College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, PR China.
College of Fisheries, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, PR China.
Fish Shellfish Immunol. 2020 Sep;104:202-212. doi: 10.1016/j.fsi.2020.05.079. Epub 2020 Jun 3.
The present study was conducted to evaluate the effects of marine polysaccharides from seaweed Enteromorpha on growth performance, immune responses, intestinal morphology and microbial community in the banana shrimp Fenneropenaeus merguiensis. Two thousand and four hundred juvenile shrimps with an average body weight of 2.18 ± 0.06 g were fed for 42 d with diets containing different levels of Enteromorpha polysaccharides (EPS): 0 (control), 1, 2 and 3 g/kg as treatment groups, each of group was replicated three times with two hundred shrimps per replicate. Dietary supplementation of 1 g/kg EPS showed a consistent improvement in the final weight, weight gain, average daily gain rate (ADGR) and specific growth rate (SGR) (P < 0.05), while showed a decrease in the feed conversion ratio (FCR) of shrimp (P < 0.05). Besides, the total anti-oxidative capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), lysozyme (Lyz), alkaline phosphatase (ALP), and phenoloxidase (PO) activities in hemolymph were enhanced by dietary supplementation of 1 g/kg EPS (P < 0.05), while it reduced the hemolymph MDA content (P < 0.05). Shrimp fed 1 g/kg EPS supplemented diets up-regulated FmLyz, FmSOD5 and FmCLAP gene expression level of hepatopancreas and gill (P < 0.05), and also improved the intestinal FmLC2, FmLyz, FmSOD5 and FmCLAP gene expression levels (P < 0.05). In addition, shrimp fed diets containing 1 g/kg EPS increased the villus width (P < 0.05) and resulted in a higher villus surface area (P < 0.05). According to 16S rRNA sequencing results, dietary supplementation of 1 g/kg EPS tended to increase the relative abundance of Firmicutes at phylum level (P = 0.07) and decrease the relative abundance of Vibrio at genus level (P = 0.08). There was a significant positive correlation between the relative abundance of Firmicutes and mRNA expression of intestinal immune-related genes (P < 0.05). These findings revealed that dietary 1 g/kg EPS could improve growth performance, enhance nonspecific immunity and modulate intestinal function of banana shrimp F. merguiensis.
本研究旨在评估海藻浒苔多糖对斑节对虾生长性能、免疫反应、肠道形态和微生物群落的影响。将 2400 尾平均体重为 2.18±0.06g 的幼虾用含有不同水平浒苔多糖（EPS）的饲料喂养 42 天：0（对照）、1、2 和 3g/kg 作为处理组，每组重复 3 次，每次 200 尾。结果表明，饲料中添加 1g/kg EPS 可持续提高终重、增重、平均日增重率（ADGR）和特定生长率（SGR）（P<0.05），同时降低虾的饲料转化率（FCR）（P<0.05）。此外，添加 1g/kg EPS 可提高血淋巴总抗氧化能力（T-AOC）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GPx）、谷胱甘肽 S-转移酶（GST）、溶菌酶（Lyz）、碱性磷酸酶（ALP）和酚氧化酶（PO）活性（P<0.05），同时降低血淋巴 MDA 含量（P<0.05）。添加 1g/kg EPS 的饲料可上调肝胰腺和鳃 FmLyz、FmSOD5 和 FmCLAP 基因表达水平（P<0.05），并改善肠道 FmLC2、FmLyz、FmSOD5 和 FmCLAP 基因表达水平（P<0.05）。此外，添加 1g/kg EPS 的饲料可增加虾的肠绒毛宽度（P<0.05），提高绒毛表面积（P<0.05）。根据 16S rRNA 测序结果，添加 1g/kg EPS 可增加厚壁菌门的相对丰度（P=0.07），降低弧菌属的相对丰度（P=0.08）。肠道免疫相关基因的相对丰度与厚壁菌门呈显著正相关（P<0.05）。这些发现表明，饲料中添加 1g/kg EPS 可提高斑节对虾的生长性能，增强非特异性免疫，调节肠道功能。
