The Chinese mitten crab (Eriocheir sinensis) is bred extensively in Eastern and Northern China and faces a series of problems such as frequent diseases, germplasm degradation, and declining benefits, which have appeared to seriously affect the sustainable development of the cultivation industry. Haematococcus pluvialis, a type of unicellular green algae, have been proven to be the suitable dietary supplementation in crustacean feeds. After 14 days of feeding with 5% dietary supplementation with Haematococcus pluvialis powder, the growth, antioxidantase activities, and gut microbiota of E. sinensis were analyzed. The results indicated that H. pluvialis powder could significantly improve growth indicators including weight gain rate (WGR) and specific growth rate (SGR) of E. sinensis (p < 0.05). The levels of superoxide dismutase (SOD) and catalase (CAT) declined, while that of phenoloxidase (PO) kept rising under the treatment of H. pluvialis powder. Moreover, alkaline phosphatase (AKP) activity dropped initially and then increased. No significant differences in the Simpson index and Chao1 index in the control and H. pluvialis powder treatment were observed (p > 0.05). Although the dominant microbiota in the crab gut were not affected significantly by H. pluvialis powder, significant differences in the relative abundance of the dominant phyla between the control and H. pluvialis powder treatment groups were observed (p < 0.05). Furthermore, the relative abundance of Firmicutes and Candidatus_Bacilloplasma, which play an important role in the life activities of E. sinensis, were significantly higher in the group treated by H. pluvialis powder than in the control (p < 0.05). Therefore, the H. pluvialis powder could be potentially used not only as a rapid fattening regulator, but also to improve the immunity and metabolic capacity of E. sinensis.

中文翻译：

---

膳食补充雨生红球藻对中华绒螯蟹（Eriocheir sinensis）生长、抗氧化酶活性和肠道微生物群的影响

中华绒螯蟹在我国华东、华北地区广泛养殖，面临病害多发、种质退化、效益下降等一系列问题，已严重影响养殖业的可持续发展。雨生红球藻是一种单细胞绿藻，已被证明是甲壳类饲料中合适的膳食补充剂。饲喂添加 5% 雨生红球藻粉的饲料 14 天后，对中华红球藻的生长、抗氧化酶活性和肠道微生物群进行了分析。结果表明，雨生红球藻粉可以显着提高中华红球藻增重率（WGR）和特定生长率（SGR）等生长指标（p  < 0.05）。雨生红球菌粉处理后，超氧化物歧化酶（SOD）和过氧化氢酶（CAT）水平下降，酚氧化酶（PO）水平不断上升。此外，碱性磷酸酶（AKP）活性先下降后上升。对照和雨生红藻粉处理的 Simpson 指数和 Chao1 指数没有观察到显着差异（p  > 0.05）。尽管雨生红球藻粉对蟹肠道中的优势菌群没有显着影响，但在对照组和雨生红球藻粉处理组之间观察到优势门的相对丰度存在显着差异（ p  < 0.05）。此外，雨生红球藻粉处理组中对中华球虫生命活动起重要作用的厚壁菌门和假丝酵母菌的相对丰度显着高于对照组（p  < 0.05）。因此，雨生红球藻粉不仅可以作为快速育肥调节剂，还可以用于提高中华红球藻的免疫力和代谢能力。