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In order to study the optimal use of Lactobacillus plantarum in sea cucumber (Apostichopus japonicus), 49 days feeding trial was conducted to determine the influence of immersion bathing in different concentrations of Lactobacillus plantarum CLY-05 on body weight gain rate and non-specific immune activities. The potential effect of CLY-05 on gut microbiota was also analyzed during the immersion bathing at the optimum concentration. The results showed that the body weight growth rate of all bathing groups was higher than that of control. The highest specific growth rate (4.58%) and weight gain rate (25.35%) was achieved at the bacterial concentration of 1×103 CFU/mL. The activities of non-specific immune enzymes (ACP, AKP, SOD and LZM) of all bathing groups increased after immersion bathing, and the enzyme activities of groups bathed with the bacterium at 1×103 and 1×104 CFU/mL reached the highest. Therefore, 1×103 CFU/mL was considered as the optimum concentration of L. plantarum CLY-05 for A. japonicus pond culture. The results of gut microbiota analysis showed that the gut microbiota changed with the addition of L. plantarum CLY-05, and the richness and diversity of the gut microbiota peaked on day 14 and day 21, respectively. The correlation analysis revealed that the non-specific immune enzyme activities were significantly correlated to some gut bacteria (in the phyla Proteobacteria, Firmicutes) after immersion bathing in L. plantarum CLY-05. These findings provide the theoretical foundation for probiotic application in sea cucumber farming.

为探究植物乳杆菌（Lactobacillus plantarum）在仿刺参（Apostichopus japonicus）中的最优应用方案，本研究开展了为期49天的养殖试验，分析不同浓度植物乳杆菌CLY-05浸浴处理对仿刺参体重增长率与非特异性免疫活性的影响。同时，本研究针对最优浓度下的浸浴处理，进一步解析了CLY-05对仿刺参肠道菌群的潜在调控效应。
试验结果表明：所有浸浴组的体重生长速率均显著高于对照组。当菌液浓度为1×10³ CFU/mL时，仿刺参的比生长速率（4.58%）与体重增长率（25.35%）均达到最高水平。
经浸浴处理后，所有浸浴组的非特异性免疫酶（酸性磷酸酶ACP、碱性磷酸酶AKP、超氧化物歧化酶SOD及溶菌酶LZM）活性均有所提升；其中，1×10³ CFU/mL与1×10⁴ CFU/mL浓度组的酶活性达到峰值。
综上，1×10³ CFU/mL被确定为仿刺参池塘养殖中植物乳杆菌CLY-05的最优浸浴浓度。
肠道菌群分析结果显示：施加植物乳杆菌CLY-05后，仿刺参肠道菌群结构发生显著改变，其菌群丰富度与多样性分别在试验第14天与第21天达到峰值。
相关性分析结果揭示：经植物乳杆菌CLY-05浸浴处理后，仿刺参的非特异性免疫酶活性与部分肠道菌群（隶属于变形菌门Proteobacteria、厚壁菌门Firmicutes）存在显著相关性。
本研究结果为益生剂在刺参养殖产业中的应用提供了理论支撑。