• Journal of Aquaculture
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• v.20 no.3
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• pp.194-198
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• 2007

Reproductive traits of Palaemon gravieri such as embryo size, number of embryo (fecundity), incubation period, larval development mode, larval development period, larval survival and larval growth were described and compared to analyze the correlation among those traits. Embryo volume is a primary factor determining other ensuing reproductive features. Egg volume was $0.042mm^3$ in the first developmental stage. Embryo volume in P. gravieri was comparatively small which is indicative of great number of embryo (y = 3.0161x + 0.0185 $R^2$ = 0.74 positive isometric relationship) and relatively long incubation period. Larvae survived from zoea 1 to post-larvae and it took 45 days at $22^{\circ}C$. Survival rate of the larvae was rather great in the early stage and thereafter steadily decreased. Daily growth rate of larvae in P. gravieri at $22^{\circ}C$ was 0.0195 mm on average. They grew steadily as time went by. Incubation period was between 10-14 days at $22^{\circ}C$. Larval development mode was almost complete planktotrophic. PNR (point of no return) appeared to be the third day on average. Survival rate of larvae without feeding declined rapidly between 3 and 4 days. Larval development period and stage frequency were 23-30 days and 11 stages which imply prolonged larval period and high mortality. The pattern of brood production followed fast successive parturial pattern. Most ovigerous female had mature ovary when they performed parturial molt soon after hatching (larval release).

• Animal cells and systems
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• v.3 no.4
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• pp.369-374
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• 1999

The life history and development of Tetrastichus sp. parasitizing fallwebworm pupa in Korea were studied. The mean lifetime fecundity was 94.7 with a maximum of 125, and the portion of female progeny averaged 90.3%. A male and a female lived for an average of 19.8${\pm}$4.5 and 21.7${\pm}$4.2 days, respectively. The duration of development for each stage was as follows: egg, 2 d; the 1st instar larva, 2${\pm}$1 d; the 2nd instar larva, 2${\pm}$1 d: the 3rd instar larva, 3${\pm}$1 d; the 4th instar larva, 6${\pm}$2 d; and pupa, 8${\pm}$2 d. Total developmental duration from hatching of the larva to adult emergence required 21.1${\pm}$3.7 d, and females took 1-2 days more than males in the incubator (28$^{\circ}C$, 70% RH, and 16:8 LD).

• Journal of Ecology and Environment
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• v.31 no.1
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• pp.9-15
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• 2008

Growth and reproduction of Palaemon serrifer were described and analyzed in a population inhabiting tide pools in warm temperate waters in Korea. The water temperature varied greatly in the tide pools, ranging from 8$^{\circ}C$ to 27.8$^{\circ}C$ Population structure and growth were investigated using size frequency distribution data collected from January to December 2003. Sex ratios fluctuated, but were almost equal during the breeding period. Growth was continuous and size increased gradually throughout the year. Adult females were larger and grew faster than males. von Bertalanffy growth parameters for a one-year sample of females and males were estimated as $L_{i\ddot{A}}$ = 11.32, K = 0.311, $t_0$ = -0.4115 and $L_{i\ddot{A}}$ = 8.36, K = 0.228, $t_0$ = -0.9693 respectively. Breeding was seasonal, starting in May, peaking in August, and finishing by the end of August. The species showed continuous production of successive broods. Laboratory observation showed that females with embryos near hatching had ovaries filled with vitellogenic oocytes ready for spawning. The reproductive output (effort) of each female (mean number of eggs: $552{\sim}1355$) was not high. The mean embryo volume, $0.078mm^3$, is relatively small, indicative of low energy allocation to each embryo. Recruitment of juveniles was closely linked to the breeding period, beginning in September.

• Journal of Aquaculture
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• v.20 no.4
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• pp.265-269
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• 2007

We studied the effects of temperature on the egg development and larvae of Takifugu pardalis. The larvae hatched 135-480 hr after fertilization in $13^{\circ}C-24^{\circ}C$ and 32 ppt. The higher the temperature the earlier the larvae hatch within $13^{\circ}C-24^{\circ}C$. The maximum hatching rate was made in $15^{\circ}C$ and 32 ppt. The higher the temperature the larger the newly hatched larvae. The larvae hatched in $24^{\circ}C$ were ca. 3.35 mm in total length. Occurrence of the deformed larvae was lower in $13^{\circ}C-18^{\circ}C$ regime and higher over $21^{\circ}C$ regime.

• Environmental Analysis Health and Toxicology
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• v.17 no.1
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• pp.1-6
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• 2002

Effects on nonylphenol (NP) treatment on early development of fertilized eggs and survival of larvae in olive flounder, Paralichthys olivaceus were investigated. Fertilized eggs and hatched larvae were exposed to aqueous solutions of NP at nominal concentrations of 50, 100, 150 and 200 $\mu\textrm{g}$/L. In the control I and II (methanol-carrier control) groups, the hatchability of fertilized eggs were 90.7$\pm$7.02 and 90.0$\pm$5.29％ (P <0.05), respectively. However, treatments of NP concentrations at 50, 100, 150 and 200 ug/L were reduced to 78.7$\pm$4.16, 46.0$\pm$9.17, 48.0$\pm$3.46 and 33.3$\pm$11.02% (P<0.05), respectively. The time to hatching of fertilized eggs was delayed in high-dose NP treatment groups rather than control groups. Fertilized eggs of NP immersed group could not hatch normally, and also vertebra of the larvae observed as abnormal shape. Cumulative mortality of hatched larvae after 26hr NP treatment was 38.3, 78.3, 88.3 and 100% in NP 50, 100, 150 and 200 ug/L treatment groups, respectively. Whereas, control I and II were 11.7, 16.7% (P<0.05). Hatched larvae showed most death at the embryonic development stage with abnormalities. These results suggest that NP treatment in fertilized eggs and larvae was inhibited as normally development for fertilized egg and growing of larvae.

• Korean Journal of Veterinary Research
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• v.56 no.3
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• pp.167-176
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• 2016

We investigated whether maternal antibodies (mAbs) elicited by dams immunized with recombinant vaccine candidates against avian pathogenic Escherichia coli (APEC) can passively confer protective immunity to chicks. In the present study, pBP244 plasmids carrying selected antigens of APEC were transformed into Salmonella Typhimurium JOL912, which was used as a vaccine candidate against APEC. The hens were immunized with the vaccine candidates using prime or booster doses. The levels of IgG and sIgA specific to the selected antigens increased significantly following prime immunization. To evaluate the persistence of passively transferred mAbs, the levels of IgY and IgA were determined in egg yolks and whites, respectively. The eggs from the immunized group showed consistently increased levels of IgY and IgA until week 16 post-laying (PL) and week 8 PL, respectively, relative to the control group. The presence of mAbs was observed in chicks that hatched from the hens, and titers of plasma IgY were consistently raised in those from the immunized hens by day 14 post-hatching. Further, chicks from the immunized hens were protected from challenge with a virulent APEC strain, whereas those from non-immunized hens showed acute mortality.

• Journal of Food Hygiene and Safety
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• v.14 no.1
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• pp.60-66
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• 1999

Diethylnitrosamine (DEN) is known as a potential hepatic carcinogen by single administration. This study was designed to measure the effects of DEN-induced cell damage on the triglyceride and cholesterol concentration in the liver, excluding dietary effects. Fertilized chicken eggs, 10 days before hatching, were randomly divided into three groups (n=20) and each egg was injected 10 ${mu}ell$ of corn oil (vehicle control), 5 $\mu\textrm{g}$ of DEN/10 ${mu}ell$ of DEN/10 ${mu}ell$ into yolk via air sac. After 48 hr and 96 hr incubation, the damage of the chick-embryo liver cell was investigated by electron microscopy and by measuring the concentration of lipid components (total cholesterol, free cholesterol, phospholipid and triglyceride). For eggs administered 10 $\mu\textrm{g}$ of DEN and incuvated 96 hr, in hepatocyte, the nucleus membrane was roughed, the size of nucleolus was apparently increased and euchromatin was accumulated. Mitochondria were condensed and cristae, located mitochondiral inner membrane, were obscured. Additionally, the leaves of triglyceride and cholesterol classes were significantly increased depend on the amount treated with 10 $\mu\textrm{g}$ DEN at 96 hr, but phospholipids component of cell membrane, were decreased with significance. As a conclusion, carcinogen induced hepatic lesion was correlated with the changes in lipid component of liver.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.2
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• pp.129-132
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• 2001

Biometabolic assessment was made in early and late embryonic stage (just before hatching) of one poly, one bi and their hybrids (DP, YPe, DP ${\times} Ype, and YPe ${\times} DP respectively ) of Bombyx mori to observe the racial differences. Protein and nucleic acid (RNA and DNA) concentrations were recorded to be significantly higher in bivoltine breed (YPe) and also in the hybrid than the polyvoltine (DP) strain in both the stages of embryonic development. The single egg weight of polyvoltine race was lower as compared to that of bivoltine and the hybrid studied. Age specific changes in all the biomolecules were evident where protein and RNA concentrations were elevated sharply in prehatched larvae while in case of DNA it was observed to be just reverse. The differences in protein, RNA and DNA composition between breeds and hybrids reflect the racial variations in biometabolic demands responsible for differential growth and development of the breeds and hybrids.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2006.10a
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• pp.98-102
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• 2006

We studied the behavior of black vultures breeding in Erdenesant, Mongolia through time budget observation. We observed a pair of black vulture for 115 days from April 30 to August 22, 2005, of which 15 days were before hatching and 100 days of brood rearing. The egg hatched on May $14^{th}$. Incubation was done by both a male and female vultures, but the period covered by the male vulture(56.82%) was longer than that by the female one(34.62%). In the early days of brood rearing, time spent by the female vulture at the nest took 54.9 % and it was 19.27% for the male. In the middle of brood rearing period, just inaction and preening were noticed, as they watched their chicks for a long time without sheltering chick under the parent's body. Late brood rearing period was characterized by less chick care and adults mostly stayed in the nest only when to feed the chicks. During breeding time, both the male and the female vulture fed only the chicks and did not give food to each other. During rearing period, the male vulture fed the chick more often than female.

• Environmental Analysis Health and Toxicology
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• v.24 no.1
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• pp.1-8
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• 2009

In this study, we obtained the fertilized eggs from goldfish(Carassius auratus) and observed normal developmental stage(from fertilized eggs to larvae) in non-exposed groups. Goldfish embryos at 3 h postfertilization(hpf) were statically exposed for 1 h to either dimethylsufoxide(DMSO, 0.1%, v/v) or TCDD($0.5{\mu}g/L$). Toxicity and morphological changes were characterized from 3 to 120 h postfertilization(hpf). Egg mortality($0{\sim}48$ hpf) and hatching ratio($72{\sim}83$ hpf) in TCDD-exposed group were significantly different from control groups. However, pericardial edema was first observed at 72 hpf, followed by the onset of yolk sac edema and mortality. In addition, goldfish embryos-larvae exposed to TCDD significantly increased TCDD-related gene such as CYP1A($24{\sim}72$ hpf) and AhR2(72 hpf). This is the first study about in-depth characterization of TCDD-induced developmental toxicity in goldfish(Carassius auratus).