• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.281-289
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• 2022

The effect of five different constant temperatures (18, 21, 24, 27, and 30±1℃) and a photoperiod of 14 : 10 (L :D) h on the reproduction parameters of Spodoptera frugiperda was studied. The longevity of adult female S. frugiperda decreased with increasing temperature (22.4 days at 21℃ and 13.9 days at 30℃) but not at 18℃. The pre-oviposition period and oviposition period was the shortest at 30℃ compared to the other temperatures. The total fecundity egg count was 887.4, 1,246.4, 1,348.9, 1,154.9, and 1,034.2 at 18, 21, 24, 27 and 30℃, respectively, during its life span. The survival rate of female S. frugiperda decreased rapidly after 13 days at 18℃, after 14 days at 21℃, after 15 days at 27℃, and after 9 days at 24℃, and 30℃. On the third day after the start of oviposition, 50% of the total fecundity was accomplished. In corn fields at less than the 10-leaf stage, the distribution of S. frugiperda egg masses was observed in the middle and lower plant regions, corresponding to 46.8% and 41.4% of the total egg masses, respectively. Egg masses were mostly found on the underside of the leaf blade (abaxial) of corn(66.7%). After releasing S. frugiperda adults on May 12, May 17, May 25, and May 30, the number of eggs per egg mass was 89.9, 88.5, 126.6, and 127.9, respectively. Egg masses of the subsequent generations of S. frugiperda were observed from late June, and the number of eggs per egg mass was 155.8 in late June, 270.7 in early July, and 303.5 in mid-July.

• Journal of the korean veterinary medical association
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• v.25 no.5
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• pp.282-291
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• 1989

Incidence of infectious bronchitis virus(IBV) infection in vaccinated breeder chickens was investigated by hemagglutination inhibition(HI)test for IBV using Mass 41 antigen. In the breeder chickens with the reduced egg production. chalky deposit. wrinkled

• Korean Journal of Poultry Science
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• v.30 no.3
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• pp.183-189
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• 2003

This study was carried out to evaluate effect of dietary green tea by-products (GTB) on laying performance and quality of eggs in hens. A total of 96 laying hens (22-week-old) "Tetran Brown" were allotted to four dietary treatments, which containing 0, 2, 4 and 6% green tea-by products. The results showed that the egg production increased (P＜0.05) in layers fed diets containing 4% or 6% green tea-by products compared to the layers fed control no GTB. Egg weight and egg mass in layers fed diets containing 2% green tea by-products significantly decreased compared to those in the other groups (P<0.05). The feed intake was lower in layers fed diets containing 2% and 6% green tea by-products. The feed conversion ratio was lower (P<0.05) in layers fed diets containing 4% or 6% green tea by-product supplementation respectively. The egg shell thickness was no significantly different between layers fed the control and green tea by-product diets (P>0.05). The egg yolk cholesterol tended to decrease when layers fed diets containing green tea by-products, although the differences were not significant (P＞0.05). The linolenic and docosahexaenoic (DHA) acid contents in egg yolk significantly increased in layers fed diets containing different levels green tea by-products compared to those fed control diet (P<0.05). These results suggest that inclusion of green tea by-products in layer diets is suitable for hens without negative effects on egg composition.

• The Korean Journal of Ecology
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• v.22 no.5
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• pp.299-303
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• 1999

Studies were conducted in Mt. Namsan, Seoul, during the summer of 1997 and 1998 using racemic disparlure to determine seasonal occurrence and circadian activity in male gypsy moth, and size of egg mass and wing length of male moth. Male gypsy moths occurred from middle part of July until middle part of August and peaked in late part of July. Circadian activity of male moths initiated from 12: 00h and continued until 21: 00h, and the peak time was between 14: 00h and 17: 00h. Mean number of moths captured per trap in 1997 was larger than that in 1998, however, eggs per mass, egg size and wing length were not significantly different between the two years, 1997 and 1998.

• Mass Spectrometry Letters
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• v.12 no.1
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• pp.11-15
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• 2021

Nitarsone is an organoarsenic antiprotozoal drug widely used to treat blackhead disease in turkeys and chickens. However, since its biological conversion into inorganic arsenic, a carcinogen was known, its residue in foods should be regulated. Thus, here, a novel method to determine residual nitarsone in various food commodities (pork, milk, egg, halibut, eel, and shrimp) using QuEChERS and LC-MRM was developed. The developed method was successfully validated through specificity, linearity (coefficient of determination, at least 0.991), recovery (R, 63.6 - 85.6%), precision (the relative standard deviation of R, 0.5 - 10.6%), and sensitivity (the lower limit of quantitation, 5 ppb) by following the Ministry of food and drug safety (MFDS) guidelines. The present method is the first mean to quantitate nitarsone using LC-MRM, and it was designed to be conveniently merged into a new method to quantitate multiple veterinary drugs for the positive list system (PLS). Therefore, the present method could contribute to fortify the food safety system in South Korea.

• Journal of the Korean Dietetic Association
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• v.8 no.2
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• pp.199-205
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• 2002

In this study, we found a new food additive as an natural herbal extracts against lipid digestion enzymes for the regulation of fatty acid absorption and weight control. The Water extracts of Platycodon grandiflorum and Solanum melongena. inhibited lipase activity and decresed serum total cholesterol and triglyceride concentration in mouse fed lipid emulsion. Twenty three volunteers were subjected to the intake of the herbal extracts plus the egg yolk IgY that inhibit carbohydrate digestion enzymes in gut for 50 days. In average, the treated subjects appeared to lose 1.96 kg of body weight and 3.4 kg of body fat mass during the treated period. Furthermore, Panniculus adiposus and breech size were significantly decreased during the experimental period. Above results suggested that the administration of the dietary additives composed of natural herbal extract and egg yolk IgY improve the obesity by the decrement of body weight and body fat mass.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.4
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• pp.234-242
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• 2009

To develop the artificial spawning seaweeds of the sandfish, Arctoscopus japonicus, the effects by the material type of artificial spawning seaweeds were investigated at Dongsan port in Gangwon-do from December 2006 to March 2007. Sargassum fulvellum, S. horneri, rope and net were used as materials for artificial spawning seaweeds, and the most effective thing among them was S. fulvellum. A. japonicus began to attach the egg mass to artificial spawning seaweeds when sea temperature dropped below 10${^{\circ}C}$ in December, spawned heavily when it was around 8${^{\circ}C}$ in January, and completed the behavior when it started to increase over 10${^{\circ}C}$ in February. The hatching period of eggs was estimated to be about 60 days. The middle position in artificial spawning seaweed had the highest number of egg masses and the diameter of the egg mass ranged from 25mm to 62mm. Based on the result for the effects, the artificial spawning seaweeds of A. japonicus were developed and it is possible to use them to form seaweed forests or spawning grounds of other species.

• Korean Journal of Ichthyology
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• v.29 no.4
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• pp.252-257
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• 2017

The oogenesis of the Microphysogobio yaluensis was investigated using light microscopy. Various developmental oocytes appeared in the ovary of the M. yaluensis. The oogenesis is largely divided into four stages: nuclear-chromatin stage, peri-nucleoli stage, vitellogenesis (yolk vesicle and yolk granule stages), and mature stage. The nuclear-chromatin is distributed in a large germinal vesicle as threads. The peri-nucleoli stage has many acidic nucleoli lining at the inner side of the nuclear membrane and an egg envelope just weakly starts. As the oogenesis gradually proceeds, they change to the vitellogenesis stage. The oocyte become to drastically increase and the marginal area of the ooplasm is covered with many vacuoles showing no negative reactions with hematoxylin and eosin staining, called the yolk vesicle stage. Many yolk vesicles-owned oocyte largely increase and as the development continues, its ooplasm is changed from the yolk vesicles to the yolk granules of eosinophilic. At the mature stage, lots of granules merged into a big yolk mass, acidophilic. Even at the mature stage, the egg envelope was still thin between the ooplasm and the follicular layer of the oocyte.

• 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.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.357-363
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• 2017

Hatchability of eggs and rate of weight reduction in pruned twigs with egg-mass of R. shantungensis were investigated in blueberry and peach orchards from December to March. Hatchability of R. shantungensis eggs were 52.8~68.4% on normal twigs in the field. However, the rate of hatchability dropped to less than 1% after pruning. Moisture content of twigs after pruning blueberry and peach were 9.8~20.9% and 7.5~13.8%, respectively. This result revealed that the hatchability of R. shantungensis eggs might be very low or nil, because the eggs dried up after pruning of the twigs with egg-masses of R. shantungensis.