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尝试在养殖中期逐渐降低碳源添加量至零,探讨驯化硝化型生物絮体对生物絮凝高密度南美白对虾养殖系统的水质、生物絮体细菌群落动态变化和对虾生长性能的影响。实验在3个跑道式养殖系统中进行,放养密度均为685尾/m~3。水质结果表明养殖前1~45 d,每日按日投饵量的100%~150%添加葡萄糖,能很好地降低氨氮的浓度,但对亚硝酸盐氮处理效果不明显。投糖量下降至零后,氨氮仍能维持在较低水平,亚硝酸盐氮浓度明显下降。利用高通量测序技术对生物絮体的细菌群落结构进行分析。检测结果表明在门水平上,异养型和硝化型生物絮体的主要优势菌群都是Proteobacteria(变形菌门)和Bacteroidetes(拟杆菌门)。在纲水平上,异养型生物絮体的优势菌群是Alphaproteobacteria(α-变形菌纲),而硝化型生物絮体的优势菌群有Alphaproteobacteria(α-变形菌纲)、Flavobacteria(黄杆菌纲)和Gammaproteobacteria(γ-变形纲)。系统在65 d后不添加碳源情况下,生物絮体的异养细菌丰度减少,硝化螺旋菌属(Nitrospiral)开始快速增多并发展成为硝化细菌的优势菌群属,异养型生物絮体逐渐转变为硝化型生物絮体。实验结束时,总投糖量占总投饵量的41.03%±7.86%。南美白对虾的存活率和产量分别为43.35%±7.57%和(3.03±0.59)kg/m3。研究表明驯化硝化型生物絮体能优化高密度零水交换对虾养殖系统生物絮体的细菌群落结构和丰度,改善养殖水环境,保证对虾的生长和存活,节约成本。
Try to reduce the amount of carbon source added to zero gradually in the mid-breeding period to discuss the effects of acclimated nitrifying bioflocs on the water quality of bioflocculation and bacterial community dynamics and shrimp growth performance of P. vannamei culture system. Experiments were carried out in three runway breeding systems, and the stocking density was 685 / m ~ 3. The results of water quality showed that 1 ~ 45 days before breeding, the daily addition of glucose by 100% ~ 150% of the daily feeding amount could well reduce the concentration of ammonia nitrogen, but the effect of nitrite nitrogen treatment was not obvious. When the sugar content dropped to zero, ammonia nitrogen remained at a low level, and the nitrite nitrogen concentration dropped significantly. The bacterial community structure of bioflocs was analyzed by high-throughput sequencing. The results showed that Proteobacteria and Bacteroidetes were the main dominant bacteria in heterotrophic and nitrifying bioflocs at the gate level. At the level of the outline, the heterotrophic biofloc is the dominant microflora of Alphaproteobacteria (Alpha-Proteobacteria), while the dominant microflora of nitrifying bioflocs is Alphaproteobacteria (Alpha-Proteobacteria), Flavobacteria ) And Gammaproteobacteria (Gamma-deformable). In the system without adding carbon source after 65 days, the abundance of heterotrophic bacteria in biological flocs decreased, Nitrospiral began to rapidly increase and became the dominant bacteria group of nitrifying bacteria, heterotrophic bioflocs Gradually transformed into nitrifying biological floc. At the end of the experiment, the total sugar content accounted for 41.03% ± 7.86% of the total feed. The survival rate and yield of P. vannamei were 43.35% ± 7.57% and 3.03 ± 0.59 kg / m3, respectively. Studies have shown that domesticated nitrifying bioflocs can optimize the bacterial community structure and abundance of biological flocs in high density zero water exchange shrimp farming system, improve the aquaculture water environment, ensure the growth and survival of shrimp, and save costs.