• Reproductive and Developmental Biology
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• v.31 no.2
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• pp.61-69
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• 2007

This study was designed to evaluate effects of BSA, PVA, gonadotropins and follicle shell during IVM of porcine oocytes and subsequent development to the blastocyst stage after IVF. Cumulus oocyte complexes (COCs) were cultured in TCM-199 media containing 4 mg/ml BSA and 1 mg/ml PVA during IVM for 44 hr. To compare the effect of gonadotropins on oocyte maturation, COCs were cultured with FSH+LH, FSH, LH and FSH-LH-free media during IVM. respectively. Also, different number of follicle shells (0, 2, 4 and 6) was used to examine whether the presence of follicle shell in culture medium affects oocyte maturation. The percentages of fertilization and blastocyst formation, respectively, were higher in the medium containing the PVA (49.0 and 17.9%) than those containing the BSA (40.0 and 12.2%). Significantly higher rates of Mil oocytes were in the presence of FSH+LH and FSH (88.6 and 85.1 %) compared to other treatments (64.0 and 53.4% at LH and FSH-LH-free media). Co-culture with inverted follicle shells in 2 ml maturation medium enhanced the developmental competence of porcine oocytes. In conclusion, PVA could be used as a macromolecules instead of BSA, and FSH and follicle shell played important roles in maturation of porcine oocytes.

• Journal of Aquaculture
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• v.21 no.4
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• pp.252-258
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• 2008

Gonadal development and reproductive cycle of the ark shell Scarpharca subcrenata were investigated by histological observations. Samples were collected monthly from March 2007 to February 2008 in the Yeoja Bay, Yeosu, Jeollanam-do, Korea. S. subcrenata was dioecious. The gonads consist of a number of oogenic follicle and acinus. Monthly changes in the gonad index reached a maximum in June and a minimum in September. Monthly changes in the condition index reached a maximum in April and a minimum in September. The reproductive cycle of this species can be divided into five successive stages: early active stage (January to April), late active stage (March to June), ripe stage (May to August), spent stage (July to September) and recovery and resting stage (September to March). The main spawning of S. subcrenata occurred in July and August in Yeoja Bay. The sex ratio of female to male was not significantly different from 1:1.

• Journal of Sericultural and Entomological Science
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• v.30 no.2
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• pp.88-95
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• 1988

The structure ki mutant chorion is described by the ultrastructural level with the scanning electron microscope. The micropyle on the anterior, posterior, leteral and dorsal side region surface patterns do not so much differ from ki mutant and normal strains. The surface structure of ventral side of ki mutant, which is the presumptive embryonic region in oocytes, were netted part corresponding to the boundary of follicle cells that is similar to lateral side structure of egg-shell. The eggshell thickness of ventral side on the ki mutant is mostly thicker. However, the structure of transverse section of normal and ki mutant egg-shell are composed of the outer, middle and inner layers. The ki not effects the formation of the lamellar layer in the egg-shell. It is observed that the characteristic structure in ki mutant egg chorion may be attributed to a areal specificity of epithelium in ventral side of egg-shell formation, and it affects the process of the accumulation of secreted chorionic material and the egg-shell architecture.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.82-93
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• 1998

Monthly changes of the gonad follicle index (GFI), reproductive cycle, egg-diameter composition, first sexual maturity of the Pacific oyster, Crassostrea gigas, were studied based on the samples which have been collected from the intertidal zone of Poryong west coast of Korea, from January to December, 1996. C. gigas, is dioecious, while a few individuals are alternatively hermaphroditic. Monthly variation of gonad follicle index (GFI) used for determination of spawning period, coincided with the reproductive cycle. GFI increased from April when seawater temperatures gradually increased and reached the maximum in May. And then, GFI sharply decreased from June to September due to spawning. Reproductive cycle of this species can be divided into five successive stages: in females, early active stage (March to April), late active stage (April to May), ripe stage (May to August), partially spawned stage (June to September) and spent/inactive stage (September to February); in males, early active stage (February to March), late active stage (April to May), ripe stage (May to September), partially spawned stage (June to September) and spent/ inactive stage (September to February). The diameter of fully mature eggs are approximately 50um. Spawning occurred from June to September, and two spawning peaks were observed in June and August when the seawater temperature was above $20^{\circ}C$. Percentages of the first sexual maturity of males of 20.1-25.0 mm in shell height were over $50\%$, while those of females of 25.1-30.0 mm in shell height were over $50\%$. All the males of > 30.1 mm and all the females of ^gt; 35.1 mm completed their first sexual maturity. The results suggest that C. gigas has a protandry phenomenon. Sex ratios of 919 oysters observed were 453 females $(49.29\%)$, 429 males $(46.68\%)$, 16 hermaphrodites $(1.74\%)$, and 21 indeterminate individuals $(2.29\%)$. In age class I, sex ratio of males were $64.00\%$, thus, a higher percentage than that of females. It was noted that $64.00\%$ of the young males (age class I) were more functional than females in age class I, but 2-3 year-old oysters showed higher percentage of females. Percentages of hemaphrodites in 2-3 year classes were relatively higher than those in other year classes. Histological pattern of hermaphrodites can be divided into two types: Type I (hermaphrodite having a number of newly formed developing oocytes on the oogenic tissues within a degenerating spermatogenic follicle after discharge of numerous spermatozoa) and Type II (hermaphrodite having two separate follicles in the same gonad).

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.1049-1056
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• 2010

This study was conducted to investigate the effects of dietary glutamine (Gln) on the productive performance and egg quality of laying hens. A total of four hundred Lingnan Yellow laying hens aged 34 weeks were randomly assigned into four groups (100 laying hens/group), and fed, respectively, with diets supplemented with 0% (control group), 0.2%, 0.4%, and 0.8% Gln during the 6-week feeding period. The results were as follows. First, the productivity of laying hens fed with 0.8% Gln in diet was significantly increased (p<0.05); however, the egg quality (egg weight, yolk weight, shell weight, egg shape index, shell thickness, shell density, shell breaking strength, yolk color, yolk index, and Haugh unit) was not affected compared with that of the control group (p>0.05). Second, luteinizing hormone (LH) (p<0.01), follicle stimulating hormone (FSH) (p<0.01), triiodothyronine ($T_3$), and tetraiodothyronine ($T_4$) contents (p<0.05) in blood of laying hens fed with 0.8% Gln in diets were also significantly improved, and greater improvement in the duodenum and oviduct structure was observed in that treatment group. This study indicated for the first time that diets with 0.8% Gln were able to increase the productive performance of laying hens through stimulating hormone secretion and better development of both the duodenum and oviduct structure in laying hens.

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.261-271
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• 2011

The gametogenic cycle, the spawning season and the biological minimum sizes in female and male Protothaca (Notochione) jedoensis were investigated by quantitative statistical analysis. In females, monthly changes in the percents of the follicle areas to the ovarian tissue areas and the percents of the oocyte areas to the ovarian tissue areas increased in February and reached the maximum in April, and then gradually decreased from May to July, with the spawning peak between June and July. In males, monthly changes in the percents of the testicular tissue areas to total tissue areas and the percents of the spermatogenic stage areas to the testicular tissue areas increased in February and reached the maximum in April, and then showed a rapid decrease from May to July. From these data, it is apparent that the number of spawning seasons in female and male P. (N.) jedoensis occurred once a year, from May to July. Therefore, P. (N.) jedoensis in both sexes showed a unimodal gametogenic cycle during the year. Compared the gametogenic cycle by quantitative statistical analysis in 2007 with the previous qualitative results of this species, the results of the gametogenic cycle calculated by quantitative statistical analysis showed some differentiations in the spawning seasons evaluated by the gonad index by qualitative histological analysis. The intervals of the beginning of two spawning seasons showed one month between the results of quantitative and qualitative analyses. The biological minimum sizes (considering to 50% of group sexual maturity) in female and male clams by quantitative analysis of this species are 32.01 mm in shell length in females and 30.58 mm in males, respectively. According to the mean shell length fitted to von Bertalanffy's equation, 30.58 and 32.01 mm in shell length were considered to be two years old. Therefore, we assume that both sexes of this population begin reproduction from two years of age.

• Animal Bioscience
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• v.37 no.1
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• pp.95-104
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• 2024

Objective: In the present study, we aimed to investigate the effects of enzymolysis fermentation of Chinese herbal medicines (CHMs) on egg production performance, egg quality, lipid metabolism, serum reproductive hormone levels, and the mRNA expression of the ovarian hormone receptor of laying hens in the late-laying stage. Methods: A total of 360 Hy-Line Brown laying hens (age, 390 days) were randomly categorized into four groups. Hens in the control (C) group were fed a basic diet devoid of CHMs, the crushed CHM (CT), fermented CHM (FC), and enzymatically fermented CHM (EFT) groups received diets containing 2% crushed CHM, 2% fermented CHM, and 2% enzymatically fermented CHM, respectively. Results: Compared with crushed CHM, the acid detergent fiber, total flavonoids, and total saponins contents of fermented CHM showed improvement (p<0.05); furthermore, the neutral and acid detergent fiber, total flavonoids, and total saponins contents of enzymatically fermented CHM improved (p<0.05). At 5 to 8 weeks, hens in the FC and EFT groups showed increased laying rates, haugh unit, albumin height, yolk color, shell thickness, and shell strength compared with those in the C group (p<0.05). Compared with the FC group, the laying rate, albumin height, and Shell thickness in the EFT group was increased (p<0.05). Compared with the C, CT, and FC groups, the EFT group showed reduced serum total cholesterol and increased serum luteinizing hormone levels and mRNA expressions of follicle stimulating hormone receptor and luteinizing hormone receptor (p<0.05). Conclusion: These results indicated that the ETF group improved the laying rate and egg quality and regulated the lipid metabolism in aged hens. The mechanism underlying this effect was likely related to cell wall degradation of CHM and increased serum levels of luteinizing hormone and mRNA expression of the ovarian hormone receptor.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.629-636
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• 1999

Gonadal development, gametogenesis, reproductive cycle, egg-diameter and composition, condition factor, and the first sexual maturity of the clam, Potamocorbula amurensis were investigated by histological observation. Samples were collected monthly from the tidal flat of Moonpo, Puan-gun, Chollabuk-do, west coast of Korea from November 1996 to October 1997. P. amurensis is dioecious and oviparous. The gonads were composed of a number of gametogenic follicles. The oogonia and fully ripe oocytes were $9\~12\mu$m and $50\~60\mu$m in diameter, respectively. Each of the spermatogenic follicle formed stratified layers composed of spermatogonia, spermatocytes spermatids, and spermatozoa in groups on the follicular wall. The reproductive cycle of P. amurensis could be classified into five successive stages: early active, late active, ripe, partially spawned, and recovery. Spawning occurred twice a year from May to July and from September to October, the main spawning seasons also appeared twice a year between May and June, and in October when the water temperatures reached above $18^{\circ}C$. The monthly changes in the condition factor were closely related with the reproductive cycle. Minimum size for the sexual maturation of female and male were 8.1 mm in shell length. There were two patterns for the gametogenesis: 1. After spawning, the undischarged ripe oocytes and spermatozoa in the follicles were degenerated and absorbed, but in part, the existing follicles were not contracted significantly and then they took part in new gametogenesis within one or two months (especially, in summer). 2. After spawning, each follicle was contracted, thereafter gametogenesis again occurred in newly formed follicles.