The aim of this study was isolation and characterization of heterotrophic bacteria capable of ammonium and nitrite removal at 15 °C (optimal temperature for growing rainbow trout Oncorhynchus mykiss). Environmental isolates were grown in liquid media containing ammonium or nitrite, and best strains in terms of growth and ammonium or nitrite removal were identified via 16S rRNA sequencing. Dyadobacter sp. (no. 68) and Janthinobacterium sp. (no. 100) were selected for optimal adaptation to growth at 15 °C and best ammonium and nitrite removal (P < 0.05), respectively. A heterotrophic ammonium and nitrite removal (HAN) microbial complex, containing selected strains, was prepared and applied in a trout culture system. After 10 days, the effect of microbial HAN complex was investigated in terms of ammonium and nitrite removal, as well as stress and immune indices present in the plasma of cultivated trout. Compared to a standard cultivation setup, addition of the HAN complex had a clear beneficial effect on keeping the un-ionized ammonia and nitrite level below prescribed standards (P < 0.05). This resulted in reduction of stress and immune reactions of cultivated fish (P < 0.05), leading to an augmentation of final weight and survival. Application of the selected microbial complex resulted in a significant improvement of the aquaculture ecosystem.

这项研究的目的是分离和鉴定能够在15°C（生长虹鳟Oncorhynchus mykiss的最佳温度）下去除铵和亚硝酸盐的异养细菌。环境分离株在含有铵或亚硝酸盐的液体培养基中生长，并通过16S rRNA测序确定了生长和去除铵或亚硝酸盐方面的最佳菌株。杆菌属 （第68号）和Janthinobacterium sp。（第100号）被选择为在15°C下最佳生长适应性和最佳去除铵和亚硝酸盐（P <0.05）。制备了包含选定菌株的异养铵和亚硝酸盐去除（HAN）微生物复合物，并将其应用于鳟鱼培养系统。10天后，根据铵态氮和亚硝酸盐的去除，以及养殖鳟鱼血浆中存在的压力和免疫指数，研究了微生物HAN复合物的作用。与标准栽培设施相比，HAN配合物的添加具有明显的有益效果，可将未电离的氨和亚硝酸盐水平保持在规定的标准以下（P  <0.05）。这样可以减少养殖鱼类的压力和免疫反应（P <0.05），导致最终体重和生存期的增加。所选微生物复合物的应用显着改善了水产养殖生态系统。