Dong Jinghao, Ma Hailong, Liu Kuimei, Zhou Wei, Liu Suya, Sun Yongjun, Ju Wenming, Wang Shanshan
Rongcheng Campus, Harbin University of Science and Technology, Weihai, Shandong, China.
Rongcheng Hongde Marine Biotechnology Co., Ltd., Weihai, Shandong, China.
PeerJ. 2025 Aug 19;13:e19944. doi: 10.7717/peerj.19944. eCollection 2025.
Brown algae polysaccharides (BAPs), derived from marine brown algae, represent bioactive macromolecules with potential functional feed applications as novel feed additives for improving the health and nutritional quality of aquatic animals. Previous studies have shown that BAPs possess antioxidant, anti-inflammatory, immunomodulatory, antimicrobial, and antiviral activities. BAPs extracted from (UPS) contain kinds of BAPs such as alginate, mannitol, fucoidan and fucoheterosaccharides but there are few studies on the combined effects of these BAPs.
This study investigated the effects of UPS by supplementing juvenile sea cucumbers with 0%, 0.5%, 1%, 1.5%, 2%, and 3% UPS (polysaccharide/sea cucumber biomass, W/W). After 60 days feeding, the nutritional composition of body wall, digestive capacity and immune performance were analyzed. The diversity of intestinal microbiota in sea cucumber was analyzed using 16S rRNA gene sequence amplification technology to elucidate the effects of UPS supplementation on the composition and function of intestinal microorganisms.
It was demonstrated that UPS supplementation significantly increased the nutritional content of the juvenile sea cucumber body wall although growth performance remained unchanged. The polysaccharide content peaked at 1% supplementation of UPS, which was 1.6-fold higher than that of the control group. Moreover, UPS also enhanced intestinal digestive enzyme activity such as cellulase or lipase activity, which was maximized at 1% or 3% supplementation with 5.8-fold and 1.6-fold higher than that of the control group. Additionally, UPS could improve immune performance of juvenile sea cucumber by significantly elevating superoxide dismutase activity (T-SOD). It was worth noting that low UPS concentrations (1% and 1.5%) reduced malondialdehyde (MDA) content while high concentrations (2% and 3%) increased it, indicating that low UPS supplementation may had a better effect on immune performance. 16S rRNA gene sequencing revealed that UPS supplementation reduced pathogenic populations. Function analysis showd that UPS may modulate metabolic pathways related to nitrotoluene and carbon source utilization. In summary, -derived BAP especially at low concentrations (1%) could enhance the nutritional composition, digestive and immune functions, and intestinal microbial community and metabolic profiles of juvenile sea cucumber. These findings provide a preliminary theoretical foundation for applying polysaccharides in aquaculture practices for sea cucumbers and other marine species.
褐藻多糖（BAPs）源自海洋褐藻，是具有潜在功能的生物活性大分子，有望作为新型饲料添加剂应用于水产养殖，以改善水生动物的健康状况和营养品质。先前的研究表明，BAPs具有抗氧化、抗炎、免疫调节、抗菌和抗病毒活性。从[具体褐藻]中提取的褐藻多糖（UPS）含有多种BAPs，如藻酸盐、甘露醇、岩藻聚糖和岩藻杂聚糖，但关于这些BAPs联合作用的研究较少。
本研究通过在幼参饲料中添加0%、0.5%、1%、1.5%、2%和3%的UPS（多糖/海参生物量，W/W）来研究UPS的作用效果。投喂60天后，分析体壁的营养成分、消化能力和免疫性能。利用16S rRNA基因序列扩增技术分析海参肠道微生物群的多样性，以阐明添加UPS对肠道微生物组成和功能的影响。
结果表明，添加UPS显著提高了幼参体壁的营养成分含量，尽管生长性能未发生变化。多糖含量在添加1%的UPS时达到峰值，比对照组高1.6倍。此外，UPS还增强了肠道消化酶活性，如纤维素酶或脂肪酶活性，在添加1%或3%时达到最大值，分别比对照组高5.8倍和1.6倍。此外，UPS可通过显著提高超氧化物歧化酶活性（T-SOD）来改善幼参的免疫性能。值得注意的是，低浓度的UPS（1%和1.5%）降低了丙二醛（MDA）含量，而高浓度（2%和3%）则增加了MDA含量，这表明低剂量添加UPS可能对免疫性能有更好的效果。16S rRNA基因测序显示，添加UPS减少了致病菌群。功能分析表明，UPS可能调节与硝基甲苯和碳源利用相关的代谢途径。总之，[具体褐藻]来源的BAPs，尤其是低浓度（1%）时，可增强幼参的营养成分、消化和免疫功能，以及肠道微生物群落和代谢谱。这些发现为多糖在海参及其他海洋物种的水产养殖实践中的应用提供了初步的理论基础。
