잉어, Cyprinus carpio를 대상으로 고수온 스트레스 발생 시 코티졸 호르몬 변화 및 누적 사망 률을 조사하였다. 수온 변화에 따른 20℃, 24℃ 및 28℃ 실험군의 코티졸 변화는 수온 변화 후 6시간에 코티졸 함량이 증가하다가 24시간 이후부터 감소하여 20℃ 및 24℃ 실험군은 실험 전 의 코티졸 함량에 가까운 수치로 감소하였다. 48시간의 28℃ 실험군 코티졸 함량은 실험 전의 코티졸 함량보다 높았으나 24시간의 코티졸 함량보다는 유의한 차이를 보이며 감소하였다. 반면, 32℃ 실험군은 수온 변화 후 6시간부터 코티졸 함량이 증가하여 24시간에 코티졸 함량 이 최대치로 증가하였으며 48시간까지 코티졸 함량이 감소하지 않고 유지되는 경향이 나타났 다. 20℃, 24℃ 및 28℃ 실험군은 수온 변화 후 12시간까지 누적 사망률이 증가하다가 그 이 후부터 사망하는 개체가 발생하지 않았으나, 32℃ 실험군은 실험 종료 시(48시간)까지 지속적 으로 누적 사망률이 증가하는 경향이 나타났다. 본 연구로 도출된 결과를 이용하여 호르몬 분 석을 통해 특정지역의 폐사 위험 정도를 확인할 수 있는 방안으로 활용 가능할 것이다.

The plasma cortisol of nurserypigs was examined using an outdoor efficacy testwith a digital content-based approach in animal welfare convergence types. Nine nurserypigs,without discriminating between female and male, were classified into 2 groups of 3 pigs each: control and group 1 (effect+nature), control and group 2(effect+nature+music). The control group was the same for group 1 and 2 to compare the effects using a t-test. There was no significant difference in plasma cortisol levels between the control group and group 1 until 4 h after stress induction. However, significant differences were subsequently found between the control group and group 1 from 8 h to 72 h (p<0.05). Further, plasma cortisol was not affected in group 2 at 0 h through 8 h and 72 h. At 12 h through 48 h, group 2 showed a reduction in plasma cortisol level compared to the control group(p<0.05). These results indicated that after stress induction, applying effect plus nature or effect plus nature plus music can effectively decrease plasma cortisol levels in nursery pigs within8 h through 72 h and may serve as a better model for digital content-based approach in animal welfare convergence types.

This study was conducted to determine the stress response [ethological (operculum movement number (OMN)), hematological (hematocrit and hemoglobin), biochemical (glucose, cortisol and glutamic oxaloacetic transaminase (GOT))] in red spotted grouper, Epinephelus akaara during exposure of different water temperature in winter season. This species (Total length, 18.56±0.34 cm) previously maintained in water temperature of 15°C were transferred to 15, 20 and 25°C. During experimental period (7 days), OMN, hematocrit (Ht), glucose and GOT values were significantly high in 15°C when compared to 20 and 25°C. Hemoglobin value was also increased at 15°C, but no significant differences. There was no differences in cortisol levels among the temperature groups. No fish mortality was observed during the experimental period. From these results, 15°C is likely more stressful to red spotted grouper than 20°C and 25°C. These observations confirm that red spotted grouper adapts better to temperatures between 20 and 25°C during the winter season.

We investigated the changes in plasma sex steroid hormones, testosterone (T), estradiol- (), 17,-dihydroxy-4-pregnen-3-one (), 11-ketotestosterone (11KT) and cortisol levels from ribbed gunnel, Dictyosoma burgeri in associated with annual reproductive cycle. The gonadosomatic index (GSI) of females increased from November, peaked in February and decreased rapidly from March. The GSI of males also increased from November, peaked in January and then decreased gradually. In females, levels increased and remained high from December to February. The levels of T showed a similar tendency and correlated (=0.898, p<0.01) with levels. The levels of increased rapidly in February () and peaked in July (). Cortisol level was peaked in March and correlated with levels (=0.696, p<0.01). In males, the levels of T was peaked in January and then decreased rapidly. The levels of 11KT were remained high from October to January. On the other hand, the levels of fluctuated during reproductive cycle. These results suggest that plasma sex steroids in ribbed gunnels have annual periodicity, and that cortisol may involve in maturation of females.

We investigated the changes in plasma sex steroid hormones, testosterone (T), estradiol-17β (E2), 17,20 β-dihydroxy-4-pregnen-3-one (17α20βOHP), 11-ketotestosterone (11KT) and cortisol levels from ribbed gunnel, Dictyosoma burgeri in associated with annual reproductive cycle. The fish were collected at the coastal waters of Dadaepo, Busan, Korea from August 2002 to March 2003. Body weight, liver weight and gonad weight were measured for calculation of hepatosomatic index (HSI) and gonadosomatic index (GSI). Plasma steroid and cortisol levels were measured by radioimmunoassay and data were analyzed using the Kruskal-Wallis test and the Spearman rank correlation. The GSI of females increased from November, peaked in February (13.21±2.27) and decreased rapidly from March (1.05±0.23). The GSI of males also increased from November, peaked in December (0.36±0.12) and remained high to February. In females, E2 levels increased and remained high from December to February (19.81±7.46～22.85±6.18 ng/ ㎖). The levels of T showed a similar tendency and correlated (rs=0.813, p=0.0001) significantly with E2 levels. The levels of 17α20βOHP increased rapidly in February (4.78±1.01 ng/㎖) and peaked in July (5.08±0.65 ng/㎖). Cortisol level was peaked in March (2081.07±1140.02 ng/㎖) and correlated significantly with 17α20βOHP levels (rs=0.790, p=0.0001). In males, the levels of T was peaked in January (2.43±0.17 ng/㎖) and then decreased rapidly. The levels of 11KT were remained high from October to January (3.27±1.55～4.28±1.53 ng/㎖) and correlated significantly with T levels (rs=0.513, p=0.002). On the other hand, the levels of 17α20βOHP fluctuated during reproductive cycle and the variation pattern of cortisol levels were similar to females. These results suggest that plasma sex steroids in ribbed gunnels have annual periodicity, and that cortisol may involve in maturation of females.