• Korean Journal of Veterinary Research
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• v.32 no.2
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• pp.275-280
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• 1992

To investigate the age at puberty and the seasonal breeding in Korean native goats, progesterone concentrations were measured in blood. Blood samples were collected from 8 goats at 10 day intervals from 2 months of age until the first estrus after birth, and then every 5 days for a further estrous cycle and the seasonal breeding. The mean age and weight at puberty were $195{\pm}57$ days($mean{\pm}S.D.$, range : 107~260 days) and $11.1{\pm}0.9kg$(range : 9.8~12.0kg), respectively. The mean age at first pregnancy after birth was $241{\pm}109$ days(range : 107~273 days). The estrus was observed 47.6% from October to December, and was highest in fall(38.1%) and lowest in spring and summer(14.3%). However, the estrus was observed every season. About 67% of total conception occurred form October to January. The parturition occurred 41.7% in spring, 25.0% in summer and winter, and 8.3% in fall, respectively. These results suggest that Korean native goats do not have a breeding season, but the reproductive activity is influenced by the season.

• Journal of Embryo Transfer
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• v.17 no.2
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• pp.117-121
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• 2002

This study was carried out to investigate the in vitro fertilization rate of canine immature oocytes cryopreserved by vitrification freezing. The vitrification solutions of EPS and EDS were consisted of 40％ ethylene glycol 18％ Ficoll and 0.3M sucrose, and 20％ ethylene glycol, 16.5％ DMSO and 0.5M sucrose in TCM-199 medium supplemented with 10％ FCS, respectively. The oocytes were exposed The developmental rate of in vitro cultured oocytes recovered from ovaries collected at different stages of the reproductive cycle were 3.8％, 10.7％, 46％, respectively. to EFS or EDS at $25^{\circ}C$ and loaded into straw fer 30 sec. The straws was slowly immersed into L$N_2$. Fertilization and survival rate was defined as development rate on in vitro culture or FDA-test. 1. The fertilization rate after vitrification freezing of immature oocytes at 1, 6, 12 and 24 hrs after collection from ovaries was very low(5.3％～31.4％) than the unfrozen oocyte(60.0％). And the fertilization rate after vitrification freezing of immature oocytes was very higher than that of mature oocytes. 2. The survival rate after vitrification freezing of immature oocytes at 1, 6, 12 and 24 hrs after collection from ovaries was 55.0％, 40.0％, 28.6％ and 17.1％, respectively. And the survival rate after vitrification freezing of immature oocytes was slightly higher than that of mature oocytes.

• Development and Reproduction
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• v.24 no.1
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• pp.43-52
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• 2020

NUCB2/nesfatin-1 known to regulate appetite and energy homeostasis is expressed not only in the hypothalamus, but also in various organs and tissues. Our previous reports also demonstrated that NUCB2/nesfatin-1 was expressed in the reproductive organs, including the ovaries, uterus, and testes of mice. However, it is yet known whether NUCB2/nesfatin-1 is expressed in the oviduct and how its expression is regulated. Therefore, we investigated the expression of NUCB2/nesfatin-1 in the oviduct and its expression is regulated by gonadotropin. Immunohistochemical staining results showed that nesfatin-1 protein was localized in epithelial cells of the oviduct. As a result of quantitative real-time PCR (qRT-PCR) and Western blot, NUCB2/nesfatin-1 was detected strongly in the oviducts. During the estrus cycle, NUCB2/nesfatin-1 expression in the oviducts was markedly higher in the proestrus stage than in other estrus stages. In order to elucidate whether the expression of NUCB2 mRNA is controlled by the gonadotropins, we injected PMSG and hCG and measured NUCB2 mRNA level in the oviduct after injection. Its level was increased in the oviduct after PMSG injection, but no significant change after hCG injection. In addition, NUCB2 mRNA levels were markedly reduced after ovariectomy, while recovered after 17β-estradiol (E2) injection, but not by progesterone (P4). This study demonstrated that NUCB2/nesfatin-1 is highly expressed in the oviduct of mouse and its expression is regulated by E2 secreted by the ovaries. These results suggest that NUCB2/nesfatin-1 expressed by the oviduct may affect the function of the oviduct regulated by the ovaries.

• Journal of Embryo Transfer
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• v.26 no.2
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• pp.105-109
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• 2011

Ovulation synchronization (ovsynch) has proved to increase the number of insemination in cattle by overcoming the problems of heat detection. The aim of this study was to do ovsynch in water buffaloes where heat detection is a major reproductive problem and to determine the conception rates after timed artificial insemination (TAI). Twenty cyclic buffaloes at ${\geq}$ 60 days postpartum were selected by examining 24 unobserved estrus buffaloes based on milk progesterone assay (progesterone concentration ${\geq}$ 1.0 ng/ml) from the Mymensingh district of Bangladesh. Ovsynch treatment regimen was started irrespective of the stage of estrous cycle. Gonadorelin (500 ${\mu}g$) was injected intramuscularly at Day 0 followed by Alfaprostol (8 mg) at Day 7. A second injection of Gonadorelin was given at Day 9 and TAI was done with frozen semen from Mediterranean buffalo bulls at 16~20 hours of the second Gonadorelin injection. Milk progesterone ELISA at Day 10~12 post AI confirmed ovulation in 16 out of 20 (80%) buffaloes (progesterone concentration ${\geq}$ 1.0 ng/ml). High progesterone concentration (${\geq}$ 1.0 ng/ml) at Day 10~12 and Day 22~24 of AI showed pregnancy in six out of 20 (30%) buffaloes. Pregnancy was further confirmed by ultrasonography at Day 40 in these six buffaloes. In conclusion, ovsynch followed by TAI could be applied in cyclic buffaloes for overcoming the estrus detection problems; however, more studies are needed to increase the conception rate.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.11
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• pp.1574-1580
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• 2009

To evaluate the effect of different housing systems on sow behavior, 80 gilts were randomly allocated at puberty to four treatments: i) sow stall in gestation followed by farrowing crate (SC), ii) group housing with individual feeding in gestation followed by farrowing crate (GC), iii) ESF (Electronic Sow Feeding) system in gestation followed by farrowing crate (EC), and iv) ESF system followed by group farrowing pen (EG). Behavioral observations were carried out on a total of 16 animals per treatment at the following stages: first day of allocation to housing treatment, day of service, 80 days after service, 109 days after service on entry to farrowing accommodation, 24 h before farrowing, day of farrowing, 14, 27 and 28 days after farrowing, at weaning. On each occasion, individual animals were observed for a 24 period with one minute time sampling. There were significant differences (p<0.001) between stages of the reproductive cycle for all the behavior patterns in all treatments. On the first day in experimental housing treatments, sows spent more time rooting and dog-sitting. Activity and investigatory behavior decreased as pregnancy progressed. An activity peak was apparent just before farrowing, followed by a high level of inactivity on the day of farrowing. Time spent active, eating and drinking increased as lactation progressed, and greatest activity and locomotion was seen immediately following weaning. There were significant differences between housing treatments (p<0.01) for standing, moving, eating, drinking, dog-sitting and lying. During pregnancy SC sows spent more time standing, rooting, drinking and dog sitting, while EC sows spent less time rooting and drinking and more time lying. During lactation, GC sows spent more time standing, moving and eating, less time dog sitting and lateral lying. Nursing frequency was reduced in GC sows (p<0.001). The maternal and piglet behaviors were influenced strongly by environment during lactation. However, it was also shown that previous housing history can influence the maternal behavior in the pre-farrowing stage and during early lactation.

• Reproductive and Developmental Biology
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• v.29 no.2
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• pp.121-125
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• 2005

The present study was performed to determine the ability of canine oocytes to achieve nuclear maturation according to oocyte diameter and different culture environments. All of the collected oocytes were classified by grade 1 to 3 and by their diameters such as $<100{\mu}m,\;<100{\mu}m\;to\;<110{\mu}m,\;<110{\mu}m,\;to\;<120{\mu}m,\;>120{\mu}m,$. Oocytes were cultured in culture medium supplemented with $10\%\;FBS,\;0.4\%\;BSA,\;10\%$ porcine follicular fluid (pFF), $10\%$ canine serum (CS), or $10\%$ canine estrus serum (CES). The mean number of oocytes recovered from estrus status ovaries was significantly higher than that of anestrus status ovaries (p<0.01). The maturation rate of grade 1 oocytes $(>120{\mu}m)$ was significantly higher than that of the other groups (p<0.05). Nuclear maturation to MI to MII in diameter of $>110{\mu}m$ groups was significantly higher than that in $<100{\mu}m$ group (p<0.05). The oocytes cultured in $10\%$ FBS­supplemented group were significantly higher rate of GVBD compared to the other supplemented groups (p<0.05), and oocytes maturation to MI to MII in $10\%$ FBS-, $0.4\%$ BSA-, and $10\%$ pFF-supplemented groups were significantly higher than those in $10\%$ CS-supplemented group (p<0.05). Based on these results, the estrus status and the size of oocyte affect positively to improve nuclear maturation of canine immature oocytes in vitro. Among several protein sources, porcine follicular fluid was the most effective supplementation to culture medium to achieve higher in vitro maturation rate.

• Reproductive and Developmental Biology
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• v.38 no.2
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• pp.79-84
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• 2014

MicroRNAs (miRNAs) are approximately 22 nucleotides of small noncoding RNAs that control gene expression at the posttranscriptional level through translational inhibition and destabilization of their target mRNAs. The miRNAs are phylogenetically conserved and have been shown to be instrumental in a wide variety of key biological processes including cell cycle regulation, apoptosis, metabolism, imprinting, and differentiation. Recently, a paper has shown that expression of the miRNA-302/367 cluster expressed abundantly in mouse and human embryonic stem cells (ESCs) can directly reprogram mouse and human somatic cells to induced pluripotent stem cells (iPSCs) efficiently in the absence of any of the four factors, Oct4, Sox2, c-Myc, and Klf4. To apply this efficient method to porcine, we analyzed porcine genomic sequence containing predicted porcine miRNA-302/367 cluster through ENSEMBL database, generated a non-replicative episomal vector system including miRNA-302/367 cluster originated from porcine embryonic fibroblasts (PEF), and tried to make porcine iPSCs by transfection of the miRNA-302/367 cluster. Colonies expressing EGFP and forming compact shape were found, but they were not established as iPSC lines. Our data in this study show that pig miRNA-302/367 cluster could not satisfy requirement of PEF reprogramming conditions for pluripotency. To make pig iPSC lines by miRNA, further studies on the role of miRNAs in pluripotency and new trials of transfection with conventional reprogramming factors are needed.

• Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.22-30
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• 2011

Vitellogenin (Vg) is the precursor of vitellin (Vn), which is the major yolk protein in nearly all oviparous species, including fish, amphibians, reptiles, and most invertebrates. It is one of the most important factors during reproduction, and numerous studies have shown that Vg genes are markers of the reproductive cycle and effecter genes induced by endocrine-disrupting chemicals (EDCs). Previously, we isolated two distinct cDNAs encoding vitellogenin homologs Pj-Vg1 and Pj-Vg2 from Pandalus shrimp Pandalopsis japonica. In this study, full-length genomic sequences of Pj-Vg1 and Pj-Vg2 were determined using a PCR-based genome walking strategy. Isolated Pj-Vg1 and Pj-Vg2 genes were 11,910 and 11,850 bp long, respectively. Both Pj-Vg genes had 15 exons and 14 introns, and the splicing sites were also the same, suggesting that they arose via gene duplication. The similar structural characteristics of decapod Vg genes suggest that they are all orthologs that evolved from the same ancestral gene. Analysis of Pj-Vg1 and Pj-Vg2 expression revealed that the relative copy numbers of Pj-Vg1 and Pj-Vg2 were similar in the hepatopancreas, whereas Pj-Vg2 transcripts were also detected in the ovary. Expression of both Pj-Vg genes was induced in hepatopancreas of mature individuals, whereas only Pj-Vg2 transcripts were upregulated in the ovaries from mature animals, suggesting that both Pj-Vgs are important for oocyte development. A strong positive correlation was found between Pj-Vg1 and Pj-Vg2 transcripts in the same individual, indicating they are under the same control mechanisms. Additionally, a positive correlation was found between ovarian and hepatopancreatic Pj-Vg2 transcripts, suggesting that its dual expression is regulated by similar physiological conditions. Knowledge of the similarities and differences between the two vitellogenin-like genes, Pj-Vg1 and Pj-Vg2, would help us to understand their roles in reproduction and other physiological effects.

• The Korean Journal of Malacology
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• v.26 no.1
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• pp.97-105
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• 2010

Annual gonad development of the rock shell, Thais clavigera distributed in Jeju Port was investigated over a 12 month period from March 1998 to February 1999. Monthly change in gonad development was examined using histology. Gametogenesis of T. clavigera in the study area initiated as early as in October and fully ripe eggs could be observed from May to July. Percent gonad area (PGA) also increased rapidly from May to July then dropped in August when the water temperature remained $22.6-24.5^{\circ}C$, suggesting that rock shell released their eggs during this period. All female rock shell collected during the course of study exhibited pseudo-penis in the head, indicating that a certain level of imposex had progressed in the study site. Relative penis size index (RPSI), an indicator of level of imposex phenomenon varied 59.5-173.4% and this value was relatively higher than the index reported from elsewhere. It was believed that such imposex phenomenon observed in T. clavigera was caused by endocrine disruption by chemical contaminants such as TBTs released from biocidal paints in the port environment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.4
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• pp.349-356
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• 2006

Gonad development in the sandfish Arctoscopus japonicus was investigated using a histological method. Specimens were collected monthly from April 2003 to March 2004, in the East Sea of Korea. The gonadosomatic index (GSI) of females began to increase in August, reached a maximum in November, and declined sharply in December. By contrast, in males, the GSI began to increase in June and reached a maximum in August. The annual reproductive cycle of A. japonicus can be divided into four successive stages in females: the early growing (January-March), late growing (April-August), ripe and spent (September-November), and recovery (December) stages. Males passed through early growing (January-April), late growing (May-July), ripe and spent (August-November), and recovery (November-December) stages. These results indicate that the spawning season was from October to December. The egg diameter of mature oocytes was 3.12$\pm$0.02 mm. The relationship between fecundity (F$_e$) and body length (BL) was F$_e$=0.4693BL$^{2.6825}$. Fecundity ranged from 483-2,254 eggs in a body length of 14.3-22.9 cm and increased with body length. The body length at 50% maturity was 14.80 cm, which corresponded to an age of 2.40 years.