Department of Wildlife and Fisheries Sciences, Texas A&M University System, College Station, TX, 77843-2258, USA.
Department of Wildlife and Fisheries Sciences, Texas A&M University System, College Station, TX, 77843-2258, USA; Key Laboratory of Applied Marine Biotechnology, Ministry of Education, Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo, 315211, PR China.
Fish Shellfish Immunol. 2018 Jun;77:273-279. doi: 10.1016/j.fsi.2018.04.003. Epub 2018 Apr 3.
To reduce susceptibility to stressors and diseases, immune-modulators such as β-glucans have been proven effective tools to enhance the innate immune responses of fish. Consequently, commercial sources of this polysaccharide are becoming increasingly more available. Algamune™ is a commercial additive produced from Euglena gracilis, as a source of linear β-1,3-glucan. In order to evaluate the immunomodulatory effects of this β-glucan product, the present study assessed the innate immune parameters of red drum (Sciaenops ocellatus) exposed to Algamune™ ex vivo and in vivo. Isolated kidney phagocytes were incubated with graded concentrations (0, 0.2, 0.4, 0.8, 1.6 and 3.2 mg L) of dried Euglena gracilis (Algamune™) as well as purified Paramylon (linear β-1,3 glucan). Increased bactericidal activity against Streptococcus iniae, and production of intracellular O anion superoxide were stimulated by both β-glucan sources. A reduced activity of extracellular anion superoxide was observed by the phagocytes incubated with Algamune ™. After corroborating the effectiveness of the glucan source ex vivo, a feeding trial was conducted using red drum juveniles (∼26.6 g initial weight). Fish were fed diets with graded levels of Algamune™ (0, 100, 200, 400 and 800 mg kg) twice daily for 21 days. No significant differences were detected regarding production performance parameters. At the end of the feeding trial, blood, intestinal content, and kidney were sampled. Intestinal microbiota from fecal material was analyzed through denaturing gradient gel electrophoresis (DGGE) and found to be similar among all treatments. No significant differences were detected for oxidative radical production from whole blood, and isolated phagocytes, and plasma lysozyme activity. However, the total hemolytic activity of red drum plasma was increased in fish fed 100 and 200 mg kg of dietary Algamune™ when compared to fish fed the basal diet. Based on results from both ex vivo and in vivo trials, β-glucan from Algamune™ was demonstrated to have a moderate immunostimulatory effects on red drum.
为了降低鱼类对压力源和疾病的易感性，免疫调节剂如β-葡聚糖已被证明是增强鱼类先天免疫反应的有效工具。因此，这种多糖的商业来源越来越多。Algamune™是一种从绿眼虫（Euglena gracilis）中提取的商业添加剂，作为线性β-1,3-葡聚糖的来源。为了评估这种β-葡聚糖产品的免疫调节作用，本研究评估了暴露于 Algamune™的红鼓鱼（Sciaenops ocellatus）的先天免疫参数，体外和体内。分离的肾吞噬细胞与梯度浓度（0、0.2、0.4、0.8、1.6 和 3.2mg/L）的干燥绿眼虫（Algamune™）以及纯化的 Paramylon（线性β-1,3 葡聚糖）孵育。两种β-葡聚糖来源均刺激了对杀鲑气单胞菌的杀菌活性和细胞内 O 阴离子超氧化物的产生。用 Algamune ™孵育的吞噬细胞观察到细胞外阴离子超氧化物的活性降低。在证实了葡聚糖来源的有效性后，进行了一项使用红鼓鱼幼鱼（初始重量约 26.6g）的饲养试验。鱼每天两次喂食含有梯度水平 Algamune™（0、100、200、400 和 800mg/kg）的饮食 21 天。未检测到生产性能参数的显著差异。在饲养试验结束时，采集血液、肠道内容物和肾脏。通过变性梯度凝胶电泳（DGGE）分析粪便材料中的肠道微生物群，发现所有处理之间相似。全血、分离的吞噬细胞和血浆溶菌酶活性的氧化自由基产生没有差异。然而，与基础饮食相比，喂食 100 和 200mg/kg 日粮 Algamune™的鱼的红鼓鱼血浆总溶血活性增加。基于体外和体内试验的结果，Algamune™的β-葡聚糖被证明对红鼓鱼具有适度的免疫刺激作用。
