 효율적인 것으로 나타났다.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.273-277
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• 2011

Fusarium oxysporum f. sp. fragariae (Fof), the causal agent of crown and root rot in strawberry, is the most serious soilborne disease of nursery plants in Korea. The possibility of infection by Fof through runner propagation from infected mother plants of strawberry cv. 'Kumhyang' was assessed in stolons and daughter plants hanging from raised beds. The number of daughter plants from an infected mother plant in plastic house and photosynthetic photon flux (PPF) system, 280 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ was 2.7 and 3.8 plants after 58 days, respectively. However, healthy mother plants produced 6.5 and 8.4 daughter plants, respectively. The pathogen was detected in the uppermost portion of the stolon after 58 days, but was not detected further down the stolon. After 90 days, it was detected in all portions of the stolon between mother and $1^{st}$ daughter plant and in 60% of all $1^{st}$ daughter plants. The pathogen was not detected in the corresponding portions of the non-infected controls. These results show that infected mother plants can transmit Fof to their daughter plants without passing through the soil and $1^{st}$ daughter was used as mother plant in PPF system for propagating healthy plants.

• Korean Journal of Poultry Science
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• v.41 no.2
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• pp.135-142
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• 2014

This study was conducted to evaluate dietary effects of Marigold extract on laying performance, egg quality, oxidative stability of egg yolk and lutein transfer into chicken eggs. A total of one-hundred eighty nine 55-wk-old Hy-Line Brown layers were divided into seven groups and fed control diet or each experimental diet containing 0.1, 0.3, 0.5, 1.0, 1.5 or 2.0% Marigold extract. Egg production, egg weight and daily egg mass were not affected by dietary treatments. The yolk colors in groups fed diets containing Marigold extract were significantly higher than that of control. The Haugh unit were tended to be improved by feeding of diets containing Marigold extract although there were no significant difference in egg shell strength and thickness. The MDA (malondialdehyde) contents in groups fed diets containing Marigold extract above 0.5% were significantly reduced than that of control. After 14d of storage, the Haugh unit values in groups feed diets containing 0.3 and 1.0% Marigold extract were significantly higher than that of control (p<0.05). The concentration of lutein in egg yolk increased by feeding of Marigold extract. When 2% Marigold extract was supplemented to the diet, lutein content of egg was increased as much as 1.71 mg/60 g. These results indicated that the use of Marigold extract in layer diets was effective in egg quality and for the production of lutein fortified eggs.