生物絮团–循环水养殖系统对对虾养殖水体净化效果的初步探究

Preliminary Study on the Purification Effect of Biofloc-Recirculating Aquaculture System on Shrimp Aquaculture Water

摘要: 为研究添加枯草芽孢杆菌形成的生物絮团加循环水养殖系统对凡纳滨对虾(Litopenaeus vannamei)养殖水体的净化效果和短期内能否达到平衡状态，在凡纳滨对虾循环水养殖系统水槽中，以不加菌和红糖为对照(A组)、加菌(B组)、加红糖(C组)及加菌和红糖(D组)进行短期(72 h)生物絮团净化循环水养殖水体试验，24 h生物絮团和12 h循环净化水质。结果显示，试验结束时B、C、D组的生物絮团体积显著高于A组(P < 0.05)，D组生物絮团体积显著大于B、C组(P < 0.05)。总氨氮(TAN)下降率D > C > B > A，D组TAN下降率(35.9 ± 5%)显著高于A、B、C三组(14.2% ± 8%、11.3% ± 4%、30.2% ± 5%) (P < 0.05)。A组${\text{NO}}_{\text{2}}^{-}\text{-N}$ 浓度升高10.1% ± 0.3%，D组的${\text{NO}}_{\text{2}}^{-}\text{-N}$ 下降率为49% ± 10.4%，显著高于B、C组(11.3% ± 0.2%、6.4% ± 0.5%) (P < 0.05)。D组TAN和${\text{NO}}_{\text{2}}^{-}\text{-N}$ 浓度在前24 h与生物絮团体积呈极显著负相关，后期基本趋于稳定。试验期间A、B、C组养殖水体中悬浮颗粒物数量均有升高，而D组悬浮颗粒物减少21.5 ± 3.9%，显著高于其他三组(P < 0.05)。试验后期各组水体中溶解氧浓度依次为A > B > C > D。试验期间各组pH均有所下降，结束时B、C、D组pH都显著低于A组(P < 0.05)。研究表明，枯草芽孢杆菌与红糖所形成的生物絮团和对虾循环水养殖系统结合模式可以在短期内达到平衡状态，并有效地净化养殖水体中TAN、${\text{NO}}_{\text{2}}^{-}\text{-N}$ 和悬浮颗粒物。

Abstract: To investigate the purification effect of biofloc formed by Bacillus subtilis plus recirculating aquaculture system (RAS) on Litopenaeus vannamei aquaculture water and whether a balance can be achieved in the short term, a short-term (72-h) biofloc-recirculating aquaculture system was used to purify aquaculture water in tanks for L. vanname with no bacteria and brown sugar as a control (group A), bacteria added (group B), brown sugar added (group C) and bacteria and brown sugar added (group D), and the water was purified by 24 h biofloc and 12 h circulation. The results showed that at the end of the trial, the biofloc volume in groups B, C, and D was significantly higher than that in the group A (P < 0.05), with group D having a significantly greater biofloc volume than groups B and C (P < 0.05). The volume of biological flocs in group D was significantly higher than that in groups B and C (P < 0.05). The decrease rate of total ammonia nitrogen (TAN) is D > C > B > A, and the decrease rate of TAN in group D (35.9% ± 5%) was significantly higher than that in groups A, B and C (14.2% ± 8%, 11.3% ± 4% and 30.2% ± 5%) (P < 0.05). The concentration of ${\text{NO}}_{\text{2}}^{-}\text{-N}$ increased by 10.1% ± 0.3% in group A, and the decrease rate of ${\text{NO}}_{\text{2}}^{-}\text{-N}$ in group D was 49 ± 10.4%, which was significantly higher than that in groups B and C (11.3% ± 0.2%, 6.4% ± 0.5%) (P < 0.05). The concentrations of TAN and ${\text{NO}}_{\text{2}}^{-}\text{-N}$ in group D were significantly negatively correlated with the volume of biological floc in the first 24 h, and tended to be stable in the later period. During the trial, the concentration of suspended particulate in groups A, B, and C increased slightly, while group D achieved a suspended particulate removal rate of (21.5 ± 3.9)%, significantly higher than the other three groups (P < 0.05). Dissolved oxygen concentration at the end of the trial followed the order of A > B > C > D. All groups experienced a decrease in pH during the trial, and the pH levels in groups B, C, and D were significantly lower than that in the group A at the end of the trial (P < 0.05). These findings suggest that the combination of biofloc formed by B. subtilis and brown sugar with shrimp circulating aquaculture system can achieve balance in the short term and effectively purify TAN, ${\text{NO}}_{\text{2}}^{-}\text{-N}$ , and suspended particulate in aquaculture water.