• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.853-859
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• 2006

This study was carried out to investigate the effect of egg shell calcium salt types and egg shell membrane on calcium metabolism in rats. Sprague-Dawley male rats, 4 weeks of age, were fed on free-calcium diets for 2 weeks after adjustment period. Rats weighing approximately $247{\pm}2.3g$ were divided into 6 groups and were fed on the experimental diets containing 0.2% calcium for 4 weeks. Experimental groups were as follows; {ES(M+)} (egg shell powder diet with egg shell membrane), {ES(M-)} (egg shell powder diet without egg shell membrane), {AC(M+)} (egg shell calcium acetate diet with egg shell membrance), {AC(M-)} (egg shell calcium acetate diet without eg shell membrane), {GC(M+)} (egg shell calcium glucuronate diet with egg shell membrane) and {GC(M-)} (egg shell calcium glucuronate diet without egg shell membrane). Bone length of femur was significantly different by the types (p<0.05) of egg shell calcium salts. Bone mineral density of femur showed the highest level in AC(M-) group. Calcium content of femur and calcium absorption rate were higher in egg shell calcium salt groups than in eg shell powder groups. Calcium absorption rate and retention were significantly different (p<0.05) among the types of eg shell calcium salts and were higher in the AC(M-) group than in the other groups. Alkaline phosphatase activity, parathyroid hormone and osteocalcin levels of serum showed no significant difference among the experimental groups. From the above results, it is concluded that bioavailability of calcium is higher in groups of egg shell calcium salts compared to those in egg shell powder, even though egg shell membrane has no effect on calcium metabolism. Thus, these findings suggest the possibility of using egg shell calcium salts as a functional food material related to calcium metabolism.

• The Korean Journal of Malacology
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• v.23 no.2
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• pp.209-216
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• 2007

The ovarian structure and ultrastructural changes in germ cells during oogenesis of the spiny top shell, Batillus cornutus, have been investigated by light and electron microscopic observations. Specimens of the spiny top shell were collected from the subtidal zone of Wando, south coast of Korea. Spiny top shell was dioecious. The ovary was located on the surface of the hepatopancreas in the spiral posterior region. The ovary had greenish color in the gonadal mature season. The ovary comprised many ovarian lobules, and the ovarian lobule consisted of connective mesenchymal tissue and epithelial cells. Oogonium had a large nucleus with nucleolus of high electron density. In previtellogenic oocyte, small yolk granules of low electron density were scattered in the cytoplasm. Oocytes in the initial vitellogenic stage were connected with the ovarian lobule by egg stalk. The result of TEM observations showed that initial vitellogenic oocyte contained well-developed Golgi complex, endoplasmic reticula, tubular mitochondria and numerous yolk granules of various electron densities and sizes. The electron density, size and quantity of yolk granules which were distributed in the active vitellogenic oocyte were increased compared to the previous stage. Thickness of egg envelope in the late active vitellogenic oocyte was approximately 4.4 $[\mu}m$. Cytoplasm of ripe oocyte was filled with proteid yolk globules of high electron density and lipid yolk globules of low electron density. In this stage, the thickness of egg envelope was approximately 6.5 ${\mu}m$.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.65-70
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• 2000

Field collections were made from six gypsy moth (Lymantria dispar L.) Populations in Kyonggy and Cheju areas during the period 1987∼1997. Characteristics of gypsy moth populations at different phases were examined in terms of egg mass density, relative larval density, plant damage, and fecundity. Males captured in pheromone trap were recorded, and we examined if there was a relationship between numbers captured and the population density during the following generation. Egg mass density was closely related with larval density, and furthermore these densities were correlated with the level of plant damage, indicating that larval dispersion was limited in oviposition areas. The gypsy moth population cycle was short in Korea with the period from population development to innocuous level usually lasting 2∼3 years. Male caught by pheromone trap (mean number of males caught per trap per day in peak emergence period) was positively correlated with egg mass densities in the following season (r²=0.93). A low fecundity was detected from outbreak populations which accompanied defoliation. Fecundity of gypsy moth ranged from 538 to 601 at other phases.

• Korean journal of applied entomology
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• v.37 no.2
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• pp.193-198
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• 1998

Experiments were conducted to investigate the population fluctuation, developmental periods, fecundity, hatching rate and demage of Citrus red mite (Panonychus citri M.) on Yuzu trees (citrus junos T.) from 1996 to 1997. Citrus red mite occurred from May to November and made two peaks. The first peak was in July to August and the secondary peak was in October. Density of the second peak was higher (9.5 miteslleaf) than that of the first peak. In the constitution rate of each developmental stage of citrus red mite on Yuzu leaves, egg stage occupied 85%. At the four constant temperature (15, 20, 25, 30 + 1$^{\circ}$C, RH 60 + lo%, 14L- IOD) conditions, the developmental period from egg to adult was 41 .l, 15.5, 11.0 and 9.4 days ; Mean longevity of adult was 23.3, 8.3, 6.3, and 6.1 days; Mean number of egg laid per female per day was 1.6, 3.2, 4.5, 4.0 eggs; Mean hatching rate was 66.6, 85.7, 90.7 and 94.7% at above temperature, respectively. When sprayed acaricide at different density of Citrus red mite, the growth of young Yuzu tree were better at low density. Defoliation rate during winter was 13.5, 20.6, 53.1, 72.6% at 4 control density 1 , 3, 6 mites per leaf and uncontrolled (10 ( ). When every time spray acaricide under 3 mites per leaf, defoliation rate during winter suppressed above 50% compare to uncontrol 72.6%.

• Korean Journal of Poultry Science
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• v.21 no.2
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• pp.119-131
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• 1994

The physiological functions of drinking water in chicken were reviewed. The effects of ambient temperature, humidity, wind velocity, egg productivity, feed form, nutrients density, and breed types on the water consumption of chicken were summarized and discussed. Some guidelines for management of drinking water in commercial poultry farms were also suggested.

• Applied Microscopy
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• v.29 no.3
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• pp.343-351
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• 1999

The structures of the fertilized egg envelope from three species, three-spot gourami (Trichogaster trichopterus), pearl gourami (Trichogaster leeri) and marble gourami (Trichogaster trichopterus trichopterus) belong to Belontiidae were observed, utilizing light, scanning and transmission electron microscopes. In all three species, the fertilized eggs were the colorless, transparent, spherical, adhesive and pelagic type. A large oil droplet was located in vitelline membrane of the fertilized egg. The egg envelopes have a single micropyle, which is thought to the pathway of sperm in the area of the animal pole. Specially, the micropyle of three-spot gourami was similar to that of marble gourami which is subspecies of three-spot gourami. An outer surface of the fertilized egg envelope was arranged by grooves in all three species. The fertilized egg envelopes consists of two distinct layers; an adhesive outer layer and an inner layer with high electron density. In conclusion, the morphological similarity of the fertilized egg, micropyle, outer surface and transverse section of the fertilized e9g envelope seems to be an indication of the Belontiidae.

• Korean journal of applied entomology
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• v.32 no.1
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• pp.61-67
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• 1993

Experiments were conducted to study the functional response of Amblyseius longispinosus Evans to egg densities (10-80) of Tetranychus urtica Koch under different egg distributions (clumped & uniform) and arena sizes (3, 9 & 16 $cm^2$). The searching success of A. longispinosus was affected by the spatial distribution and density of the prey but not by the arena size. there was a highly significant negative correlation (r=-0.85; p=0.0001) between predation amount and distances between preys. The predation response showed a type III functional response. The random predator equation satisfactorily described A. longispinosus predation. The search rate ranged from 0.1030 to 0.1504 under distribution of the prey while it ranged from 0.0546 to 0.276 under uniform distribution.

• Korean journal of applied entomology
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• v.33 no.2
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• pp.114-121
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• 1994

Population densities of intermediate nymphs and egg saw of Matsucoccus thunbergianae, a major insect pest of Pinus thunbergiona in southern coastal area of Korean peninsula, were est~mated. Tree samples of ca. 10cm D.B.H. were collected from old infestation area and newly invaded area. The numben of plimaly branches per tree were not significantly different by the locality, but those of secondaly and smaller branches were smaller in old infestation area The numbers of intermediate nymphs per tree in old infestation area and in newly invaded area were 10.8 and 13.1 times more than those on the trunk, respectively Approximately between 4, 200 and 208, 500 nymphs per tree were estimated. Men secondaw and smaller bmnch samples collected from the basal part of middle crown height, or from the central or the basal part of lower crown height, the number of samples required for the emr range of 20% were 21 and 11 far 10-20cm and 20-3 crn long branches, respectively. Approx~mately 63.6% of egg sacs of the whole tree were on the trunk. The node/intemode bearing the largest branch had the highest egg sac density; including that, four adjacent nodes/intemodes had ca. 37% of egg saw on the trunk.

• Parasites, Hosts and Diseases
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• v.48 no.2
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• pp.121-126
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• 2010

To know the prevalence of Enterobius vermicularis infection and what are the most important risk factors, we evaluated the incidence and risk factors of enterobiasis among children attended in kindergartens in Busan metropolitan city, Republic of Korea. A total of 1,674 children from 21 kindergartens in 11 of 16 autonomous districts of Busan were evaluated for E. vermicularis infection by the cellotape anal swab technique. The overall egg-positive rate for E. vermicularis was 10.7% (179/1,674), and the prevalence of enterobiasis in each kindergarten ranged between 0% and 32.4%. There was an increasing tendency of the egg positive rate according to the population density; the higher the population density communities had, the higher egg-positive rate for E. vermicularis was detected (P = 0.001). Among personal hygiene factors involving children, thumb-sucking (P = 0.036) and fingernail-trimming (P = 0.024) were highly associated with enterobiasis. In addition, taking anthelmintic medications against E. vermicularis infection was strongly associated with enterobiasis (P = 0.014). Moreover, parents' knowledge of enterobiasis was correlated significantly with the incidence of enterobiasis of their children (P = 0.006). In conclusion, we need to consider not only personal hygiene but also parents' knowledge about enterobiasis as a factor in order to develop new strategies for elimination or to complete reduction of enterobiasis in Korea.

• Applied Microscopy
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• v.25 no.3
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• pp.63-74
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• 1995

The development of pale chub oocyte from the immature oogonium to mature oocyte was investigated by light and electron microscope. The cytoplasm of pale chub oogonia was acidic and many vesicles were located at inner side of nuclear membrane. In primary oocytes, yolk vesicles were distributed in cytoplasm. Also, fibrous materials and protuberances were distributed on the surface of zona radiata. The nucleus of secondary oocyte was enlarged and yolk vesicles in cytoplasm migrated to zona radiata. In early egg, yolk mass are formed and yolk vesicles were located at inner side of zona radiata. Three-layered zona radiata was about $3{\mu}m$ in thickness. The three layers were an outer fibrous material layer, a middle nurse cell layer in which microvilli of early egg cytoplasm contact with processes of nurse cells, and an inner layer with high electron density. In mature egg, euchromatin and a germinal vesicle were developed, mitochondria, free ribosomes, and yolk mass were distributed in cytoplasm. But, yolk vesicles were disappeared. Specially, zona radiata of matured eggs were better thin than the one of immature eggs In conclusion, it is summerized that the oogenesis of pale chub were the increase of cell size, the formation and accumulation of yolk, the decrease in nucleat electron density, changes of zona radiata, and the development of microvilli.