• Korean Journal of Poultry Science
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• v.36 no.1
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• pp.1-7
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• 2009

This study was performed to evaluate the effect of the level of stocking density of housing with or without window on chicken meat quality. The incidence of $1^+$ grade of whole chicken housed with window significantly influenced by stocking density. The incidence of $1^+$ grade chicken at high stocking density ($0.050\;m^2$/head), standard stocking density ($0.066\;m^2$/head), and low stocking density ($0.083\;m^2$/head) was 26, 52, and 66%, respectively. Breast muscle of chicken housed with window and with low stocking density showed higher incidence of $1^+$ grade than high stocking density. Also minor and severe PSE (pale, soft, extractive) incidence of chicken meat were showed 4% each, while the $1^+$ grade chicken was not appeared at low density. In chicken thigh, the incidence rate was not affected by stocking density. In chicken housed without window, the incidence of $1^+$ grade chicken in high, standard, and low stocking density was 18, 8, and 46%, respectively. Also, the incidence of $1^+$ grade chicken breast was 2.6 times higher than the chicken in low stocking density. However, incidence of $1^+$ grade thigh was not affected by the stocking density. These results suggest that high stocking density significantly reduced the incidence of $1^+$ grade chicken meat regardless of housing with or without window.

• Korean Journal of Poultry Science
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• v.41 no.3
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• pp.205-215
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• 2014

The aim of this study was to determine the effects of stocking density and strain on the performance and physiological adaptive responses including the plasma corticosterone content and the level of mRNA expression of pro-inflammatory cytokines and antioxidant enzymes in broiler chicks. A total of 300 birds of two strains (150 Ross strain vs. 150 Cobb strain) aged 3-d old were allotted into two stocking densities (standard stocking density,$0.046m^2/bird$ vs. high stocking density, $0.023m^2/bird$) in battery cages by $2{\times}2$ factorial designs with ten replicates until 35 d of age. There was no significant strain effect on body weight, feed intakes and feed to gain ratio and the relative organ weights. However body weight, feed intakes and relative organ weight were found to be significantly (P<0.05) affected by the effect of stocking density. Plasma corticosterone level was not affected by both stocking density and strain effects. Hepatic mRNA expression of pro-inflammatory cytokines including interleukin-$1{\beta}$ (IL-$1{\beta}$), IL-6, IL-18 and interferon-gamma (IFN-${\gamma}$) was not significantly changed by the effects of strain and stocking density. However, the mRNA expression of glutathione peroxidase (GPX) was affected by strain, showing that Ross strain decreased (P<0.05) the GPX expression. With respect to the effect of stocking density, there was a significant (P<0.05) increase in superoxide dismutase (SOD) and catalase (CAT) and GPX mRNA expression in the liver from high stocking density group. Splenic pro-inflammatory cytokine expression was not also affected by stocking density and strain, except that IL-18 mRNA significantly (P<0.05) decreased in Cobb strain under high stocking density. The mRNA expression of SOD and CAT was significantly (P<0.05) affected by the effects of stocking density and strain. In conclusion, growth performance was not affected by strain but stocking density. Although mRNA expression of major pro-inflammatory cytokines was not changed by stocking density and strain, antioxidant enzyme was significantly affected by stocking density, strain or even organ in birds under summer conditions. More detailed studies still needed to be explored to elucidate the effects of environmental conditions and genetic background on physiological responses in birds.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.27-34
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• 2002

The performances of fish culture were evaluated in the integrated recirculating aquaculture system consisting of a double drain type rearing tank ($2.5 m^3$), a sedimentation tank, a floating bead filter, a foam separator and a rotating biological contactor. A system was stocked with nile tilapia at an initial rearing densities of $5\%$ (A), $5\%$ (B) and $7\%$ (C) oyer 30 days. Feed coefficient was 1.62, 1,79 and 1.80 and average daily growth rate was $0.452\%$, 0.u5% and $0.423\%$, respectively. The level of TAN was maintained below $1 g/m^3$ for $5\%$ of initial rearing density and $2-4 g/m^3$ for $7\%$. The dissolved oxygen level ($2-4 g/m^3$) was not optimum but should not be inhibitory to fish growth. The total suspended solid was completely removed during overall experimental period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.469-475
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• 2002

The rotating biological contactor (RBC) was tested for treatment of aquacultural water in a pilot-scale recirculating aquaculture system. Performance of RBC on the treatment of nitrogen source such as total ammonia nitrogen (TAN), nitrite nitrogen and nitrate nitrogen and chemical oxygen demand (CODcr.) was evaluated. A system was stocked with nile tilapia at an initial rearing densities of $5\%$ and $7\%$ over 30 days. As increasing rearing density from $5\%$ to $7\%$, the TAN removal rates was increased from $39.4 g/m^3{\cdot}day$ to $86.0 g/m^3{\cdot}day$. But TAN removal efficiency was decreased from $24.5\%$ to $16.0\%$. The removal rate of $COD_Cr$ was higher than TAN. The RBC as an aerator was also evaluated for increasing dissolved oxygen concentration. For $5\%$ and $7\%$ of rearing density, the average aeration rate were $280 g/m^3{\cdot}day$ and $255 g/m^3{\cdot}day$, respectively.

• Korean Journal of Poultry Science
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• v.47 no.1
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• pp.1-7
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• 2020

The effect of stocking density on the growth and meat quality of native Korean chickens was investigated. A total of 364 one-day-old native Korean chickens were randomly assigned to one of 5 treatments, each of which was replicated 4 times. Five distinct stocking densities-14, 15, 16, 18, and 22 birds/㎡-were compared. The diet was fed ad libitum for 10 weeks. Results indicated that the final body weight, body weight gain, and feed intake were lower (P<0.05) for the 22 birds/㎡ stock density as compared to the other stock densities. There was no significant difference in the feed conversion ratio, proximate analysis (DM, crude protein, crude fat, and crude ash), water-holding capacity, and cooking loss among the different stock densities. These results indicate that increasing the stock density to 22 birds/㎡ elicits some negative effects on the growth performance and meat quality of Korean-native chickens.

• Korean Journal of Poultry Science
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• v.48 no.1
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• pp.13-22
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• 2021

The present experiment was conducted to evaluate the effect of stocking density on the growth performance, immune status, and meat quality of broilers. In total, 385 one-day-old Ross 308 broilers were randomly assigned to one of four distinct stocking densities: 26 birds/㎡, 22 birds/㎡, 19 birds/㎡, and 16 birds/㎡. They were fed the diet ad libitum for 5 weeks. Immunoglobulin (Ig) and corticosterone levels were evaluated, and growth performance, blood parameters, and breast meat quality were determined. It was observed that the weight gain and feed intake of growers (21~35 d) and broilers (0~35 d) were significantly reduced as the stocking density increased (P<0.05). However, the feed intake of starters (0~21 d) significantly increased as the stocking density increased (P<0.05). There were no significant differences in the biochemical profiles among the four different stock densities. Furthermore, no significant differences were observed in the stress parameters: (heterophils / lymphocytes ratio and corticosterone), IgA, and IgM; however, IgG significantly increased with stocking density (P<0.05). The pH, water holding capacity, and cooking loss of the muscle were all unaffected by the stocking density, but the shear force (tenderness) increased slightly as the density increased. The findings of this study suggest that a lower stocking density (16 birds/㎡) significantly improved the shear force of breast meat and IgG in broilers.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.99-99
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• 2003

1. 수온과 염분에 따른 부유유생의 성장과 생존율. 유생의 수온별 사육실험 결과, 3$0^{\circ}C$에서는 실험시작 6일 후 모두 폐사하였으며, 18$^{\circ}C$에서는 높은 생존율에 비하여 늦은 성장을 보였다. 24$^{\circ}C$와 27$^{\circ}C$에서 빠른 성장을 보였으나, 27$^{\circ}C$에서는 성장에 비하여 낮은 생존율을 보였다. 염분에 따른 유생의 사육시험 결과 0$\textperthousand$에서는 실험시작 10일 후 모두 폐사 하였으며, 성장은 6~9$\textperthousand$, 생존율은 3$\textperthousand$에서 가장 높게 나타났다. 2. 수용밀도에 따른 부유유생의 성장과 생존율. 유생의 수용밀도에 따른 사육실험 결과, 1$m\ell$당 1~5 개체의 저밀도에서는 성장과 생존율이 양호하였으며, 50개체/$m\ell$의 고밀도에서는 성장과 생존율이 낮았으며, 실험시작 12일째에 모두 폐사하였다. 3. 먹이생물 종류 및 공급량에 따른 부유유생의 성장과 생존율. 식물 먹이생물에 따른 유생사육 실험 결과, 혼합 공급구가 가장 빠른 성장을 보였으며, 단일 공급구에서는 I. galbana, P. lutheri, C. calcitrans 순으로 비슷한 성장을 보였으며, Chlorella sp.는 가장 늦은 성장을 보였다. 생존율 또한 혼합구가 가장 높고 I. galbana, P. lutheri, 가 비슷한 반면, Chlorella sp. 실험구가 가장 낮았다. 공급량에 따른 사육 실험에서는 먹이 공급량이 많을수록 유생의 성장은 양호하였으나, 8일 이후 50,000 cell/$m\ell$ 밀도에서 전량 폐사하였다. 실험 종료시인 12일째에는 20,000 cell/$m\ell$ 밀도에서 가장 빠른 성장과, 10,000 cell/$m\ell$ 밀도에서 높은 생존율을 보였으며, 5,000 cell/$m\ell$ 밀도에서는 성장과 생존율이 낮았다. 따라서 유생사육을 위한 기수재첩의 먹이생물의 밀도는 10,000~20,000 cell/$m\ell$가 효과적이었다.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.4
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• pp.104-112
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• 2006

Population growths of earthworm were investigated when the earthworm populations with different levels of initial densities per unit area were fed with cow dung mixed with paper mill sludge. The tested levels of earthworm densities were as follows; $1kg/m^2$, $2kg/m^2$, $3kg/m^2$, $5kg/m^2$. There were no significant differences in population growth rates 60 and 90 days after feed supply among the tested densities of earthworm. Therefore, it was suggested that initial densities of earthworm populations per unit area higher than $3kg/m^2$ should not be favorable because of the cost for purchasing earthworm. Vermicomposting rates of earthworm on feed were also investigated when different amounts of feed were supplied repeatedly to unit area of nursery bed with $5kg/m^2$ of initial densities earthworm populations. The tested amounts of feed at each supplying time were as follows; $16kg/m^2$, $24kg/m^2$, $32kg/m^2$, $40kg/m^2$. The more the amount of feed at each supplying time, the higher vermicomposting rate and population growth rate. Therefore, it should be more favorable for earthworm breeders to supply more than $40kg/m^2$ of feed at each supplying time, because it would reduce time and labor cost.

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.178-178
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• 2005

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.4
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• pp.93-99
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• 2007

Vertical distribution of tiger worm(Eisenia fetida) population in the earthworm rearing bed was investigated with feeding paper mill sludge. More than 50% of larva and adult population of Eisenia fetida lived within the depth of 5 cm from the surface of rearing bed. And more than 96% of the population of larva, adult and cocoon lived within the depth of 20 cm. Percental vertical distribution of Eisenia fetida population in the rearing bed was not much influenced by the changes in the height of rearing bed or density of earthworm population.