본 연구는 케이지와 평사 사육환경이 산란종계의 생산성에 미치는 영향을 알아보고자 실시하였다. 케 이지 또는 평사 사육환경을 제외한 모든 환경 조건은 동일한 산란종계 무창 계사를 선정하여 진행하였 다. 총 48주간 산란 종계의 산란율, 폐사율, 수정율 및 부화율을 측정하였다. 산란초기 산란율은 케이 지 사육 환경에서 높았으나, 전 구간을 보았을 때 37주 이후부터는 평사 사육이 월등히 높게 나타났다. 폐사율은 암컷 종계의 누적 폐사율에는 유의한 차이가 없었지만, 수컷의 폐사율은 케이지 사육환경에서 유의적으로 높게 조사되었다. 수정율은 전 구간 평사 사육이 월등히 높게 나타났다. 부화율에서도 평사 사육이 케이지 사육보다 높게 나타났다. 본 연구결과 평사 사육방식이 케이지 사육방법보다 산란종계의 수정율, 부화율 및 폐사율에서 우수한 것으로 조사되었다.

Porcine has been known to have a great impact on the studies of organ transplantation, biomaterial production and specific biomodel development such as transgenic animals. To achieve such therapeutic purposes, establishment of porcine embryonic stem cells (pESCs) will be needed. Especially, in vitro differentiation toward neural cells from pESCs can be a useful tool for the study of early neural development and neurodegenerative disorders. In addition, these cells can also be used in cell replacement therapies and drug development for neuroprotective and/or neurotoxic reagents. Although several studies reported the successful isolation of pES-like cells, it has been a big challenge to determine optimal conditions to generate pESCs without loss of pluripotency for a long time. The present study was performed for generation and characterization of putative pESCs, and differentiation into neurons and astrocytes. In this study, porcine blastocysts were produced by parthenogenetically activated oocytes. The putative pESCs were cultured in pESC growth media supplemented with a growth factor and cytokines (bFGF, LIF and SCF). Subculture of pESCs was conducted by mechanical dissociation using syringe needles after 4-5 days of incubation. As results, six putative pESC lines were maintained over thirty passages. The putative pESCs were compact, round, flat, and single layered, which were similar to human embryonic stem cell morphologically. Six pES-like cells were positive for alkaline phosphatase activity at every three passages. Furthermore, Oct-3/4, Sox-2, Nanog and SSEA-4 were shown to be expressed in those cells. Also, normal karyotypes of pESCs were observed by Giemsa-staining. Differentiation potential into the three germ layers of the putative pESCs was demonstrated by the formation of embryoid bodies (EB). Besides, the study of ESC is very important in aspect of its application to not only the cell-based replacement therapies but also cellular differentiation research. Our results also showed that RA and N2 supplements activated the neural differentiation in pESC5. Neurofilament-l60 were expressed in neural precursor cells. The expression of markers for specific neural lineages, such as Microtubule-associated protein-2 expressed in matured neuron, was also induced from embryonic neural progenitors. In summary, the pESCs were generated from the parthenogenetically activated blastocysts and the typical characteristics of the cells were maintained for the long term culture. Furthermore, it was successful to differentiate the pESCs into various neural lineages through in vitro neurogenesis system. Eventually, pESCs will be excellent biomedicine in incurable and/or zoonotic diseases by regenerating the damaged tissue.

Canine parvovirus (CPV) type 2a (CPV-2a) has recently been identified as the main genotype circulating in the dog population in South Korea. Although CPV vaccines protect domestic dogs from CPV-2 infection, the efficacy of commercial live or inactivated CPV vaccines against CPV-2a has not been reevaluated. In this study, dogs were immunized with one of 7 commercial CPV vaccines (4 modified live and 3 inactivated vaccines) followed by challenge with CPV-2a strain, KV0901 that had been isolated from naturally infected dog in 2009. All dogs vaccinated twice with 4 commercial modified live CPV vaccines were seroconverted (geometric mean HI titer > 190.2) and most of dogs were completely protected against virulent CPV-2a strain infection. The dogs inoculated with 3 commercial inactivated CPV vaccines were also seroconverted and showed a slight loss of appetite and light diarrhea for 4 days after challenge and returned to normal at 5 days post challenge. However, the non-vaccinated dogs revealed the typical clinical signs of CPV infection including haemorrhgic diarrhea. In conclusion, the 4 live CPV vaccines licensed in Korea cross-protected dogs against virulent challenge with CPV-2a and are applicalble to pet dogs for the prevention of CPV infection.