Abstract: Water quality is crucial for Apostichopus japonicas farming and may affect its growth and physiological functions. The accumulation of residual bait and feces usually leads to turbidity and high concentration of solid particles in aquaculture water, resulting in nutrient accumulation and frequent disease outbreaks. This poses a huge threat to the A. japonicas farming industry. Therefore, this study aims to explore the effects of different feed binders on water quality, growth and intestinal microbiota of A. japonicus in recirculating aquaculture system (RAS). Five groups were set up, including no binder group and four groups with added 5% sweet potato starch, xanthan gum, guar gum and carrageenan respectively. A. japonicus weighing 20.0 ± 5.0g were used for researching. Each group had three replicates and the experiment last for 42 days. Kruskal-Wallis rank sum test was used to analyze the difference of intestinal microbiota between groups. Redundancy analysis (RDA) and Canonical correlation analysis (CCA) were used to investigate the relationship between water quality and intestinal microbiota of A. japonicus. The results showed that adding binders improved water quality well, with the guar gum group would give a better result. The concentrations of ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3--N) and total nitrogen (TN) in guar gum group were the lowest at the end of the experiment, and fluctuated less during the experiment. The specific growth rate and feed conversion rate of A. japonicus in sweet potato starch and guar gum groups were significantly higher than that in other groups (P<0.05) and the skin exfoliation rate (RSER) were increased in both groups. The dominant intestinal microbial of cultivation were Proteobacteria. Vibrionaceae and Rhodobacteraceae were the dominant family. And there was significantly different in intestinal microbiota among the groups. The sweet potato starch group had the highest intestinal microbial richness and diversity, while the lowest in the xanthan gum group. The results of significance difference test between groups showed that the feed with added sweet potato starch increased the abundance of beneficial bacteria of A. japonicus, such as Flavobacteriaceae. There was significant correlation between water quality and intestinal microbiota of A. japonicus (P<0.05). At the phylum level, NH4+-N, nitrite nitrogen (NO2--N), NO3--N were negatively correlated with Firmicutes, Actinobacteriota and Bacteroidota. However, the above phyla were positively correlated with Verrucomicrobia and Proteobacteria. At the family level, NH4+-N、NO2--N、NO3--N were positively correlated with Vibrionaceae and Shewanellaceae, while negatively correlated with Flavobacteriaceae and Enterobacteriaceae. Considering the water quality, growth and intestinal microbial of A. japonicus, sweet potato starch and guar gum as feed binder were more conducive to healthy culture of A. japonicus and maintenance the water treatment) in RAS.

Key words: Apostichopus japonicus, feed, binder, recirculating aquaculture system, water quality, growth, intestinal microbiota

摘要： 为探究刺参（Apostichopus japonicus）循环水养殖系统中不同饲料粘合剂对系统水质以及刺参生长和肠道微生物的影响，设置了无粘合剂添加的对照组（D1组）和分别添加5%红薯淀粉（D2）、黄原胶（D3）、瓜尔胶（D4）、卡拉胶（D5）的4个处理组，每组设3个重复。采用（20.0 ± 5.0）g规格的刺参，在刺参循环水养殖系统中饲养42 d，测定了养殖水质、刺参体质量变化和肠道微生物组成，并运用Kruskal-Wallis秩和检验对刺参肠道微生物进行组间差异显著性分析，采用冗余分析和典型关联分析对水质与肠道微生物进行相关性研究。结果显示：粘合剂的添加对水质有优化作用，其中瓜尔胶组水质最佳；红薯淀粉和瓜尔胶组的刺参特定生长率和饲料转化率显著高于其他组（P<0.05），且刺参出皮率提高。刺参肠道优势菌门为变形菌门，拟杆菌门等，优势菌科为弧菌科、红杆菌科等；红薯淀粉组的刺参肠道微生物丰富度和多样性最高，且肠道中黄杆菌科等有益菌丰度升高。水质与刺参肠道微生物存在显著相关性，在科水平上，氨氮、亚硝酸盐氮、硝酸盐氮与弧菌科、希瓦氏菌科呈正相关，与黄杆菌科、肠杆菌科呈负相关。研究表明：综合考虑水质、刺参生长及肠道微生物情况，在刺参饲料中选择红薯淀粉或瓜尔胶作为粘合剂，更有利于刺参的健康养殖及循环水养殖系统中良好水质的维持。

关键词: 刺参, 饲料, 粘合剂, 循环水养殖, 水质, 生长, 肠道微生物