エソ筋原繊維タンパク質の水の状態と変性に及ぼすエビ頭部タンパク質加水分解物の影響に関する研究

長崎大学学位論文 学位記番号:博(生)甲第56号 学位授与年月日:平成17年3月18

Feeding effect of selenium enriched rotifers on larval growth and development in red sea bream Pagrus major

Feeding trials were conducted to investigate the effect of selenium (Se)-enriched rotifers on growth and development of red sea bream Pagrus major larvae. Fish were reared from fertilized eggs (98% hatch rate) to 20. days post hatch (dph) at 19. °C with two different food sources; non-enriched S-type rotifers (0.0. μg. Se/g D.W., control diet) or Se-enriched rotifers (2.2. μg. Se/g D.W., Se-enriched diet) at 10. rotifers/mL, respectively. On the last day of larviculture, the Se-enriched diet accelerated growth and developmental stage of fish larvae. The larvae fed Se-enriched rotifers were advanced in the following parameters compared to those fed control diet: total length (6.06 vs 5.53. mm), standard length (5.74 vs 5.26. mm), head length (1.46 vs 1.28. mm), eye diameter (0.57 vs 0.50. mm), the number of caudal fin rays (5.8 vs 1.9), and the proportion of individuals undergoing notochord flexion (55 vs 3%). Fish larvae of 20. dph showed higher Se concentration (9.5 ± 0.2. μg/g DW) with the Se-enriched diet than with the control diet (1.3 ± 0.3. μg/g DW), but there were no significant differences in the composition of polyunsaturated fatty acids which significantly affect larval growth and development. Therefore, the feeding of Se enriched rotifers enhanced growth and development of the red sea bream P. major larvae

Effects of tank shapes and aerations on survival, growth and swim bladder inflation of red seabream Pagrus major larvae

This study aimed to seek for the optimal condition for small-scale larviculture of red seabream Pagrus major larvae. We examined the effects of tank shapes and aerations, which were assumed to influence the larval survival, growth and swim bladder inflation of P. major larvae. Seawater (50-l) was filled into three cylindrical (CT: 1.7 × 103 cm2 water surface area, 30 cm deep)and six rectangular (RT: 1.8 × 103 cm2 water surface area, 28 cm deep) tanks. One air stone with 100 ml/min aeration rate was set at the bottom center of three CT and RT (RT1AS), and two air stones with 50 ml/min aeration rate were set at the half bottom center of three RT (RT2AS). Five hundred eggs were distributed into each experimental tank. Rotifers were fed to larvae at 10 individuals/mL on 3 days post hatching (dph) and their distribution in tanks were measured. Survival rate at 14 dph in CT (54.7 ± 11.0 %) and RT1AS (55.3 ± 6.0 %) were significantly higher than that in RT2AS (29.6 ± 9.3 %, p < 0.05). However, the growth of larvae was not significantly different between tank shapes and aerators. Swimbladder inflation rates were not different between tank shapes and aerations, however, CT (58.9±28.3 %) showed lower trend (RT1AS 94.4±6.9 %, RT2AS 92.2±10.7 %). Rotifer distribution in tanks was higher at tank bottom (p < 0.05). Low flow regions were observed along the side walls of the tanks and bottom areas in CT and RT1AS due to a single-pair vortex system and formed at the center (between air stones) and from the air stone to the tank walls in RT2AS due to two single-pair vortex systems. These low-flow areas were coincided with higher rotifer distribution areas at the tank bottom indicating that measuring rotifer density can estimate the flow in a tank. We recommend the rectangular tank with one air stone system for red seabream larvae