• Korean Journal of Animal Reproduction
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• v.24 no.1
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• pp.77-82
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• 2000

This study was conducted to establish the methods of ultrasound-guided transvaginal retrieval of oocytes (ovum pick-up) in Korean native, Hanwoo Heifers. To obtain the basic data about Hanwoo, the size of ovaries in luteal and follicular phases were measured and the number of follicles in ovaries during the estrus cycle was counted by using ultrasound. And to determine the effective anesthetic to Hanwoo, various mixture of anesthetic compounds, Rompun(equation omitted), lidocaine, Monzal(equation omitted), and Domosedan(equation omitted), were treated. The size of Hanwoo ovaries were not significant differently between luteal and follicular phases. The number of medium and small follicles were peak on day 3 and 12 of the estrous cycle, and this result suggested that Hanwoo has 2 follicular growth waves per estrus cycle. The most effective anesthetic method was intramuscular injection of a.3m! Rompun(equation omitted), epidural injection of 5$m\ell$ lidocaine and sprayed cervix by 2$m\ell$ lidocaine.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.3
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• pp.245-257
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• 2020

Behavioral response to a diel photoperiodicity (500 lx for 16 h, 5 lx for 4 h and < 0.5 lx for 4 h) and phototactic characteristics in dark conditions were examined with Siberian sturgeon Acipenser baerii (Chondrostei, Actinopterygii) prelarvae. Siberian sturgeon prelarvae represented both qualitative and quantitative changes in their behavioral patterns according to different light intensities in a diel photoperiodicity. Under daylight conditions (500 lx), prelarvae displayed saltatory changes of behavioral features with ages (Day 0-Day 9) in a general order of swimming-up/drifting, swimming in the upper water column, benthic swimming with rheotaxis, schooling and post-schooling behavior. Compared to daylight conditions, prelarvae tended to show more benthic performances and quantitative reductions of schooling and post-schooling behaviors under dimlight conditions (5 lx). Under dark conditions (< 0.5 lx), prelarvae exhibited a fairly uniform behavioral pattern characterized by the benthic swimming across the bottom of the tank. From phototaxis tests under dark conditions, navigational responses of prelarvae to a spotlight illumination were quantitatively changed as their ages increased. The phototactic responses reached the peak on Day 2, continued until Day 4, and then gradually decreased until Day 8. A partial recovery of positive phototaxis was observed on Day 9. Data from this study suggest that the diel light cycle as well as the light intensity of each interval in the cycle should be considered as important components of a practical guide for evaluating fitness and developmental states of artificially propagated Siberian sturgeon prelarvae.

• Development and Reproduction
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• v.17 no.2
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• pp.87-97
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• 2013

The seminiferous epithelium cycle and developmental stages of spermatids in Clethrionomys rufocanus were observed under a light microscope. The seminiferous epithelium cycle was divided into 8 stages. Type Ad spermatogonia appeared through all stages. Type Ap, In, and B spermatogonia appeared in stages I, II, III, and IV. In the first meiosis prophase, the leptotene spermatocytes appeared from stage V, the zygotene spermatocytes in stages I, VI, VII, VIII, the pachytene spermatocytes from stages II to VI, the diplotene spermatocytes in stage VII. The meiotic figures and interkinesis spermatocytes were observed in stage VIII. Developing spermatids were subdivided into 10 steps, based on the morphological characteristics such as the acrosome formation changes in spermatozoa, nucleus, cytoplasm, and spermiation changes. The C. rufocanus spermatocytogenesis and spermiogenesis results displayed similar results with Apodemus agrarius coreae and A. speciosus peninsulae. Considering all the results, the spermatogenesis may be useful information to analyze the differentiation of spermatogenic cells and the breeding season.

• Korean Journal of Animal Reproduction
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• v.22 no.2
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• pp.153-161
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• 1998

This study was conducted to examine the viability of nuclear transfer bovine embryos following embryo transfer. Donor embryos were treated with nocodazole to arrest their cell-cycle-stage at mitotic(M) phase. After releasing from nocodazole blastomeres were separated and transferred into the enucleated oocytes(BC), or cultured in medium with aphidicolin. Freshly cleaved blastomeres within 1.5h after cleavage(AC) and non-cleaved ones up to 3h after releasing from nocodazole(NC) were transferred into the enucleated oocytes. Blastocysts derived from nuclear transfer were transferred to Day 7~8 recipient cows. Some blastocysts were vitrified and thawed before embryo transfer. Developmental rates to the blastocyst stage were higher in AC(18.1%, P<0.05) than BC(8.6%) and NC(5.1%). Blastocyst development slightly enhanced with aphidicolin(1~2$\mu\textrm{g}$/ml) treatment(16.9~22.6%) compared to non treated control(11.1%). Survival rate fo vitrified nuclear transfer embryos after thawing was 75%(24/32). Twnety-three vitrified nuclear transfer embryos and 3 fresh ones were transferred to 23 recipients, 6 heads were pregnant and 1 male calf(24 kg) was born from a recipient cow recevied one vitrifiedthawed nuclear transfer embryo at 277 days after embryo transfer. This result suggests that the nuclear transfer embryos can developed to term after vitrification andembryo transfer.

• Animal cells and systems
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• v.16 no.2
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• pp.135-144
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• 2012

$Dendronephthya$ $castanea$ Utinomi, 1952 is a member of the family Nephtheidae, and dominates shallow waters adjacent to the southern part of Jejudo Island, Korea. This species is a gonochoric internal brooder with a sex ratio of 1:1, and releases planulae around the time of the full and new moon from July to September, when the seawater temperature peaks. The gametogenic cycle is annual, and oogenesis (12 months) is longer than spermatogenesis (4-5 months). No difference in reproductive features including sexuality, sex ratio, gametogenesis and gametogenic cycles was found between the sympatric species $D.$ $castanea$ and $D.$ $gigantea$, and there was no temporal reproductive isolation. Investigation of the morphological taxonomy and molecular biology of these species indicates that they have very similar or identical traits, suggesting an absence of speciation and a need for taxonomic reclassification.

• Animal Bioscience
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• v.35 no.11
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• pp.1744-1751
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• 2022

Objective: The present study aimed to investigate the effect of xylo-oligosaccharides (XOS) administration on egg production, reproductive hormones, serum lipids and adipokines of hens at the late cycle of reproduction. Methods: Four treatments included control (basal diet) and XOS addition at 2.0 (XOS-2), 4.0 (XOS-4), or 6.0 (XOS-6) g/kg of diet using 288 commercial Hy-Line brown hens from 73 to 84 wk of age. Egg production, body fat deposition, reproductive tract and hormones, lipid metabolism and adipokines were determined. Results: At 84 wk, compared to the control, XOS supplementation at the three doses increased (p<0.001) egg-laying rates by 13.2% averagely, which led to a higher egg mass by 131 g/hen throughout the whole trial period. Abdominal fat and skinfold of XOS treatments were decreased (p<0.001) by 26.1% and 18.6%, respectively; large follicles and ovary weight were increased (p<0.001) by 0.73 follicle/hen and 18.6%, respectively. For serum parameters, cholesterol and triglyceride were decreased (p<0.001) by 17.5% and 29.2%, respectively; luteinizing hormone, follicle-stimulating hormone, and progesterone were increased (p≤0.001) by 16%, 31%, 29%, respectively; adiponectin and visfatin were increased (p<0.001) by 34% and 44%, respectively; but chemerin and leptin were decreased (p≤0.001) by 22% and 14%, respectively. With the increased XOS doses, linear decreases (p<0.05) were found on abdominal skinfold and serum triglyceride. Conclusion: The obtained data indicate that XOS can be used as an additive to improve fecundity by beneficially modulating fat deposition, lipid metabolism, reproductive hormones, and adipokines of hens at the late cycle of reproduction.

• Development and Reproduction
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• v.15 no.3
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• pp.257-263
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• 2011

Gonadal development and reproductive cycle of Aplysia kurodai inhabiting the coastal waters of Jeju Island, Korea were investigated based on monthly changes of gonadosomatic index, gametogenesis, and developmental phases of ovotestis. A. kurodai was simultaneous hermaphrodite; the ovotestis generally embedded in the posterior dorsal surface of the brownish digestive gland. The ovotestis is composed of a large number of follicles, and both oocytes and sperm are produced in the same follicles. In the sampling periods, the adult A. kurodai population have characteristic of seasonal pattern present during only 10 months. The reproductive cycle can be grouped into the following successive stages in the ovary: inactive (December to February), active (December to April), mature and spawning (April to September). The gonadal development of A. kurodai coincided with rising temperature, and spawning occurred from April to September, when the temperature was high. The histological observations of the ovotestis suggested that this species have a single spawning season that extend over six months.

• Animal cells and systems
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• v.5 no.1
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• pp.37-44
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• 2001

Gonadal development, reproductive cycle, gonad index, meat weight rate, and first sexual maturity of the top shell, Omphalius rusticus were Investigated monthly by histological observations. Specimens were collected from the west coast of Korea during the period from January to December in 1999. O. rusticus is dioecious and oviparous. The gonad is widely situated on the surface of the digestive g1and located in the posterior spiral meat part in the shell. The ovary and the testis were composed of a number of oogenic follicles and several spermatogenic follicles, respectively. Ripe oocytes were approximately 120-130 $\mu$m in diameter. The meat weight rate peaked in June (27.7%), and then rapidly decreased in September (19.5%). Monthly changes in the gonad index in both sexes reached the maximum in June, and then sharply decreased in September. Percentages of first sexual maturity of female and male snails ranging from 9.0 to 9.9 mm in shell heights were 58.3% and 54.5%, respectively, and 100% in those over 11.0 mm in both sexes participated in reproduction. Reproductive cycle of this species can be categorized into five successive stages: in females, early active (October to April), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to January): in males, early active (November to March), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to December). Gonadal development, gametogenesis, reproductive cycle, and spawning were closely related to the seawater temperature.

• Development and Reproduction
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• v.22 no.1
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• pp.1-8
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• 2018

The annual reproductive cycle of the Korean endemic slender catfish, Silurus microdorsalis, was examined histologically regarding water temperature and day length of habitat, gonadosomatic index (GSI), and development characteristics of female and male gonads. The maximum GSI value was found in May, $1.23{\pm}0.33$ and $11.77{\pm}3.23$ for male and female respectively (habitat water temperature $21.5^{\circ}C/13.59hr$ day length). On the other hand, the minimal level was $0.63{\pm}0.10$ in July ($26.5^{\circ}C/14.17$) for male and $1.36{\pm}0.08$ in October ($20^{\circ}C/11.2hr$) for female. We compared and calculated the stages of testis and ovary development process in order to determine the germ cell development characteristics and the reproductive cycle. According to results, we classified the annual reproductive cycle of the slender catfish into five stages: Growing phase (December-February), Mature phase (March-April), Ripe and spawning phase / Releasing phase in male (May-June), Degenerative phase (July-August), and Resting phase (September-November).

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.263-270
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• 2010

Luteal cells produce progesterone that supports pregnancy. Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism. In the present study, the corpus luteum (CL) in early pregnancy established from luteal phase and pregnant phase was analyzed. The first study determined progesterone changes in the bovine CL at day 19 (early maternal recognition period) and day 90 in mid-pregnancy and compared them to the CL from day 12 of the estrous cycle. CL alternation was tested using two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF). Comparing CL from luteal phase to those from pregnant phase counterparts, significant changes in expression level were found in 23 proteins. Of these proteins 17 were not expressed in pregnant phase CL but expressed in luteal phase counterpart, whereas, the expression of the other 6 proteins was limited only in pregnant phase CL. Among these proteins, vimentin is considered to be involved in regulation of post-implantation development. In particular, vimentin may be used as marker for CL development during pregnancy because the expression level changed considerably in pregnant phase CL tissue compared with its luteal phase counterpart. Data from 2-DE suggest that protein expression was disorientated in mid pregnancy from luteal phase, but these changes was regulated with progression of pregnancy. These findings demonstrate CL development during mid-pregnancy from luteal phase and suggest that alternations of specific CL protein expression may be involved in maintenance of pregnancy.