• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.219-228
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• 2016

A total of 720 slow-growing Korean meat-type (Hanhyop 3) chicken were used to evaluate the effect of stocking densities and dietary protein levels on growth performance, meat quality, bone mineral composition, and serum corticosterone. Three (6.3, 9.5, and $12.6birds/m^2$) stocking densities and two dietary protein levels (19% and 18%) were factorially ($3{\times}2$) arranged for six treatments. Overall body weight gain (BWG) was highest (p<0.001) at the lowest stocking density ($6.3birds/m^2$). The feed intake (FI) of birds at the highest density ($12.6birds/m^2$) was lower than that of birds at the other densities, but resulted in better feed/gain (F/G). Among 18% protein groups, the overall FI of birds at $9.5birds/m^2$ was higher than that at the lowest density; therefore, birds at $9.5birds/m^2$ had poorer F/G than birds at the lowest density during days 61~75. Difference in F/G among densities was only significant (p<0.05) during days 61~75 but not significant (p>0.05) during days 41~60. Although there were no significant differences (p>0.05) in BWG and F/G between 19% and 18% dietary protein levels, FI of the 18% protein diet was less (p<0.05) than that of the 19% diet. Although there was no difference (p>0.05) in meat TBARS values, meat color differed (p<0.05) with stocking density and dietary protein levels. There was no effect (p>0.05) of stocking density and dietary protein levels on bone mineral composition. Serum corticosterone concentration increased (p<0.05) with increasing stock density but was not affected (p>0.05) by dietary protein levels. This study indicated that a density of $12.6birds/m^2$ is not recommended for slow-growing chickens. Between 19% and 18% dietary protein levels, 18% would be recommended for the Korean Hanhyop 3 chicken in the finishing stage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.79-88
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• 2023

A 12-week feeding trial was conducted to evaluate the effect of different stocking densities on the growth, body composition, stress, antioxidant status, and immune responses of juvenile rainbow trout Oncorhynchus mykiss. Juvenile rainbow trout (32.2±0.5 g) were randomly placed in eight experimental tanks, each containing 2,000 L of water, at stocking densities of 150, 300, 600, and 1,200 individual/m³. The trout were assigned to four treatments (2.4, 4.8, 9.7, and 19.4 kg/m³) in duplicates. Following after the feeding trial, the fish cultured in the less dense group showed significantly higher growth and survival (P<0.05). In terms of proximate composition, the whole body crude protein and lipid contents were lower in the denser group (19.4 kg/m³). Regarding the antioxidant and immune responses, the fish reared in the relatively denser group exhibited lower lysozyme, immunoglobulin M, and superoxide dismutase levels. The stress indicators, glucose and cortisol, were significantly lower in the less dense group (2.4 kg/m³), while the denser group (19.4 km/m³) exhibited higher AST and ALP levels(P<0.05). The results showed that denser stocking has a crowding stress effect and negatively impacts growth and immune responses.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.380-387
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• 2023

Stocking density is associated with Paralichthys olivaceus growth; thus, fish should be rapidly reared at high densities for commercial reasons. Studies have reported that high stocking density retards growth; however, few have investigated the malformations caused by stocking density stress. This study compared the growth and malformation rates of P. olivaceus at different densities and stress- and immune-related gene expression between malformed and normal fish. Forty days post-hatching, fish (total length, 1.49±0.02 cm) were reared at 800 (low density; LD), 1500 (medium density; MD), and 4000 (high density; HD) fish/m², and the growth rate was measured weekly. On day 30, RNA was extracted from the kidneys, and the expression of stress-, immune-, and malformation-related genes was analyzed using qRT-PCR. The malformation rate in the HD groups was approximately three times higher (62%) than that in the LD and MD groups (approximately 20%), and growth was lower regarding length and weight. The stress-related (HSP70 and GPX) and immune-related (PIR and IgM) genes showed higher mRNA expression in the HD group and malformed fish than in the LD group and normal fish. However, TLR3 showed the opposite results. In summary, high stocking density suppressed growth and increased malformation risk in P. olivaceus.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.215-221
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• 2019

This study investigated the effects of various stocking densities on the growth performance of Korean native ducks. Twelve hundred day-old ducklings were reared for 50 days in a duck house (windowless, plastic wire-floor pen). Two weeks later, 852 of these ducks (350±30 g) were selected for at least 80% uniformity per stocking treatment (six treatments, four replications/treatment, depending on a stocking density of 4~9 birds m^-2). Experimental diets were corn-soybean-based and broiler ducks were grouped based on age [0~21 days of age (CP 21%, ME 2,900 kcal/kg) and 21~50 days of age (CP 17%, ME 3,100 kcal/kg)]. Body weight (BW) did not significantly differ among different aged treatment groups (P>0.05); however, uniformity decreased with higher stocking densities (P<0.05). Feed intake and feed conversion ratio of ducks aged 42~50 days significantly decreased in the T4-6 treatments compared with the T1-3 treatments (P<0.05). In all experimental periods, BW gain was not significantly different among treatments, but feed intake decreased significantly as the stocking density increased (P<0.05), and feed conversion ratio was significantly different among six treatments with stocking density (P<0.05). In conclusion, we found that the stocking density of Korean native ducks in a plastic wire-floor pen was approximately 7 birds m^-2 in consideration of productivity and uniformity.

• The Korean Journal of Malacology
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• v.30 no.3
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• pp.219-226
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• 2014

The effects of different stocking densities on the growth and survival rate of the abalone, Haliotis discus hannai, were investigated in marine net cage for two years. Stocking density was set 15, 30, 45 and 60 percentage $(=per.)/m^2$ with share to cross-sectional area per shelter. The primary rearing period (PRP) and the secondary rearing period (SRP) were conducted by a year. One year mean water temperature of PRP and SRS showed the difference about $2^{\circ}C$. In the growth (initial mean shell length of abalone : $36.14{\pm}2.28mm$) of PRP, the absolute growth rate (ARG), daily growth rate (DGR) and specific growth rate (SGR) of the $15per./m^2$ were higher than those of density groups (P < 0.05). Survival rates of all density groups were showed no significant difference. In the growth (mean shell length of abalone : $55.26{\pm}6.93mm$) of SRP, ARG, DGR and SGR of stocking density groups showed no significant difference except for $45per./m^2$ density group. Survival rate in the low-density (15, $30per./m^2$) was more than 70%, and those of the high-density (45, $60per./m^2$) were less than 31% and 9%, respectively. These results showed that the appropriate stocking density for $15per./m^2$ was seven hundred fifty number per one net cage ($2.4{\times}2.4m$), during PRP using 3-4 cm abalone in length. Also for the secondary rearing period, the optimal stocking density (shell length 5-6 cm of abalone) consider with the economical efficiency was determined to be $30per./m^2$, resulting the productivity improved.

• Korean Journal of Poultry Science
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• v.43 no.3
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• pp.149-157
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• 2016

This study was performed to investigate the effects of the stocking density (standard stocking density (SSD, $495cm^2/bird$)) vs. high stocking density (HSD,245cm2/bird) and challenge with lipopolysaccharide (LPS, 5mg/kg BW) on the stress-related physiological indicators in chicks. There was a significant (p<0.05) decrease in body weight, but not in the weight of immune organs, between the SSD and HSD groups. The LPS group resulted in a significant (p<0.05) increase in the weights of the thymus and bursa of fabricius compared with the SSD group. Plasma biochemical components, including aspartate transaminase (AST), alanine transaminase (ALT), blood urea nitrogen, Ca, P, creatine kinase and uric acid, markedly (p<0.05) increased in the LPS birds, although no difference in these parameters was observed between the SSD and HSD birds. Furthermore, the birds challenged with LPS showed a significant (p<0.05) increase in the plasma corticosterone level, although this hormone did not differ between the SSD and HSD groups. In the mRNA expression of pro-inflammatory cytokines, hepatic $IL-1{\beta}$, IL-6 and iNOS in the LPS group significantly (p<0.05) increased compared with those in the SSD group. Thymic mRNA expression of $IL-1{\beta}$, IL-6 and IL-18 in the LPS group also significantly (p<0.05) increased compared with those in the other groups. In addition, mRNA expression of $IL-1{\beta}$ in the bursa of fabricius of the LPS group increased (p<0.05) without affecting the other cytokines. Under high stocking density, thymic $IL-1{\beta}$ was the only cytokine that was up-regulated compared with the SSD group. In conclusion, an acute stress induced by LPS challenge profoundly affected immune organ weight, blood biochemical profiles and pro-inflammatory cytokine expression, while chronic stress did not markedly affect biochemical and immunological parameters, suggesting that chicks under high stocking density could be adapted to prolonged stressors.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.83-90
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• 2003

This study was conducted to determine the effects of stocking density on performance and physiological responses of egg-type breeder layers in cages. A total of 264 Hy-Line Brown egg-type breeder layers at the age of 32 weeks were divided into 4 groups with 3 replicates of 22 birds (20 females, 2 males) per replicate and assigned to four stocking density treatments with 22 birds per cage with different sizes (980, 735, 640 and 560 $\textrm{cm}^2$/bird). The birds were fed the same experimental diet ad libitum for 12 weeks, and laying performance, egg and eggshell qualities, fertility and hatchability were determined. At the end of the experimental period, 9 birds were selected in each treatment in order to measure the scores of plumage condition. Antibody titers to Newcastle disease and infectious bronchitis were also determined. No significant differences were observed in laying performances, eggshell strength, Haugh unit, fertility and hatchability among the treatments. In birds housed 640 $\textrm{cm}^2$ per bird, eggshell thickness were significantly lower (P<0.05) than those of the other groups from 7 to 12 weeks. There was no significant difference in antibody titers to Newcastle disease. In birds housed 980 $\textrm{cm}^2$ per bird, antibody titers to infectious bronchitis were significantly (P<0.05) higher than those of the other groups. With increase in the level of stocking density, the scores of plumage condition were also significantly decreased (P<0.01). This study demonstrated that moderate increment of stocking density did not resulted in reduction in laying-performances of egg-type breeder layers. However, it seemed that the higher stocking density might give more stress to the birds from physical stimuli and thus were harmful environment causing higher mortalities compared to the lower ones.

• Korean Journal of Poultry Science
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• v.47 no.2
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• pp.83-93
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• 2020

The purpose of this study was to evaluate the effects of stocking density on feather condition, egg quality, blood parameters, and corticosterone levels of laying hens reared in conventional cages. A total of 500, 28 weeks-old Hy-Line Brown laying hens were evenly assigned to two stocking densities (750 and 500 ㎠/bird). There were 50 replicates of each treatment, each consisting of 750 ㎠/birds (n=6) or 500 ㎠/bird (n=4) birds in a cage, respectively. We observed an increase in the laying period of, the group that was assigned 500 ㎠/bird, however, this group experienced significant feather damage when compared with the group allotted 750 ㎠ bird. There was no effect of stocking densities on egg quality. These results suggest that the 500 ㎠/bird stocking density in the conventional cage can negatively affect feather condition and cause the birds to experience more stress than the group allotted 750 ㎠/bird.

• Journal of Aquaculture
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• v.16 no.4
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• pp.257-261
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• 2003

The effects of different stocking densities on the growth of juvenile abalone, Haliotis discus hannai and water quality in the recirculating system with rotating biological contactor, were assessed. The trials were conducted using total weight 32 g juveniles abalone for 60 days at stocking densities of 5, 10, 15 kg/$m^2$. The animals were fed sufficient amounts of the pellet diet of 30.4% protein during the experimental period. Daily feeding rate (DFR) and survival rate (SR) of 5 kg/$m^2$ showed 0.76% and 85.5% those were not significantly differed 10 kg/$m^2$ showing 0.75% and 96.0% (P>0.05). DFR and SR of 15 kg/$m^2$ showing 0.38% and 31.2% were significantly lower than 5 and 10 kg/m2 (P<0.05). Daily growth rate (DGR) and feed efficiency (FE) showed the highest as 0.19% and 24.2% in 5 kg/$m^2$ the lowest as 0.05% and 14.3% in 15 kg/$m^2$ (P<0.05). According to, these results was an inverse relationship between growth and stocking density. The optimum density of juvenile abalone from this experiment is 5 to 10 kg/$m^2$ in the recirculating system.