• 한국수정란이식학회지
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• 제30권4호
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• pp.345-350
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• 2015

In the last 10 years, porcine somatic cell nuclear transfer to generate transgenic pig has been performed tremendous development with introduction and knockout of many genes. However, efficiency of porcine somatic cell nuclear transfer is still low and embryo transfer (ET) is one of important step for production efficiency. In porcine ET for production of transgenic cloned pig, we can consider many of points to increase production rates. In respect of seasonality and weather, porcine ET usually is not performed in summer and winter. Cloned transgenic embryos must be transferred into reproductive tracts of recipients where embryos are located after natural fertilization with similar estrous cycle. If cloned embryos with 2~4 cell stage are transferred, they must be transferred into oviducts in periovulatory stage. Number and deposition sites of transferred cloned embryos are important. And we must compare the methods of ET between surgical and non-surgical ones in respect of production efficiency. Sow recipients after natural estrus is most preferred recipients however its cost is must be considered. Here we will review many of current studies about porcine embryo transfer to increase production efficiency of transgenic pigs and strategies for further studies.

• 한국동물생명공학회지
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• 제35권2호
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• pp.171-176
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• 2020

Advancing the estrous cycle of mares is an essential breeding strategy that is routinely conducted by Thoroughbred breeders to improve economic outcomes. For this purpose, Equilume light masks have been developed as an alternative to existing technologies such as artificial lighting or hormonal treatments because they are considered as valid as existing methods with additional animal welfare advantages. For example, with the Equilume light masks, horses can be let out into the pasture, whereas they have to be kept indoors during lighting treatment. Because the function of Equilume light mask on the estrous cycle of mares is influenced by environmental factors such as nutrition condition and temperature, Equilume light mask should be studied in various environments. The objective of the present study was thus to verify the effect of Equilume light masks on the onset of the estrous cycle in Thoroughbred mares in South Korea. Mares were randomly selected and separated into two groups at two Thoroughbred horse breeding farms. The mares in the treatment group were equipped with Equilume light masks from November 18 to February 10 the following year. The body condition, the number and size (> 35 mm) of uterine follicles, and the uterine horn score of the mares were assessed on January 6 and February 10. The body condition scores were not different between the two groups. The treatment with the Equilume light mask had no positive effects on developing follicles and the reproductive tract. In conclusion, the use of Equilume light masks did not influence the seasonal resumption of the estrus cycles in Thoroughbred mares in South Korea.

• 한국수산과학회지
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• 제22권5호
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• pp.342-350
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• 1989

낙동강 하구지역에 서식하는 자주새우를 대상으로 1988년 6월부터 1989년 5월까지 성성숙과 산란에 대하여 조사한 결과는 다음과 같다. 1. 난소는 두흉부의 심장 하방에 위치하며 심장을 중심으로 전방은 촉각동맥 및 안동맥을 둘러싸고 둥글게 융합되어 있고, 후방은 1쌍의 관상으로 복부 2마디까지 뻗혀있다. 정소는 심장직하에 위치하며 심장을 중심으로 전방은 관상으로 곡정관의 형태를 취하고 있으며 후방은 1쌍의 관상의 형태를 띠고 있고, 이곳으로부터 연결된 저정낭이 제5흉지에 개구되어 있다. 2. 난자 및 정자의 배우자형성은 계절과 관계없이 단기간에 반복되고 있으며, 생식소상피의 전 구역에서 동시에 이루어지고 있다. 완숙난의 장경은 $430{\mu}m$ 전후이고, 변태된 정자는 두부 핵질이 뚜렷한 타원형의 구조를 나타낸다. 3. 생식주기는 약 40일을 간격으로 단주기성이며, 11월을 전후한 동계를 제외하고는 주년 산란종이다. 4. 포란된 난의 부화기간은 수온 $21^{\circ}C\~24^{\circ}C$의 실내사육에서 $12\~14$일이 소요되었다. 5. 포란된 개체의 평균 부화유생수는 1,602마리였고, 전장 32mm에서 1,372마리, 38.2개개에서 1,650마리였다.