Aquaculture, as one of the largest food production sectors, is a candidate industry to solve the worldwide food shortage. Nitrogenous compounds from uneaten feed and excretion continually destroy the rearing water quality during the breeding which causes slow growth, production reduction, and even death. Thus, alleviating water contamination can improve fish welfare and prevent disease occurrence. In the present study, a stable bacteria-microalgae association was used to construct a biofortified crucian carps culture system without water exchange. During the 8-week experiments, the water quality, fish production, and intestinal health were assessed. In this biofortified system, water quality was significantly improved and the content of total ammonia-N and nitrite-N was finally in a state of dynamic equilibrium at a lower concentration compared with that in blank control. The final body weight of crucian carps in the bacteria-microalgae groups was significantly improved by 10.52%. The crucian carps intestinal health including amylase and lipase activities, villus length and width, and muscle thickness was also significantly increased by 56.33%, 63.89%, 347.25%, 98.48%, and 129.53%, respectively, in bacteria-microalgae groups. Intestinal microbiota was improved significantly by changing the microbiota composition and LEfSe analysis demonstrated that some genera frequently found in the intestines of stressed and dying animals were enriched in crucian carps intestine in blank control. The KEGG prediction proved that metabolisms including carbon metabolism, pyruvate metabolism, and fatty acid metabolism were significantly improved. In summary, the bacteria-microalgae association biofortified culture system improved the rearing water quality, and then improved the intestinal health of crucian carp, eventually increased the production of crucian carp.

水产养殖作为最大的粮食生产部门之一，是解决全球粮食短缺的候选产业。未食用饲料和排泄物中的含氮化合物在养殖过程中不断破坏养殖水质，导致生长缓慢、减产甚至死亡。因此，减轻水污染可以改善鱼类福利并预防疾病的发生。在本研究中，使用稳定的细菌-微藻联合构建了一个无需换水的生物强化鲫鱼养殖系统。在为期 8 周的实验中，评估了水质、鱼类产量和肠道健康。在这个生物强化系统中，与空白对照相比，水质得到明显改善，总氨氮和亚硝酸盐含量最终处于较低浓度的动态平衡状态。菌-微藻组鲫鱼最终体重显着提高10.52%。在细菌-微藻组中，包括淀粉酶和脂肪酶活性、绒毛长度和宽度以及肌肉厚度在内的鲫鱼肠道健康也分别显着增加了 56.33%、63.89%、347.25%、98.48% 和 129.53%。通过改变微生物群组成，肠道微生物群得到显着改善，LEfSe 分析表明，在空白对照的鲫鱼肠道中经常发现的一些属在应激和垂死动物的肠道中富集。KEGG预测证明，包括碳代谢、丙酮酸代谢和脂肪酸代谢在内的代谢得到了显着改善。综上所述，菌-微藻联合生物强化养殖系统改善了养殖水质，进而改善了鲫鱼的肠道健康，最终提高了鲫鱼的产量。