• Journal of Aquaculture
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• v.13 no.3
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• pp.197-206
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• 2000

At the Poryoung coast, the spawning season of the mullet, Chelon lauvergnii lasts from May to June. A combination of rotifer, Rotifer nauplii and synthetic feed supported significantly (P < 0.05) better survival and growth of 1-day old mullet larvae during 70-day rearing experiment than the other feeds consisting of rotifer or rotifer + Artemia nauplii. Significantly higher growth and survival were also observed, when the larvae were fed on rotifer, that were harvested from culture enriched with masimaTR, or Artemia nauplii from culture enriched with cuttlefish liver oil, At the feeding density of 97-98 individuals /200 l, the mullet larvae displayed maximum growth and survival in aquarium each with 100 larvae /200 l.

• Korean journal of applied entomology
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• v.40 no.2
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• pp.111-115
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• 2001

Orius strigicollis Poppies is an indigenous natural enemy of thrips pests in Korea To develop an efficient mass rearing system for Ο. strigicollis, effects of hatchability, egg numbers and egg harvesting time of Ο. strigicollis were measured in cylindrical cage (251 ㎤) under the conditions of photoperiod 16L : 8D, $55\pm$10% RH and $25\pm$$2^{\circ}C$. The hatchability and developmental period of eggs were 88.5% and 5.7 days, respectively. The highest emergence rate (50.8%) was achieved when the number of eggs laid was ranged from 50 to 100 per arena. The proper harvesting time of newly produced adults was 17 days postoviposition. Relationship between the number of resulting adults per female and the number of female adults per arena was Y : -10.7971n (X) +44.659 ($R^2$=0.7619). The generation time (T), the net reproductive rate ($R_{0}$ ) and the intrinsic rate of natural increase ($r_{m}$ ) were 26.5 days, 6.18 and 0.0687, respectively.

• Journal of Sericultural and Entomological Science
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• v.51 no.2
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• pp.89-94
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• 2013

The aim of the present study is to investigate food consumption, hatching periods, adult mortality, the mean number of hatchlings and ovipositional trend of Gryllus bimaculatus De Geer. The rearing and experiments were conducted in the rearing room ($28{\pm}2^{\circ}C$, $60{\pm}10%$RH). As the adult rearing density increased from 50 to 400, it did not affect the average daily food consumption of adult crickets which was $0.067{\pm}0.008$ g a day. However, the daily radish consumption decreased from 0.128 to 0.068 g per day. 95.8% of eggs hatched by the sixth day after the beginning of hatching. The average mortality of the adults gradually increased, and reached 93.9% by the 8th week. Total number of hatchlings per female was $172.2{\pm}10.6$ ($mean{\pm}SD$) in 200 females rearing cages, which was noticeably less than $248.8{\pm}17.8$ ($mean{\pm}SD$) in 100 females rearing cages. Sex ratio of the crickets given in the rearing cages did not affect both the number of hatchlings and ovipositon rate. Oviposition rate periodically fluctuated as progressed, and it reached 81.5% of the total oviposition by the $3^{rd}$ week since the beginning of ovipoisiton.

• KOREAN POULTRY JOURNAL
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• v.41 no.11
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• pp.182-185
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• 2009

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.140-145
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• 2002

The performances of a parallel current air driven type foam separator were evaluated in the pilot-scale recirculating aquaculture system. The system was stocked with Nile tilapia (Oreochromis niloticus) at an initial rearing densities of $2\%$, $5\%$ and $7\%$ of water volume of rearing tank and reared for 15, 30, 35 days, respectively. The condensated volume of effluent foam was increasing with increased rearing density. As increasing rearing density from $2\%$ to $7\%$, the protein concentration in rearing tank was increased from 16.6 g/$m^3$ to 21,9 g/$m^3$ and the removal amount of protein through foam separator as increased from 0.99 g/day to 2.5 g/day. But protein concentration ratio in the foam was decreased from 3.2 to 1.9. Changes of the removal amount and the concentration ratios of total suspended solid (TSS) and chemical oxygen demand (COD_cr.) were similar to proteins. The highest concentration ratios of TSS and COD_cr. were 10.2 and 8.4 at 2$2\%$ of rearing density.

• KOREAN POULTRY JOURNAL
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• v.56 no.7
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• pp.152-156
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• 2024

육계는 '살코기를 위해 기르는 닭'을 말한다. 우리나라도 2014년부터 육계 농장의 동물복지 인증제를 시행하고 있다. 우리 제도는 닭의 사육밀도, 먹이와 물 공급 시설, 휴식 공간 등의 기준을 정해놓았지만, 해외에서는 닭의 품종까지도 고려하고 있다. 빨리 자라는 육계는 다리에 힘이 약하거나 발바닥 피부염 등의 문제가 발생할 수 있다. 그래서 육계 동물복지를 위해 천천히 자라는 품종을 기르자는 의견도 있지만 천천히 자라는 품종은 생산비가 많이 들기 때문에 농장에서 쉽게 받아들이기 어려운 실정이다. 최근 외국의 한 연구팀이 기존의 빨리 자라는 육계 품종을 이용해 사료 급여량과 사육밀도를 조절하여 천천히 자라게 한 뒤, 닭의 복지와 행동을 살펴보았다. 사료를 적게 주고 사육밀도를 낮추면 닭이 천천히 자랐고, 깃털 상태, 활동성, 발바닥의 건강상태는 좋아졌지만, 사료 효율은 낮아지고 원하는 무게에 도달하는 데 더 오랜 시간이 걸렸다. 이 연구를 통해 닭의 복지를 위해서는 성장률과 사육밀도를 잘 조절해야 한다는 것을 알 수 있었다. 향후 육계 농장은 생산성과 동물복지를 함께 고려해야 하는데, 이번 연구 결과는 앞으로 더 나은 육계 농장이 되기 위해, 우리가 풀어야 할 문제를 엿볼 수 있었다.

• Journal of Aquaculture
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• v.15 no.3
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• pp.131-138
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• 2002

Fed on commercial flounder diet at 20, 23 and $26^{\circ}C$ in semiclosed culture system for 32 weeks, the juvenile red drum (1.2 g) showed linear increase in daily feeding rate (DFR), growth (g/fish) and specific growth rate (SGR) with increasing temperature. In the second experimental series, the young red drum (214 g), cultured at densities of 2.16, 4.24 and 6.40 kg/$m^3$ in flow-through tanks at water temperatures from 12.3 to $27.2^{\circ}C$ for 25 weeks, grew faster at the stocking density of 2.16 kg/$m^3$ than at the densities of 4.24 and 6.40 kg/$m^3$ the difference in growth observed at the stocking densities of 4.24 and 6.40 kg/$m^3$ was not significant. The DFR and SGR were also significantly higher for the density group of 2.16 kg/$m^3$. Briefly, growth of the red drum increased with increasing tested range of temperature and was also faster with decreasing stocking density. However, the total growth (g/tank) increased with increasing stocking density.

• Journal of Animal Environmental Science
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• v.17 no.sup
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• pp.7-20
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• 2011

This study was conducted to analyze the mixing ratio of raw feed materials for the methane mitigation and also to identify the minimum rearing density for improving the productivity of beef calves as eco-friendly fodder. Raw materials used in this study for the formulation of feed for methane reduction were crushed corn and alfalfa along with other 21 species. In addition, to investigate the appropriate rearing density, 12 Hanwoo calves with average weight of 150 kg was selected and experiment was conducted for four months. Methane gas emission (Bo) is about 3-4 times less in TMR 4 compared to TMR 1, 2 and 3. Feed price calculated for TMR 4 ration was also affordable. In addition, all TMRs showed a normal ruminal pH. Disappearance rate was observed to be lower in TMR 4 as compared to TMR 1, 2 and 3, but methane production decreased by 24 to 37%. The result showed improved total body weight, average daily gain and feed conversion ratio in rearing low-density ($18m^2/head$), and general treatment ($9m^2/head$) compared to overcrowding treatment ($6m^2/head$). In addition, blood components (total protein, glucose, AST, ALT and GGT factors) involved in health and disease treatments and health-related nutrition metabolism are lower in the low-density and general treatment compared to the high density treatment. Postural development (development of body size) i.e., weight, height and width significantly increased in the low and general density treatment compared to high density treatment. Especially excellent improvement was observed in low-density treatment than the general treatment. Moisture content, colonic bacteria and coccidium are higher in low and high density treatments than in the general treatment. The adequacy for beef rearing density is considered to be more desirable in an area more than $6m^2/head$. In conclusion, present study suggests that possibility of methane reduction through adjusting mixed feed ration. Also, rearing density is also an important factor in the growth and development of beef calves.

• Korean Journal of Organic Agriculture
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• v.23 no.2
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• pp.359-372
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• 2015

This study was to assess the effects of sowing mixed legume forage and applying fermented cattle manure on the productivity and feed value of whole crop wheat (WCW) as a representative of winter crops and also to estimate feeding capacity of Korean native cattle (Hanwoo) per unit area by defining optimal application levels of cattle manure for more fertile soil and manure recycling for the purpose of reduced environmental pollution and efficient production of organic forage contributable to production of organic animal products. Sowing mixed legume forage significantly (p<0.05) increased yields of dry matter (DM), crude protein (CP) and total digestible nutrients (TDN) for WCW compared to WCW alone sowing, but there were no differences between mixed sowing treatments. The yields of DM, CP and TDN were significantly (p<0.05) higher in 100~150 kg N/ha. The CP and acid detergent fiber (ADF) contents were highest in mixed sowing with hairy vetch, followed by sowing mixed forage pea and WCW alone (p<0.05). There were no differences in CP among cattle manure application levels. As nitrogen application level increased, ADF content increased (p<0.05), but TDN content decreased (p<0.05). Feeding capacity of organic Hanwoo (head/ha) weighing 450 kg of body weight with 400 g of daily gain significantly (p<0.05) increased due to mixed sowing with legume forage, and with increasing application levels of fermented cattle manure, feeding capacity significantly (p<0.05) increased. The results indicated that mixed-sowing of WCW and legume forage not only reduced nitrogen application level of fermented cattle manure by over 50 kg per ha but also increased their feed value and productivity, and feeding capacity. This would be contributable to diversity of forage resources as well as production of organic animal product by creating low cost and high quality of forage.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.421-429
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• 2016

Tenebrio molitor larvae contain large amounts of proteins, lipids and other functional materials, enabling this insect to be used as an edible food source in animal feeds and for industrialization. Although many efforts have been made to set up mass rearing systems, few studies have been conducted to establish optimal rearing conditions for the production of high quality T. molitor larvae. Herein we investigated 1) the effects of additional diets on the survival and fecundity of the insect, 2) the relationship between oviposition period and the uniformity of larval size, 3) the effects of rearing density and temperature on insect development, and 4) the storage stability of eggs and pupae at low temperatures given possible temporary production discontinuation. The addition of carrot and zucchini to the traditional wheat bran diet significantly increased the survival and fecundity rate of adult T. molitor. Of the three different oviposition sampling periods (3, 7, and 14 days) used to investigate the uniformity of the hatched larvae in each treatment, the period of 3 and 7 days provided higher uniformity than the 14 days oviposition period. Larval development was faster at $30^{\circ}C$ than at 20, 25, and $35^{\circ}C$. Interestingly, oviposition rates were highest at $20^{\circ}C$ but showed much slower larval development and lower uniformity at $30^{\circ}C$. Regarding the effect of larval rearing densities (1, 10, 20, 30, 40, and 50 larvae per 90 mm diam. dish), larval weight was significantly reduced at higher rearing densities, but larval longevity and length were not influenced by rearing density. The 30 larvae/dish is suggested to be a reasonable density to be applied to mass production systems. When kept at $4^{\circ}C$, T. molitor eggs showed a significant reduction in hatching rate; however, when stored under the same conditions, pupae emergence rates remained high until 10 weeks, suggesting that storage at low temperatures is more suitable for the pupal stage than the egg stage. Our findings suggest that an increase in T. molitor adult survival and fecundity rates and a uniformity of hatched larval development can be achieved with the following recommendations: a combination diet (including wheat bran), a 7-day oviposition period; a larvae-rearing temperature of $30^{\circ}C$, a rearing density of 30 larvae/dish, and the storage of pupal stages at low temperatures in the case of rearing discontinuation. This study serves as a strong foundation for the successful mass production of high quality T. molitor larvae.