Lieke Thora, Stejskal Vlastimil, Behrens Sascha, Steinberg Christian E W, Meinelt Thomas
Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Institute of Aquaculture and Protection of Waters, University of South Bohemia, České Budějovice, Czech Republic.
Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Institute of Aquaculture and Protection of Waters, University of South Bohemia, České Budějovice, Czech Republic.
J Hazard Mater. 2024 Apr 5;467:133737. doi: 10.1016/j.jhazmat.2024.133737. Epub 2024 Feb 8.
This is the first study determining the effects of bath exposure to fulvic acid, a humic substance, on the skin mucosal immunity of rainbow trout (Oncorhynchus mykiss). Humic substances have recently been gaining attention for their increasing concentrations in aquatic ecosystems and their use as supplements in sustainable aquaculture. This study demonstrated that water exposure to fulvic acid at concentrations of 5 mg C/L and 50 mg C/L increased lysozyme and alkaline phosphatase activities in the mucus by approximately 2-fold and 2.5 to 3.2-fold, respectively. Furthermore, exposure to 50 mg C/L resulted in a 77.0% increase in mucosal immunoglobulin concentrations compared to the other groups. Importantly, all mucus samples demonstrated significant antibacterial activity against Yersinia ruckeri, with control mucus reducing bacterial growth by 44.5% and exposure to fulvic acid increasing this effect to 26.3%. Although these modulations show promise for application in aquaculture, alterations of the beneficial microbiota from long-term exposure in natural waters can be expected. Monitoring the rising concentrations of humic substances in natural water bodies is therefore urgently needed. Overall, this study represents the first investigation revealing the ability of humic substances to modulate skin mucosal immunity and the capacity to combat microorganisms.
这是第一项确定接触腐殖酸（一种腐殖质）对虹鳟（Oncorhynchus mykiss）皮肤黏膜免疫影响的研究。腐殖质最近因其在水生生态系统中的浓度不断增加以及作为可持续水产养殖中的补充剂而受到关注。这项研究表明，暴露于浓度为5毫克碳/升和50毫克碳/升的腐殖酸水中，黏液中的溶菌酶和碱性磷酸酶活性分别增加了约2倍和2.5至3.2倍。此外，与其他组相比，暴露于50毫克碳/升导致黏膜免疫球蛋白浓度增加了77.0%。重要的是，所有黏液样本对鲁氏耶尔森菌均表现出显著的抗菌活性，对照黏液使细菌生长减少了44.5%，而暴露于腐殖酸使这种效果提高到了26.3%。尽管这些调节作用显示出在水产养殖中的应用前景，但长期暴露于天然水体中可能会导致有益微生物群的改变。因此，迫切需要监测天然水体中腐殖质浓度的上升。总体而言，这项研究是首次揭示腐殖质调节皮肤黏膜免疫和对抗微生物能力的调查。
