• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.914-922
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• 1999

An experiment was conducted to determine the effects of dietary energy and protein on performance and carcass composition of broilers under heat stress during the growing period (3-6 weeks). A factorial arrangement of three levels of energy (3.0, 3.2 and 3.4 kcal/g), three levels of protein (18, 20 and 22%), an two rearing temperatures were used in this study. Groups of birds were kept under moderate temperature ($24{\pm}1^{\circ}C/24h$) or hot cycling temperature ($26-34^{\circ}C/6h$, $34{\pm}1^{\circ}C/12h$, and $34-26^{\circ}C/6h$). Body weight (BW), weight gain (WG), feed intake (FI), feed conversion (feed : gain) (FC), carcass weight (CW), carcass yield (YP), breast meat (BM), abdominal fat (AF), drumsticks (DS), and thighs (TH) percentages were determined at the end of the experiment. Hot cycling temperature significantly (p<0.05) decreased BW, WG, FI, CW, and BM, increased FC, YP, DS, and TH but did not affect AF. High energy significantly (p<0.05) increased BW, WG, CW, YP, AF, and TH, decreased FI and FC but did not affect BM or DS. This improvement was observed only under moderate temperature resulting in significant (p<0.05) energy by temperature interaction. High protein significantly (p<0.05) increased BW, WG, CW and BM, decreased AF but did not affect FI, FC, TP, DS, or TH. There were no significant protein by temperature interactions for any of the parameters tested except CW. It is concluded, under the conditions imposed in this experiment, that increasing dietary energy did not alleviate the depressing effect of heat stress while increasing dietary protein up to 22% improved the performance of broilers irrespective of rearing temperature.

• The Korean Journal of Malacology
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• v.16 no.1_2
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• pp.31-34
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• 2000

A series of rearing experiments have been conducted to determine the growth and survival rate in accordance with body size in closed recirculating sea water system. The abalone, Sulculus aquatilis, spat of 10.24${\pm}$0.85 mm, 0.36${\pm}$0.l g and 24.9${\pm}$1.07 mm 2.07${\pm}$0.57 g in shell length and body weight were used in this study Ranges of water temperature and pH during the rearing period of 90 days were 10.0-24.2$^{\circ}C$ and 7.8-8.2, respectively. Dissolved oxygen during the experiment period was 6.13-7.21 ml/l and inorganic nitrate was 0.68-3.72 $\mu\textrm{m}$ in NH$_4$$\^$+/-N, 0.17-7.79 fm in NO$_2$-N and 0.4-11.52 $\mu\textrm{m}$ in NO $_2$-N, Growth in shell length and body weight of the spat in large group and small group at the end of the experiment were 30.80${\pm}$3.14 mm, 17.98${\pm}$2.61 mm and 3.20${\pm}$0.8 g, 0.36${\pm}$0.1 g, and survival rate of spat in large group and small group at the end of the rearing experiment were 96.0% and 90.0% , respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.195-206
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• 1980

Fish were grown in a water recycling rearing system consisting of a filter system, of which the area is about $30\;m^2$ and the volume of filter gravels is about $15\;m^3$, 6 rearing and 2 supplementary tans about $7\;m^2$ of surface area each. The results for 180 days from April 18 to October 14,1980 are summarized as following: One rearing tank was used for main experiment stocked with an equal number, and weight of each Israeli strain and $F_1$, hybrid between this strain and Korean local strain of common carp. Gross total production was 461 kg with a net production of 395 kg, and the Israeli strain grew to about 8 times initial weight and the hybrid about 6 times. Based on an analysis of results of the above mentioned main experiment and the other miscellaneous fish grown in the remaining tanks, it was considered to be feasible to implement a commercial production in this system by improving parts of the system and adding a number of the units. A special problem seems to be an adoption of more effective aeration device when fish loading increases. A solid waste removal system was deviced by use of by-pass flow ana this system worked very efficiently in view of supply water economy. A serious problem encountered in this experiment was heavy outbreaks of the gill-fluke, Dactylogyrus sp. which was relatively easily eradicated with Dipterex or DDVP treatment in the first trials, but later on strains which were resistant to any of these chemicals appeared.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.233-238
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• 1981

A recirculating water system without filter bed was used for a high density experimental rearing of common carp, Cyprinus carpio, during the summer of 1981. Of the water system, 3 tanks were used for stocking each tank with 10,000, 20,000 and 30,000 common carp fingerlings which averaged 0.6 g. The water in the system was maintained in dark green colour by heavy growth of phytoplankton during the most period of the experiment. In this experiment, the best daily growth rate, $3.7\%$, was obtained from the 10,000 fish group followed by $2.8\%\;and\;3.0\%$ from the 20,000 and 30,000 fish groups respectively. Thus there was no significant difference between the latter two groups. Especially, notably high concentration of total ammonia, $5\sim7$ ppm ammonia-N, in the culture water appeared during the most experimental period, but this did not seem to have affected feeding and growth of the fish when the water was kept at heavy bloom. It was also obvious that the outbreak of columnaris disease was effectively depressed in this green water recirculating system compared to that in clarified recirculating system. One tank ($7m^2$) of this system was stocked with 446 common carp of intermediate size averaging 352.2 g and after 40 day rearing they grew to 486.3 g in average with a daily growth rate of $0.8\%$. This result was a little inferior to that reared in a tank of the clarified water system as control which showed $1.0\%$ daily growth rate. Therefore, before an initiation of the commercial production of fish in this method, further studies concerning the amount of ammonium with its effect on the fish under rearing in this system and the columnaris disease problem should be carried out.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.465-472
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• 2001

The effects of water level reduction in rearing tank and fish transference during fish selection process on the stress response (hematological factors, cortisol, glucose, lactic acid and osmolality) of tank-reared olive flounder Paralichthys olivaceus of large (FL), small (FS) and Japanese croaker, Nibea japonica (JC) were examined in running seawater culture system. The water level of rearing unit was lowered from 33 cm to 8 cm in the course of 2 minutes in the water level reduction experiment. The fish were removed from rearing tank (12 ton) to 450 L tank in 30 seconds after capture in the fish transference experiment, In water level reduction, the hematocrit of FL was significantly increased from $14.6\%$ at beginning to $23.5\%$ after 10 hours, However, it decreased to the value of beginning after 46 hours. Plasma cortisol concentration of FL was the highest concentration (13.7 ng/mL) after 22 hours, but it decreased to 4.0 ng/mL at the end of experiment. Cortisol concentration of FS did not show any significant difference during the experiment. The cortisol concentration of JC were significantly higher at 4 hours (282.3 ng/mL) and 22 hours (350.5 ng/mL), Glucose concentration of JC was the highest (138.0 mg/dL) at 22 hours. Lactic acid concentration was not different between experimental groups. In the fish transference experiment, red blood cell of FL was increased from $1.9\times10^6\;cell/{\mu}\;L\;to\;4.2\times10^6\;cell/{\mu}L$ in 24 hours. Blood hemoglobin of JC were significantly elevated in 24 hours. At 1 hour after transference, plasma cortisol concentrations in both fish species were increased to 95.3 ng/mL in FL and 175.5 ng/mL in JC. Glucose concentration of JC was increased to 132.5 mg/dL at 1 hour, 129.5 mg/dL at 3 hours after transference.

• Journal of Sericultural and Entomological Science
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• v.16 no.2
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• pp.1-34
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• 1974

These experiments pertain to various factors influencing the quantitative characters of cocoon crops in summer and early autumn seasons. Initially, in order to establish the possible ways of the silkworm rearing more than three times a year in Korea, the author attempted to get further information about the various factors affecting the cocoon crop in every silkworm rearing season. The trials were conducted eleven times a year at four places for three years. The field trial was conducted with 19 typical sericultural farmers who had been surveyed. At the same time the author statistically analyzed the various factors in close relation to tile cocoon crop in autumn season. The effect of guidance on 40 sericultural farmers was analyzed, comparing higher level farmers with lower level farmers ; and the author surveyed 758 non-guided farmers near the guided farmers during both spring and autumn seasons. In addition, another trial on the seasonal change of leaf quality was attempted with artificial diets prepared with leaves grown in each season. It was found that related factors to cocoon crops in summer and early autumn seasons appeared to be leaf quality, and temperature for young and grown larvae. A 2$^4$ factorial experiment was designed in summer season, and another design with one more level of varied temperature or hard leaf added to a 24 factorial experiment was conducted in early autumn. The experimental results can be summarized： 1. Study on the cocoon crops in the different rearing seasons 1) It was shown that earlier brushing of silkworm generally produced the most abundant cocoon crop in spring season, and earlier or later than the conventional brushing season, especially earlier brushing was unfavorable for the abundant cocoon crop in autumn season. 2) The cocoon crop was affected by the rearing season, and decreases in order of sire with spring, autumn, late autumn, summer and early autumn seasons. 3) It was Proved that ordinary rearing and branch rearing were possibles 4 times a year ; in the 1st, 3rd, 8th, and 10th brushing season. But the 11th brushing season was more favorable for the most abundant cocoon crop of branch rearing, instead of the 10th brushing season with ordinary rearing. 2. Study on the main factors affecting the cocoon crop in autumn season 1) Accumulated pathogens were a lethal factor leading to a bad cocoon crop through neglect of disinfection of rearing room and instruments. 2) Additional factors leading to a poor cocoon crop were unfavorable for rearing temperature and humidity, dense population, poor choice of moderately ripened leaf, and poor feeding techniques. However, it seemed that there was no relationship between the cocoon crop and management of farm. 3) The percentage of cocoon shell seemed to be mostly affected by leaf quality, and secondarily affected by the accumulation of pathogens. 3. Study on the effect of guidance on rearing techniques 1) The guided farms produced an average yearly yield of 29.0kg of cocoons, which varied from 32.3kg to 25.817g of cocoon yield per box in spring versus autumn, respectively. Those figures indicated an annual average increase of 26% of cocoon yield over yields of non-guided farmers. An increase of 20% of cocoon yield in spring and 35% of cocoon yield in autumn were responsible. 2) On guided farms 77.1 and 83.7% of total cocoon yields in the spring and autumn seasons, respectively, exceeded 3rd grade. This amounted to increases of 14.1 and 11.3% in cocoon yield and quality over those of non-guided farms. 3) The average annual cocoon yield on guided farms was 28.9kg per box, based on a range of 31.2kg to 26.9kg per box in spring and autumn seasons, respectively. This represented an 8% increase in cocoon yield on farms one year after guidance, as opposed to non-guided farms. This yield increase was due to 3 and 16% cocoon yield increases in spring and autumn crops. 4) Guidance had no effect on higher level farms, but was responsible for 19% of the increases in production on lower level farms. 4. Study on the seasonal change of leaf quality 1) In tests with grown larvae, leaves of tile spring crop incorporated in artificial diets produced the best cocoon crop; followed by leaves of the late autumn, summer, autumn, and early autumn crops. 2) The cocoon crop for young larvae as well as for grown larvae varied with the season of leaf used. 5. Study on factors affecting the cocoon crops in summer and early autumn A. Early autumn season 1) Survival rate and cocoon yield were significantly decreased at high rearing temperatures for young larvae 2) Survival rate, cocoon yield, and cocoon quality were adversely affected by high rearing temperatures for grown larvae. Therefore increases of cocoon quantity and improvement of cocoon quality are dependent on maintaining optimum temperatures. 3) Decreases in individual cocoon weight and longer larval periods resulted with feeding of soft leaf and hard leaf to young larvae, but the survival rate, cocoon yield and weight of cocoon shell were not influenced. 4) Cocoon yield and cocoon quality were influenced by feeding of hard leaf to grown larvae, but survival rate was not influenced by the feeding of soft leaf and hard leaf. 5) When grown larvae were inevitably raised at varied temperatures, application of varied temperature in the raising of both young and grown larvae was desirable. Further research concerning this matter must be considered. B. Summer season 1) Cocoon yield and single cocoon weight were decreased at high temperatures for young larvae and survival rate was also affected. 2) Cocoon yield, survival rate. and cocoon quality were considerably decreased at high rearing temperatures for grown larval stages.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.249-255
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• 2008

The experiment was conducted to determine effect of the mixed herbal medicine for the substitution of antibiotics on the performance of laying hens. Day old hyline 1,500 layer chicks were randomly assigned to 4 treatments. Control were 600 chicks and there were three treatments of each 300 chicks. The 4 treatments were as follows: the mixed herbal medicine 0.1%(T-1), 0.3%(T-2) and 0.5%(T-3) after removed antibiotics on commercial feed and commercial feed( control) from 5th week to 13th week, each treatment was replicated 3 times and from 14th week to 18th week. Each 100 hens of the mixed herbal medicine 0.1%(CT-1), 0.3%(CT-2) and 0.5%(CT-3) were moved to cage. Body weight were measured on 4th, 8th, 13th week and feed intake, mortality were measured on every weeks. Body weight at fourth week, all treatments tended to be higher than control and T-3 statistically was highest(p<0.01). On 8th week, also treatments statistically high and T-1 was highest(p<0.01). But 12th week, there was not significantly different among treatments. Therefore it will be possible that the mixed herbal medicine substitute for antibiotics after vaccination. Mortality was not different between treatment and control overall rearing period. Early laying period($19{\sim}41wk$), T-2 showed highest feed intake(107.1g) among treatments, later laying period($42{\sim}77wk$), T-1 showed highest feed intake(134.3g) and was not any different among each treatments.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.1
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• pp.49-59
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• 2017

The objective of this study was to investigate the growth rate and the optimal stocking density of sea cucumbers. Grow-out was studied in situ by conducting a follow-up survey using visible implant elastomer (VIE) tags. The rearing systems were made of polypropylene pipe for the frames and netting. The experiment ran for 70 days near Yeosu, Korea in the water depth of about 7 m. A total of 576 sea cucumbers which have three groups of body sizes (small: 5.15, medium: 12.34 and large: 23.26 g) were used. The five groups of stocking densities (150, 300, 450, 600 and $850g/m^2$) in rearing system for sea cucumber were considered. Sea cucumbers were fed a mixed diet (mud, mineral, fish meal, etc.). The feed was supplied to 10% of their body wet weight once every 7 days. The survival rate (73%) of sea cucumber in $850g/m^2$ was lower than those of other density groups ($150g/m^2$: 89%, $300g/m^2$: 84%, $450g/m^2$: 78% and $600g/m^2$: 86%). The survival rate of medium size group was higher than those of small and large groups regardless of the density (P<0.05). Most of density groups have no significant difference except for $850g/m^2$ (P>0.05). The growth rate of small size group ($0.63%day^{-1}$) was higher than those of medium ($0.38%day^{-1}$) and large ($0.34%day^{-1}$) group regardless of the density (P<0.05). The threshold water temperature was $11.0^{\circ}C$ for sea cucumber growth in winter season.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.275-279
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• 1977

During the experimental rearing period of common carp in a small simple recirculating aquarium combined with frequent exchanges of water and cleanings, some observations were made on the conditions of fish growing which was directly and instantly affected by the cleaning frequency of strainer, changing rate of water, division and frequency of feed supply, prohibition of excess feeding and the amount of dissolved oxygen. The fish don't seem to be stressed by the manipulation for the change of rearing water, cleaning of detritus in the strainer and filter. It appeared that the most hazzardous matters to fish growth were : 1) supplying feed when fish do not show active response to feed supplied, and 2) giving ample amount of feed at one time. When especially the amount of the feed is within the range fish instantly can swallow, the water clarity is maintained even after feeding operation, but if any excess amount is given the fish intake into mouth much more feed than able to instantly swallow and try to swallow it resulting in much dissolving and suspension of feed materials in water, making the water quite cloudy. Consequently all the water as well as filter bed becomes significantly polluted.

• Journal of Aquaculture
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• v.7 no.1
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• pp.9-20
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• 1994

To find out suitable indoor rearing tank shape and stocking density of the abalone Haliotis discus hannai, young abalones were reared in the square or ellipse shape tanks with various stocking densities and were fed dried sea mustard, Undaria Pinnatifida HARVEY for three years. There were no significant differences between the square rearing tank and the ellipse one in growth rate and survival rate. With regard to vertical design of rearing tanks with three floors, the significant differences were not found among culture floors. However, the growth and survival rates of young abalones from the running water system were significantly higher than those of the abalones from the circulating system (P< 0.05). For the stocking density experiment with 1,000, 1,500 and 2,000 individuals of 20 mm young abalone, there was no significant differences in growth and survival rates among these groups. However, in that of 200-400 individuals of 40 mm abalone and 100-300 individuals of 50 mm abalone, the lower stocking density of young abalone showed the higher growth and survival rates. The lower stocking density and the smaller size of young abalones showed the higher daily feeding rate and feed efficiency.