生物絮团在斑节对虾养殖系统中的形成条件及作用效果

摘要

为确定斑节对虾（Penaeus monodon）养殖系统中生物絮团形成所需的最适碳源及添加量，试验选取葡萄糖、蔗糖、糖蜜3种碳源按碳（C）与氮（N）比（C/ N）为20：1添加，再按日投饲量的0％、25％、50％、75％和100％添加蔗糖，以期获得其最适添加量。结果显示，添加3种不同糖作为碳源均可以显著提高斑节对虾的特定生长率（P ﹤0.05），而添加蔗糖可以显著提高斑节对虾的成活率（P ﹤0.05）；与其他组相比，添加75％的蔗糖组可以显著提高斑节对虾的特定生长率和成活率（P ﹤0.05），促进异养细菌和浮游植物的繁殖，水体氨氮（NH4-N）、亚硝酸氮（NO2-N）等有害物质的浓度较低，过多的添加蔗糖却会起到反作用。结果表明添加75％的蔗糖最适合生物絮团在斑节对虾养殖系统中形成，并促进斑节对虾的生长。%To determine the optimum carbon source and dosage for bio-floc formation in Penaeus monodon culture system,we added three kinds of carbon source including glucose,sucrose and molasses in the culture system at C/ N ratio of 20: 1. The sucrose was added into the culture system at daily feeding ratios of 0% ,25% ,50% ,75% and 100%. Results show that all carbon sources test-ed in the present study could significantly increase the special growth rate(SGR)of P. monodon(P ﹤ 0. 05). Sucrose could signifi-cantly increase the survival rate(SR)of P. monodon(P ﹤ 0. 05). Compared with the other groups,75% of sucrose could significant-ly improve the SGR and SR of P. monodon(P ﹤ 0. 05),and sucrose could promote heterotrophic bacteria and phytoplankton reproduc-tion,and indirectly reduce concentration of harmful substances in water such as NH4-N and NO2-N,but adding excessive sucrose would be counterproductive. The results reveal that adding 75% of sucrose was the most suitable condition for bio-floc formation in P. monodon culture system,which could promote the growth of P. monodon.