• Journal of Aquaculture
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• v.5 no.1
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• pp.29-67
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• 1992

Life cycle and seed production of the freshwater prawn, Macrobrachium nipponense, were studied and the results are as follows : 1. Larval development : Embryos hatched out as zoea larvae of 2.06 mm in mean body length. The larvae passed through 9 zoea stages in $15{\~}20$ days and then metamorphosed into postlarvae measuring 5.68 mm in mean body length. Each zoea stage can be identified based on the shapes of the first and second antennae, exo- and endopodites of the first and second pereiopods, telson and maxillae. 2. Environmental requirements of zoea larvae : Zoea larvae grew healthy when fed with Artemia nauplii. Metamorphosing rate was $65{\~}72{\%}$ at $26{\~}28\%$ and $7.85{\~}8.28\%_{\circ}Cl.$. The relationship between the zoeal period (Y in days) and water temperature (X in $^{\circ}C$) is expressed as Y=46.0900-0.9673X. Zoeas showed best survival in a water temperature range of $26{\~}32^{\circ}C$ (optimum temperature $28^{\circ}C$), at which the metamorphosing rate into postlarvae was $54{\~}72\%$ The zoeas survived more successfully in chlorinity range of $4.12{\~}14.08{\%_{\circ}}Cl.$, (optimum chlorinity $7.6{\~}11.6\;{\%_{\circ}}Cl.$.), at which the metamorphosing rate was $42{\~}76{\%}$. The whole zoeal stages tended to be longer in proportion as the chlorinity deviated from the optimum range and particularly toward high chlorinity. Zoeas at all stages could not tolerate in the freshwater. 3. Environmental requirements of postlarvae and juveniles : Postlarvae showed normal growth at water temperatures between $24{\~}32^{\circ}C$ (optimun temperature $26{\~}28^{\circ}$. The survival rate up to the juvenile stage was $41{\~}63{\%}$. Water temperatures below $24^{\circ}C$ and above $32^{\circ}$ resulted in lower growth, and postlarvae scarcely grew at below $17^{\circ}C$. Cannibalism tended to occur more frequently under optimum range of temperatures. The range of chlorinity for normal growth of postlarvae and juveniles was from 0.00 (freshwater) to $11.24{\%_{\circ}}Cl.$, at which the survival rate was $32{\~}35\%$. The postlarvae grew more successfully in low chlorinities, and the best growth was found at $0.00\~2.21{\%_{\circ}}Cl.$. The postlarvae and juveniles showed better growth in freshwater but did not survive in normal sea water. 4. Feeding effect of diet on zoea Ilarvae : Zoea larvae were successfully survived and metamorposed into postlarvae when fed commercial artificial plankton, rotifers, and Artemia nauplii in the aquaria. However, the zoea larvae that were fed Artemia nauplii and reared in Chlorella mixed green water showed better results. The rate of metamorphosis was $68\~{\%}75$. The larvae fed cow live powder, egg powder, and Chlorella alone did not survive. 5. Diets of postlarvae, juveniles and adults : Artemia nauplii and/or copepods were good food for postlarvae. Juveniles and adults were successfully fed fish or shellfish flesh, annelids, corn grain, pelleted feed along with viscera of domestic animals or fruits. 6. Growth of postlarvae, juveniles and adults : Under favorable conditions, postlarvae molted every five or six days and attained to the juvenile stage within two months and they reached 1.78 cm in body length and 0.17 g in body weight. The juveniles grew to 3.52 cm in body length and 1.07 g in body weight in about four months. Their sexes became determinable based on the appearance of male's rudimental processes (a secondary sex character) on the endopodites of second pereiopods of males. The males commonly reached sexual maturity in seven months after attaining the postlarvae stage and they grew to 5.65 cm in body length and 3.41 g in body weight. Whereas the females attained sexual maturity within six to seven months, when they measured 4.93 cm in body length and 2.43 g in body weight. Nine or ten months after hatching, the males grew $6.62{\~}7.14$ cm in body length and $6.68{\~}8.36$ g in body weight, while females became $5.58{\~}6.08$ cm and $4.04{\~}5.54$ g. 7. Stocking density : The maximum stocking density in aquaria for successful survival and growth was $60{\~}100$ individuals/$\ell$ for zoeas in 30-days rearing (survival rate to postlarvae, $73{\~}80{\%}$) ; $100{\~}300$ individuals/$m^2$ for postlarvae of 0.57 cm in body length (survival rate for 120 days, $78{\~}85{\%}$) ; $40{\~}60$ individuals/$m^2$ for juveniles of 2.72 cm in body length (survival rate for 120 days, $63{\~}90{\%}$) : $20{\~}40$ individuals/$m^2$ for young prawns of 5.2 cm in body length (survival rate for 120 days, $62\~90{\%}$) ; and $10\~30$ individuals/$m^2$ for adults of 6.1 cm in body length (survival rate for 60 days, $73\~100{\%}$). The stocking density of juveniles, youngs and adults could be increased up to twice by providing shelters.

• Korean Journal of Poultry Science
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• v.12 no.1
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• pp.7-16
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• 1985

Present experiment was undertaken to compare the effects of two dietary fats whose free fatty acid content was quite different on performances and on meat quality of broilers. Yellow grease or animal fat (trade name) containing 15 or 38.6% free fatty acid, respectively, was added to the broiler starter and finisher diets at levels of 3.0 and 5,0%, respectively. A total of 108, day old, male Maniker(Chunho) broiler chicks was alloted to 3 dietary treatments with 3 replications per treatment and 12 chicks per replication Though control diet was not supplemented with fat, the three dietary groups were made isocaloric and isonitrogenous. All the chicks were ad libitum fed the test diets for 8 weeks. Feed intake and body weight were measured every other week. Shank color was measured at the end of feeding trial by Roche Color Fan. To evaluate meat quality, 7 chicks of mean body weight were selected from each treatment group after the trial. Measurements were made for abdominal fat content, organoleptic scores for thigh and breast, and for contents of total lipids, free fatty acids, iodine values and peroxide values of the breasts. During the period from 0 to 4 weeks of age, the broilers fed the diets added with fats performed the same as those fed the control diet. However, the body weight gam (25%), feed intake (10.8%) and feed efficiency (11.3%) of chicks fed the fat-supplemented diets, during the finisher period (5-8 weeks), appeared significantly improved compared to those of control group (p＜0.05). During overall period of 8 weeks, body weight gain, feed intake, and feed efficiency of chicks fed the diets added with fats were, on the average, 16.2. 8.8 and 6.8%, respectively, better than, those of control Monwhile the performance between the chicks fed diets added with the two different fat sources appeared to be of the same tendency. Though the shank pigmentation was not statistically different among the treatments, the chicks fed the fat-supple ented diets tended to have slightly less pigments than the control. Organoleptic scores of thigh or breast of chicks fed the animal fat diet were of the same range as those of the other two groups. The contents of total lipids, free fatty acids, iodine values and peroxide values of breasts from broilers fed the various diets appeared to be in the same ranges among the treatments. The values for control, yellow grease and animal fat groups were 7.77, 6.66 and 6.32% for total lipids, 9.23, 9.7 and 9.31mg oleic acid/g fat for free fatty acids, 65.36, 63.89 and 59.25g/ 100g fat for iodine values, and 9.62, 10.46 and 8.79 meq/kg fat for peroxide values, respect vely. Changes of free fatty acids contents of breast during a storage for 10 da s at 4$^{\circ}C$ were also not different among the dietary groups. From the observations n. this experiment, it seems possible to conclude that the animal fat containing 38.6% free fatty acid can be used as efficiently as yellow grease in broiler diets without any adverse effects on meat quality.

• Korean journal of applied entomology
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• v.19 no.1 s.42
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• pp.57-65
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• 1980

The oriental tobacco budmoth, Heliothis assulta Guenee were reared under various temperatures; $20^{\circ}C,\;25^{\circ}C,\;30^{\circ}C$ and the control effects of Thuricide $HP^{(R)}$ were examined. The results obtained were as fellows: 1. The adult longevity of oriental tobacco budmoth was 11.35 days, and 3.00 days for preovipositional period, 4.75 days for ovipositional Period, and 3.50 days for postovipositional period. 2. The total number of eggs laid by a female were 307 at $20^{\circ}C$, 413 at $25^{\circ}C$ and 189 at $30^{\circ}C$. The number of eggs per female per day were 64.05 in average. 3. The average egg Periods were 7.71 days at $20^{\circ}C$, 4.12 days at $25^{\circ}C$ and 3.58 days at $30^{\circ}C$ and the hatchiabilities were $71.25\%,\;78.49\%\;and\;81.05\%$ at the respective incubation temperatures. 4. The larval developmental periods were 43.51 days at $20^{\circ}C$, 21.79 days at $25^{\circ}C$ and 18.05 days at $25^{\circ}C$ and the mortalities were $80.70\%,\;95.93\%$ and $87.01\%$ at the respective temperatures. 5. The pupal developmental periods were 24.22 days at $20^{\circ}C$, 12.36 days at $25^{\circ}C$ and 11.50 days at $30^{\circ}C$ and the mortalities at the respective temperatures were $18.18\%,\;42.11\%\;and\;40.00\%$. 6. The calculated threshold temperatures for the development were $11.61^{\circ}C$ for the eggs, $11.96^{\circ}C$ for the larvae, and $10.06^{\circ}C$ for the pupae. The estimated total effective temperatures were 60.41 day degrees for e eggs, 319.35 day degrees for the larvae, 222.66 day degrees for the pupae, and overall total effective temperatures, however, would be ranged 640-660 day degrees if the reproductive period of the adult was considered. 7. The relationship between the overall developmental periods and the rearing temperature could be Y=-4.272X+155.39 (r=0.9105), where Y; number of days required to complete the life cycle, X; treated temperatures. 8. The control effects of Thuricide $HP^{(R)}$ were $73.43\%$ for spray and $58.22\%$ for bait applications.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.777-786
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• 2003

An experiment was conducted to investigate the effects of supplementary Blended essential oil(CRINA$^{\circledR}$) on the performance, nutrient availability, fatty acid composition of leg muscle, small intestinal microflora and blood parameters in broiler chickens. One thousand unsexed day-old broiler chickens were assigned to five treatments : control(T1), 5ppm avilamycin(starter diet) & 5ppm flavomycin(grower diet) T2, 5ppm avilamycin(starter diet) & 50ppm CRINA$^{\circledR}$(grower diet) T3, 50ppm CRINA$^{\circledR}$(starter & grower diet) T4, 50ppm CRINA$^{\circledR}$+ 500ppm lactic acid$^{\circledR}$ (starter & grower diet) T5. Each treatment had four replications of 50 birds each. Growth performance was significantly improved by dietary supplements(T2-T5). There were no significant differences among treatment T2, T3, T4 and T5. Feed intake was not significantly different among treatments. Dietary supplementation of CRINA$^{\circledR}$(T3, T4, T5) resulted in significant(p〈0.05) improvement in feed/gain(F/G) during finishing period (4-5weeks). The birds fed CRINA$^{\circledR}$ supplemented diet(T4) showed significantly(p〈0.05) higher availability of crude fat, methionine and methionine + cystine than those fed antibiotics supplemented diet(T2). Mortality was not significantly affected by treatments. The colony forming unit(CFU) of E.coli in small intestinal content was significantly lower in antibiotics & CRINA$^{\circledR}$(T3) compared to CRINA$^{\circledR}$ treatment(T4)(P〈0.05). CFU of Cl. perfringens was low in CRINA$^{\circledR}$(T4) but not different significantly with other treatments. Serum triglyceride level of birds fed CRINA$^{\circledR}$ + lactic acid diet(T5) was significantly lower(p〈0.05) than those fed antibiotics supplemented diet(T2). Cholesterol level of the birds fed antibiotics(T2) or CRINA$^{\circledR}$ + lactic acid supplemented diet(T5) was significantly higher(p〈0.05) than other treatments. HDL level of birds fed control diet was significantly lower(p〈0.05) than that of others. The levels of serum IgG were not significantly different among treatments. Major fatty acids composition of leg muscle fat was significantly influenced by treatments. Control group showed significantly higher palmitic acid(C$_{16:0}$) and steraric acid(C$_{18:0}$) content than other treatments(p〈0.05). Content of oleic acid(C$_{18:1}$), however, was significantly lower in the control than others treatments. Content of linolenic acid(C$_{18:3}$) was significantly higher in CRINA$^{\circledR}$+ lactic acid(T5) than antibiotics & CRINA$^{\circledR}$(T3) treatments. Total saturated fatty acids content was higher and total unsaturated fatty acids were lower in the leg muscle fat of the control than that of other treatments. It is concluded that CRINA$^{\circledR}$ supplementation improved growth rate and F/G ratio in broilers. The combination of CRINA$^{\circledR}$ with either antibiotics or lactic acid did not show any additive or synergistic effects in broiler chickens .

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.2
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• pp.97-114
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• 1977

The fresh water prawn, Macrobrachium rosenbergi(de Man) is a very common species in Indopacific region, which inhaits both fresh and brackish water in low land area, most of rivers and especially aboundant in the lower reaches which are influenced by sea water. It is one of the largest and commercial species of genus Macrobrachium, which is commonly larger than $18\~21cm$ in body length, from the basis of eye-stalked to the distal of telson. As a part of the researches in order to investigate the possibilities on transplantation and propagation of this species, this work dealt with the problems on the effects of chlorinities upon zoeal larvae and post-larvae 1). metamorphosis rate and optimum chlorinity for metamorphosis to post-larve, 2). tolerance and comparative survival rate on various chlorinties, from fresh water to sea water $(19.38\%_{\circ}\;Cl)$, which reared for six days upon each stage of zoeal larvae, 3). accomodation rate on chlonities which reared for twelve days after transmigration into variant chlorinities of the range from $3.68\%_{\circ}$ Cl to $1.53\%_{\circ}$ Cl in the way of rearing of the range from $3.82\%_{\circ}$ Cl to $11.05\%_{\circ}$ upon each stage of zoea, 4). tolerance on both of fresh and sea water upon zoeal larva and post-larva under the condition of $28^{\circ}C{\pm}1$ in temperature and feeding on Artenia salina nauplii, 5). relationship between various chlorinities and grwth of post-larvae under the condition of $28^{\circ}C$ in tmperature and feeding on meat of clam. Thus these investigations were performed in order to grope for a comfortable method on seedmass production. Up to the present, the study on the effects of chlorinity upon earlier zoeal larvae and post-larvae of Macrobrachium species has been scarcely performed by workers with the exception of Lewis(1961) and Ling (1962,, 1967), even so their works were not so detailed. On the other hand, larvae of several species of this genus were reared at the water which mixed sea water so as to carry out complete metamorphosis to post-larva by workers in order to investigate on earlier 1 arval and earlier post-larval development, such as Macrobrachium lamerrei (Rajyalakshmi, 1961), M. rosenbergi and M. nipponense (Uno and Kwoa, 1969; Kwon and Uno, 1969), M. acanthurs (Choudhury, 1970; Dobkin, 1971), M. carcinus(Choudhury, 1970), M. formosense(Shokita, 1970), M. olfersii (Duggei et al., 1975), M. novaehallandiae (Greenwood et al., 1976), M. japonicum (Kwon, 1974) and M. lar (Shokita, personal communication), and there fore it is regarded that chlorinity is, generally, one of absolute factors to rear zoeal larvae of brackish species of Macrobrachium genus. Synthetic results on this work is summarized as the follwings: 1) Zoeal larvae required different chlorinities to grow according to each stage, and generally, it is regarded that optimum range of living and growing is from $7.63\%_{\circ}Cl\to\;7.63\%_{\circ}Cl$, and while differences of metamorphsis rate, from first zoea to post-larva, is rarely found in this range, and however it occurs apparently in both of situation at $7.63\%_{\circ}Cl$ below and $16.63\%_{\circ}Cl$ above and moreover, metamorphosis rate is delayed somewhat in case of lower chlorinity as compared with high chlorinity in these situations. 2) Accomodation in each chlorinity on the range, from fresh water to sea water, is different according to larval stages and while the best of it is, generally, on the range from $14.24\%_{\circ}Cl$ to $8.28\%_{\circ}Cl$ and favorite chlorinity of zoea have a tendency to remove from high chlorinity to lower chlorinity in order to advance larval age throughout all zoeal stages, setting a conversional stage for eighta zoea stage. 3) Optimum chlorinity of living and growth upon postlarvae is on the range of $4.25\%_{\circ}Cl$ below, and in proportion as approach to fresh water, growth rate is increased. 4) Post-large are able to live better in fresh water in comparison with zoeal larvae, which are only able to live within fifteen hours, and by contraries, post-larvae are merely able to live for one day as compared with ?미 larvar, which are able to live for six days more in sea water $19.38\%_{\circ}Cl\;above$. 5) Also, in case of transmigration into higher and lower chlorinities in the way of rearing in the initial chlorinities $ 3.82\%_{\circ}Cl,\;7.14%_{\circ}Cl\;and\;11.05%_{\circ}Cl$, accoodation rate is a follow: accomodation capacity in ease of removing into higher chlorinities from lower chlorinities is increased in proportion as earlier stages, setting a conversional stage for eighth zoea stage, and by contraries, in case of advanced stages from eighth zoea it is incraesed in proportion as approach to post-larva stage in the case of transmigration into lower chlorinity from higher chlorinity. On the other hand, it is interesting that in case of reciprocal transmigration between two different chlorinitiess, each survival rate is different, and in this case, also, its accomodation in each zoea stage has a tendency to vary according to larval stages as described above, setting a conversional stage for eighth zoea stage. 6) It is likely that expension of radish pigments on body surface is directly proportional to chlorinity during the period of zoea rearing, and therefore it seems like all body surfacts of zoea larvae be radish coloured in case of higher chlorinity. 7) By the differences that each zoeal larvae, postlarvae, juvaniles and adult prawn are required different chlorinity for inhabiting in each, it is regarded that this species migrats from up steam to near the estuary of the river which the prawns inhabits commonly in natural field for spawning and growth migration. 8) It had better maintainning chlorinities according to zoeal stage for a comfortable method on seed-mass production that earlier larva stages than eighth zoea are maintained on the range from $8\%_{\circ}Cl\;to\;12\%_{\circ}Cl$ to rear, and later larva stages than eighth zoea, by contraries, are gradually regula ted-to love chlorininity of the range from $7\%_{\circ}Cl\;to\;4\%_{\circ}Cl$ according to advance for post-larva stage.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.2
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• pp.71-97
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• 1974

Many studies on the changes of the materials in the water-logged paddy soil have been reported, but there will be several problems to apply them on the field soil. The main differences between the method of soil packed in beaker or column tube to that of natural field furrow slice are with or without of the rice root and the effect of water percolation. On the other hand, the mechanism of the water percolation on the changes of material in the natural field furrow slice are gradually understood. The purpose of this experiment is to know the effect of the rice cultivation on the chemical and physical changes of material in the water-logged paddy soil. Obtained results are as follows. 1. The physical and chemical changes on the water-logged paddy soil in the non-planted control-plot were nearly the same as the beaker or column tube experiment, while in the planted plot, slightly altered patterns were observed. 2. The relation between the number of tillers and total cation, $Ca^{{+}{+}}$, $Mg^{{+}{+}}$, Fe and Mn in the leachate showed very high significance. T hisresult showed that the leaching of those cation was promoted by growing of the rice r- of the rice root. 3. On the other hand, the concentration of the potassium, silica and phosphorus in leachates was gradually decreased and that of $NH_4$-N could not detect after the stage of active tillering. These facts revealed that such components were absorbed by rice plant. 4. The highly significant correlation between the number of tillers and the concentration of the total cation, $Ca^{{+}{+}}$, $Mg^{{+}{+}}$, $Fe^{{+}{+}}$, Fe and Mn in the percolated water was observed except that of $Mg^{{+}{+}}$. It was also showed that the rice root promoted the leaching of those cation. 5. The very high significance in the correlation between $HCO_3{^-}$ and the number of tillers indicated that the higher activity of the rice root was, the more $HCO_3{^-}$ concentration in the leachate was increased. 6. The relationship between the $HCO_3{^-}$ and the total cation, $Ca^{{+}{+}}$, $Mg^{{+}{+}}$, $Fe^{{+}{+}}$, Fe and Mn was appeared very highly significant. $HCO_3{^-}$, the metabolite of the rice root, promoted the leaching of $Ca^{{+}{+}}$, $Mg^{{+}{+}}$, $Fe^{{+}{+}}$ and Mn. This fact might be a result that these cations were leached as the form of bicarbonate. 7. The iron in the leachate was the form of $Fe^{{+}{+}}$ and the correlation between $Fe^{{+}{+}}$ and $HCO_3{^-}$ was very highly significant. This result indicated that it seemed to be ferrous bicarbonate when it is leached out. 8. In the rhizosphere, ferrous iron was decreased gradually and the concentration of glucose was as high as 2 to 3 times in comparison with the other parts of the soil. These facts were the same as the previous reports in which rhizosphere was oxidized by the oxigen excreted from the root, and was enriched by the organic matter which was also excreted from the root and accumulated residues of the root. 9. ${\beta}$-Glucosidase and phosphatase activity in the rhizosphere was higher than that of the other parts of the soil. This facts might be attributed to the vigorous activity of microorganism in the rhizosphere where glucose concentration was high. 10. The pH in the leachate of the planted plot was lower than that of control, and the Eh on the planted soil was elevated in the last stage.