벼메뚜기는 분류학적으로 메뚜기목(Orthoptera), 메뚜기과(Acrididae)에 속하는 곤충으로 작물에 피해를 주는 해충으로 인식하고 있지만 예로부터 단백질 보충을 위하여 채집하여 튀기거나 볶음요리 로 이용해 왔다. 벼메뚜기는 갈색거저리, 쌍별귀뚜라미 등과 함께 식품공전에 등록되어 있으나 1년 1세대로 가을철에 채집하여 이용하는 실정으로 공급확대에 한계가 있다. 최근 우리나라에서 벼메뚜기를 사육하고자 하는 농가와 다양한 용도로 가공을 통해 이용하려는 수요가 점차 증가하고 있으나 연중사육기술이 개발되지 않아 대량사육하는 농가가 거의 없는 실정이다. 이에 벼메뚜기의 연중대량사육기술 뿐만 아니라 인공사료 및 자동화 사육시설 개발에 따른 생산비 절감 기술 개발이 필요한 실정이다. 벼메뚜기의 먹이로는 여름작물로 옥수수, 수단그래스, 겨울작물로 밀, 보리 등의 볏과작물이 있으며 많은 양의 생엽과 발육에 적합한 작물의 선발 및 볏과작물의 통곡실 가루를 이용한 인공사료의 개발로 먹이공급 부족 시 15~20일 급여 가능하며, 벼메뚜기 사육시설로 단독형, 연결형, 절충형 등의 사육시설을 개발하여 연결형 사육시설의 수확량과 생존율이 가장 높았으며, 예취 급이 노동력이 단독형의 16% 소요되었다.

Porcine spermatogonial stem cells (SSCs) prefer three-dimensional (3D) culture systems to 2D ones for the maintenance of self-renewal. Of the many 3D culture systems, agar-based hydrogels are candidates for supporting porcine SSC self-renewal, and there are various types of agar powder that can be used. In this study, we sought to identify an agar-based 3D hydrogel system that exhibited strong efficacy in the maintenance of porcine SSC self-renewal. First, 3D hydrogels with different mechanics were prepared with various concentrations of Bacto agar, lysogeny broth (LB) agar, and agarose powder, and the 3D hydrogel with the strongest alkaline phosphatase (AP) activity and greatest increase in colony size was identified for the different types of agar powder. Second, among the porcine SSCs cultured in the different 3D hydrogels, we analyzed the colony formation, morphology, and size; AP activity; and transcription and translation of porcine SSC-related genes, and these were compared to determine the optimal 3D hydrogel system for the maintenance of porcine SSC self-renewal. We found that 0.6% (w/v) Bacto agar-, 1% (w/v) LB agar-, and 0.2% (w/v) agarose-based 3D hydrogels showed the strongest maintenance of AP activity and the most pronounced increase in colony size in the culture of porcine SSCs. Moreover, among these hydrogels, the strongest transcription and translation of porcine SSC-related genes and largest colony size were detected in porcine SSCs cultured in the 0.2% (w/v) agarose-based 3D hydrogel, whereas there were no significant differences in colony formation and morphology. These results demonstrate that the 0.2% (w/v) agarose-based 3D hydrogel can be effectively used for the maintenance of porcine SSC self-renewal.

Despite many researches related with in-vitro culture of porcine spematogonial stem cells (SSCs), adherent culture system widely used has shown a limitation in the maintenance of porcine SSC self-renewal. Therefore, in order to overcome this obstacle, suspension culture, which is known to have numerous advantage over adherent culture, was applied to the culture of porcine SSCs. Porcine SSCs retrieved from neonatal testes were suspension-cultured for 5 days or 20 days, and characteristics of suspension-cultured porcine SSCs including proliferation, alkaline phosphatase (AP) activity, and self-renewal-specific gene expression were investigated and compared with those of adherent-cul-tured porcine SSCs. As the results, the suspension-cultured porcine SSCs showed entirely non-proliferative and significantly higher rate of AP-positive cells and expression of self-renewal-specific genes than the adherent-cultured porcine SSCs. In addition, long-term culture of porcine SSCs in suspension condition induced significant decrease in the yield of AP staining-positive cells on post-day 10 of culture. These results showed that suspension culture was inappropriate to culture porcine SSCs, because the culture of porcine SSCs in suspension condition didn’t stimulate proliferation and maintain AP activity of porcine SSCs, regardless of culture periods.