• Parasites, Hosts and Diseases
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• v.30 no.3
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• pp.169-176
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• 1992

In order to compare the intraspecific variation in host-parasite relationship of Clonorchis sinensis, six strains of inbred mice, ICR, DDY, GPC, BALB/c, nude and DS, were infected orally with 20 metacercariae of C. sinensis. The biologic incubation period of C. sinensis was the shortest in DDY mice, 21.2 days in average, followed by GPC 21.4, BALB/c and DS 23.2, ICR and nude 23.4 days, respectively. The fertile period of the cuke was also the longest in the DDY strain, 164 days on average, followed by GPC 132, BALB/c 97, nude 37, DS 32 and ICR 28 days. The egg-laying capacity of the cuke in DDY and GPC was relatively high and stable compared with the other four strains of mice. It was found that there are intraspecific variations in biologic incubation period, fertile period, and fecundity of C. sinensis. The DDY mouse is likely to be the most suitable experimental animal among the six strains of the mice tested. Key words: Mouse strain, Clonorchis sinensis, egg-laying capacity.

• Korean Journal of Poultry Science
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• v.14 no.2
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• pp.97-102
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• 1987

The respiratory experiment was made on laying hen fed acclimented to three temperatures of 10, 20, and 30$^{\circ}C$. 1. The FHP of laying hen decreased with increasing room temperature. 2. The feed intake and heat production(HP) all decreased with increasing temperature. However, the highest energy retention was found with optimum temperature (20$^{\circ}C$). 3, The MEm's were 128,110, and 110kcalkg 0.75 for the 10, 20, and 30$^{\circ}C$ of room temperature. The NAME's were 64,78, and 69 percent for the respective room temperature. The results indicated that the highest NAME was obtained with optimum temperature(20$^{\circ}C$). 4. Although there was no significant difference in the nitrogen retention(NR) at different temperatures, the NR was maximum at the optimum temperature(20$^{\circ}C$). 5. The experimental results suggest that in the Bone of thermal neutrality under cooler and hotter conditions heat loss is more dependent on the environmental temperature.

• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.217-223
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• 2018

The study on the spawning ecology of Sarcocheilichthys variegatus wakiyae at Jicheon stream, Korea was investigated from March 2016 to February, 2017. The sex ratio of male to female was 1 : 0.97 and there was no significant difference. The spawning season was from the end of April to the mid-July, and the peak of spawning period was from the beginning of May to the end of June. The average water temperature at this time was $18^{\circ}C$. According to frequency analysis of total length, it is presumed that the group with a total length of less than 51~70 mm was one year old, the 71~100 mm was two years old, and the group over 101 mm was three years old. They sexually matured when they were over two years. The average number of eggs in the ovaries was estimated as $428{\pm}194per$ matured female. The mature eggs were yellowish, oval, and had a mean diameter of $2.38{\pm}0.25mm$ and a short diameter of $1.98{\pm}0.20mm$.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.148-155
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• 2024

This study investigated the ecological characteristics of Odontobutis platycephala at Jaho stream from January to December 2022. The riverbed structure of the species' habitat was rich in cobble and pebble. The water was deep, ranging from 22 to 153 cm, with an average of 64 cm, and the stream velocity was rapid at 0.89 (0.42-1.46) m/sec. The ratio of females to males was 1:1.02, and the total length of collected individuals ranged from 38 to 156 mm. The age according to the total length frequency distribution as of May indicated that the group with a total length of 38-69 mm was one year old, the group with 60-99 mm was two years old, the group with 100-139 mm was three years old, and the group 140-156 mm was four years or older. As a secondary gender characteristic, the genital papilla was cylindrical in females and cone-shaped with a pointed tip in males. Some females with a length ranging from 60 to 69 mm and all females 70 mm or longer were sexually mature. Some males with a length ranging from 70 to 79 mm and all males 80 mm or longer were sexually mature. The spawning season was from May to July, and the water temperature was between 17 ℃ and 28 ℃ during that period. The prosperous spawning season was June (24 ℃). The average number of eggs in the ovaries was 988 (284-2,722) per mature female, and the mature eggs were yellowish and spherical with a mean diameter of 1.46 (1.19-1.71) mm. The correlation between total length and body weight is BW=0.00000006TL^3.12 with the constant a as 0.00000006 and the parameter b as 3.12. The mean condition factor (K) was 1.44 (0.96-2.26), and the slope was negative at -0.0007

• Development and Reproduction
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• v.9 no.2
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• pp.95-103
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• 2005

Reproductive cycle, gonadosomatic index(GSI), egg diameter composition, first sexual maturity, sexually matured length(50% of first sexual maturity), and sex ratio of Amusium japonicum japonicum, were investigated by histological observations and morphometric data. Samples were collected monthly from the subtidal zone of Sogwipo, Jejudo, Korea, for two years. The sun and moon scallop Amusium japonicum japonicum is dioecious. Monthly variation in the GSI showed similar patterns with the reproductive cycle. Ripe oocytes were about $70{\sim}90\;{\mu}m$ in diameter and had thick egg membranes. The spawning period was from November to January, and the main spawning occurred between November and December when the seawater temperature was relatively low. From monthly changes in egg diameter composition, the spawning period was once a year, although the number of spawning frequencies is assumed to occur more than twice during the spawning season. The reproductive cycle of this species could be divided into five successive stages: early active stage(April to June), late active stage(June to September), ripe stage(October to November), spawning stage(November to January), and spent/resting stage(February to April). First sexual maturities in female and male scallops ranging from 85.1 to 90.0mm in shell length were over 50% and they were 100% for scallops over 90.0mm in shell length. In this population, sexually matured shell lengths(50% of rate of group maturity) in females and males were 86.96 and 86.59mm, respectively. The female to male sex ratio among individuals over 85.1mm in shell length was not significantly different from 1:1($X^2=0.18$, p>0.05). No evidence of hermaphrodite was found in histological sections of any scallop examined.

• Korean Journal of Poultry Science
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• v.36 no.2
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• pp.149-155
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• 2009

The present study was conducted to compare the carcass yields and meat characteristics of three types of commercial male chicks White mini broilers, Ross broilers and Hy-Line brown chicks under the identical feeding condition. One-hundred 1-d chicks of each type were randomly placed into four pens per group (25 chicks per pen) and fed corn-soybean meal based commercial diets for 35d, 18d or 49d, respectively. At the end of the feeding trial, the birds were sacrificed and subjected to carcass measurements. The dressing percentages of White mini broilers and Ross broilers were significantly higher (P<0.05) than that of Hy-Line brown cockerels. The rate of breast meat of Hy-Line brown cockerels was significantly lower (P<0.05) than those of White mini broilers and Ross broilers. However, Hy-Line brown cockerels showed higher (P<0.05) leg meats than the others. There were no significant differences in serum total cholesterol and the activities of glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase among the groups. The breast meats of White mini broilers presented highest lightness value. The yellowness of breast and redness of leg meats of White mini broilers and Ross broilers were significantly higher (P<0.05) than those of Hy-Line brown cockerels. There were no significant differences in the SOD-like activity and change of pH in edible meats among the groups. The meat color in White mini broilers was significantly higher than that of Hy-Line brown cockerels. No significant differences were observed in term of flavor, tenderness and overall acceptability. In conclusion, the physico-chemical properties and sensory characteristics of edible meats were not greatly affected by genotype if they were similar body weights and kept under the identical feeding condition. But the Hy-Line brown cockerels were less desirable as a meat-type strain due to lower carcass yields and inferior growth and feed conversion ratio.

• KOREAN POULTRY JOURNAL
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• v.4 no.10 s.36
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• pp.34-46
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• 1972

1. 육추율 육성율 성계생존율 육추율 99.7$\%$는 1회 98.5$\%$, 2회 99.2$\%$, 3회 99.8$\%$, 4회 98.3$\%$ 5회 98.7$\%$와 근사하다. 육성율 평균 87.1$\%$는 1회 97.5$\%$, 2회 97.2$\%$, 3회 96.6$\%$, 4회 97.9$\%$에 비하여 10$\%$정도 낮으며 5회 89.7$\%$보다도 2.6$\%$ 낮은데 이는 근년 많이 발생하는 마렉병 및 백혈병이 주원인이며,(7회 검정계 부터 마렉병 예방접종)현 김포검정사 신축이 장마로 인하여 지연되므로서 더욱 임시육추사에서의 육성기간에 스트레스를 받았기 때문이며 성계생존율은 평균 75.3$\%$이며, 1회 80.3$\%$, 2회 84.8$\%$, 3회 71.8$\%$, 4회 87.3$\%$, 5회 71.4$\%$ 이었다. 이를 폐사원인별로 보면 세균성 질환으로 인한 폐사가 전체폐사수의 8.9$\%$ 병독(마렉병 및 백혈병)이 61.5$\%$원충 0.7$\%$ 대사장애 9.2$\%$ 생식기장애 3.4$\%$ 내장파열(간파열 탈항등) 5.7$\%$ 곰팡이 1.1$\%$ 기타(복막염 장염등) 9.5$\%$로 마렉병 및 백혈병이 주인이며 이를 검정각회별로 보면 1.2회 32.3$\%$, 3회 43.3$\%$, 4회 41.3$\%$, 5회 56.2$\%$, 6회 61.5$\%$로 매년 증가하고 있다. 2. 성성숙일령 전체평균 155.9일로 가장 빠른 구는 4구의 144일이고 가장 늦은 구는 23구의 166일이며 1일 189.2일, 2회 181.2일 보다 30일 정도 빨라진 것은 1.2회 검정은 산란율 50$\%$ 연2일 산란한 전일로 계산하였으며 3회 검정부터는 산란율 50$\%$에 달한 일령으로 계산하였기 때문이다. 3. 산란율 산란지수 산란율 평균 64.6$\%$이고 최상위구는 77.1$\%$, 최하위구는 52.8$\%$이며 유색품종 평균산란율은 58.4$\%$ 백색품종은 66.6$\%$이며 성성숙일령이 빨라짐에 따라 전체산란율은 약간 떨어지고 있다. 산란지수-평균은 189.7개로 200개 이상 산란한 상위군이 모두 성계생존율이 높은 구임을 알 수 있다. 4. 사료요구율 전체평균 2.8로 1회 3.54, 2회 3.1., 3회 3.98 4회 2.87, 5회 2.83으로 점차 개선되어 가고 있으며 유색품종의 사료요구율 평균은 3.3이었다. 5. 난평균중량 평균 58.4g로 최상위구는 60.8g, 최하위구는 56.6g 이며 국산계의 평균난중은 57.9g 외국제 평균난중 58.6g이었다. 6. 체중 평균체중은 300일령 2,117.g, 500일령 2,207이며 유색품종은 300일령 2.6160g, 500일령 2.656.7g이었다. 7. 사료 섭취량 사료섭취량 평균은 1일수당 육추기 33.6g, 육성기 68.5g, 산란기 109.9g이었다. 8 경제성 총수입은 2,539,799 으로 전체수입의 85.3$\%$가 계란수입이고, 폐계 수입은 14.7$\%$이다. 지출은 총계 1,854.517원으로 전체 지출의 92.5$\%$가 사료비, 7.5$\%$가 초생추대이었다. 9. 후기 마렉병 백신이 71년 중반기부터 수입되므로써 마렉병 예방접종을 하지 못하므로서 전체 폐사 수의 61.5$\%$를 차지하는 많은 피해를 보았다.

• Korean Journal of Poultry Science
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• v.28 no.3
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• pp.275-281
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• 2001

The objective of this study was to investigate the effect of chitosan and green tea supplementation on laying performance and cholesterol concentrations of serum and egg yolk in laying hens. Total 360 laying hens were divided into four groups for feeding trials with three replication : control, T1 (0.15% chitosan), T2(0.15% green tea) and T3 (0.15% chitosan + 0.15% green tea) group. Feed intake was lower in control group (830g/week) than other treatment groups, but T2 of treatment group shows a tendency to decrease. The egg production and egg weight was significantly higher in T2 and T3 group than control. The cholesterol concentrations of serum with chitosan or green tea supplementation were significantly decreased after 8 week than starting trial, and especially those of T2 was lower than other treatment groups. The cholesterol concentrations of egg yolk were no effect of supplement with chitosan and green tea.

• Korean Journal of Poultry Science
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• v.32 no.2
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• pp.101-106
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• 2005

This study was designed to estimate effect of wood vinegar on meat quality in old Layer which was low production and low economic value. The old layer chickens were used to resource for income increase of layer farm and protein supply. Two hundred forty Isa Brown chickens were assigned with control(Broiler feed), Treatment 1 (Broiler feed with addition of domestic wood vinegar $0.8\%$) and Treatment 2(Broiler feed with addition of foreign wood vinegar $0.4\%$). Feed intake of control group was lower 3g than other treatments. This is the reason of result that what organic acid in wood vinegar of treatment groups affect to feed digestibility, The different of chicken production was depended on ingredient and included value of wood vinegar in domestic and foreign. Foreign wood vinegar have organic acids which that functionally act sexual Pheromone so that promote endocrine matter. This is reason that old Layer chicken increase to egg production rate. Treatment 2 group effect to thigh meat rather than breast meat and improve to value of crude fat and meat color. The Meat quality and sensory test of thigh meat of foreign wood vinegar was better appraise rather than that of domestic wood vinegar. Because foreign wood vinegar make to fine of meat tissue and to decline cooking loss and also to increase juiciness and tenderness on sensory test.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.73-81
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• 2003

This experiment was conducted to investigate the effects of dietary energy and protein levels on the growth rate of egg breeder pullets. A total of 360 Hy-Line Brown pullets aged 2 to 6 weeks (Phase I) were fed 5 rations differing in dietary protein (17, 19 and 20%) and energy (2,800, 2,950 and 3,050 kcal/kg, TMEn) leveIs for a period of 5 weeks and those aged 6 to 10 weeks (Phase II) were fed 5 rations differing in dietary protein (15, 16 and 17%) and energy (2,800, 2,900 and 3,000 kcal/kg, TMEn) levels in order to evaluate the optimum dietary energy and protein leveIs for egg breeder pullets reared in cages. Their body weight gains were significantly influenced by the dietary protein levels (P<0.05). The dietary energy levels did not greatly affect the growth performances throughout the experimental period. The low energy and protein regimen based on NRC requirement (control) was found to produce smaller pullets and lower tibia bone measurements as compared to the higher regimen groups. With the increase in dietary energy and protein levels, tibial bone strength and ash content also gradually increased (P<0.05). There were no significant differences in the flock uniformity among the treatments. These results indicate that increases in dietary energy and protein levels above the NRC requirements appeared to be more effective in obtaining the optimal growth and bone developments of egg breeder pullets reared in cage.