본 연구는 vitamin $B_{12}$의 첨가에 따른 담수산 rotifer, Brachionus calyciflorus의 유성생식율 및 내구란 생산을 조사하였다. Vitamin $B_{12}$의 첨가방법은 rotifer의 먹이생물인 농축 담수산 Chlorella에 첨가하여 공급하였고 실험용기는 250mL 삼각플라스크에서 실시하였다. Rotifer의 최고밀도는 vitamin $B_{12}$의 첨가량이 높을수록 낮게 나타났고 6ppm구에서 가장 낮은 138개체/mL를 보였다. 유성생식 율과 수정률은 vitamin $B_{12}$의 첨가량이 많을수록 높아 6ppm구에서 각각 $63.0\%$와 $89.6\%$로 조사되었다. mL당 내구란 생산은 1.5 ppm구에서 231개/mL로 가장 높게 나타났으나 다른 vitamin $B_{12}$의 첨가구와의 유의적인 차이는 없었고, Rotifer $10^6$개체당, Chlorella 건중량 (g) 당 내구란 생산량은 6ppm구에서 각각 11,259개, 121,252개로 가장 높게 나타났다 Vitamin $B_{12}$의 첨가량에 따라 형성된 내구란의 부화율은 vitamin $B_{12}$를 첨가한 실험구에서 $67.7sim80.9\%$의 부화율을 보여 첨가하지 않은 대조구 $48.2\%$보다 높게 나타났다. 따라서 담수산 rotifer, B. calyciflorus의 내구란 생산과 내구란의 부화율에 vitamin $B_{12}$가 영향을 미친 것으로 판단된다.
This study was performed to investigate the effect of vitamin $B_{12}$ addition on the production and hatching rate of resting egg of freshwater rotifer, Brachionus calyciflorus. Different concentrations of vitamin $B_{12}$ was added into concentrated freshwater Chlorella before fed to rotifer and rotifer was cultured in 250 mL flask. The maximum density of rotifer was 138 inds./mL at 6 ppm and it increased with an increase of vitamin $B_{12}$ addition. Mixis rate and fertilization rate of rotifer were $63.0\%$ and $89.6\%$, respectively, at 6.0 ppm. The production of resting eggs per mL was 231 eggs/mL at 1.5 ppm, but there was no significant difference among vitamin $B_{12}$ addition levels. The highest production of resting eggs per 10,000 rotifers and Chlorella dry weight (g) were 11,289 eggs and 121,252 eggs, respectively, at the 6 ppm. The hatching rate of resting egg was not significantly different among vitamin $B_{12}$ addition levels, but significantly higher than the control (without addition of vitamin $B_{12}$ ). These results showed that vitamin $B_{12}$ addition could affect production and hatching rate of resting egg of freshwater rotifer, B. calyciflorus.
