Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, Ocean University of China, Qingdao, 266003, PR China; Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003, China.
Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, Ocean University of China, Qingdao, 266003, PR China; Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
Fish Shellfish Immunol. 2020 May;100:261-271. doi: 10.1016/j.fsi.2020.02.070. Epub 2020 Mar 3.
Fermentation has been reported to improve the utilization of plant ingredients including soybean meal (SBM) by fish, but the detailed mechanism is still poorly understood. This study compared the effects of partial replacement of fish meal (FM) protein with SBM or Enterococcus faecium fermented SBM (EFSM) on the growth, antioxidant status, intestinal microbiota, morphology, and inflammatory responses in turbot (Scophthalmus maximus L.). The FM-based diet was used as the control (CONT). Two experimental diets were formulated in which 45% of the FM protein was replaced with SBM or EFSM. Each diet was fed to triplicate groups of fish (7.57 ± 0.01 g) twice daily for 79 d. Inferior growth performance was observed in SBM group, however, no significant depression was observed in EFSM group compared to the CONT group. The CONT group had the highest values of lysozyme, complement component 3, total antioxidant capacity, superoxide dismutase and catalase, followed by the EFSM group, and the lowest in SBM group. The malondialdehyde content was lowest in the CONT group, followed by the EFSM group, and was highest in the SBM group. Gut morphology showed that SBM diet induced alterations typical for intestinal inflammation including decreased villus and microvillus height, and increased width and inflammatory cell infiltration of the lamina propria. However, the EFSM group alleviated such SBM-induced intestinal pathological disruption. Paralleled with the morphological symptoms, the inflammatory gene expression levels of tumor necrosis factor alpha, interleukin-1 beta and interleukin-8 were highest in the SBM group, followed by the EFSM group, and were lowest in the CONT group. Furthermore, the intestinal microbiota analysis revealed that EFSM group had an overall more similar microbiota with CONT group than SBM group. Specifically, compared with the SBM group, EFSM group significantly enhanced the probiotics Lactobacillus and anti-inflammatory bacterium Faecalibaculum, and inhibited the Vibrio. Collectively, this study indicated that Enterococcus faecium fermentation effectively counteracted the negative effects of SBM by enhancing antioxidant capacity, suppressing inflammatory responses, and modulating gut microbiota in turbot.
发酵已被报道可改善鱼类对植物成分（包括豆粕[SBM]）的利用，但详细机制仍知之甚少。本研究比较了用 SBM 或屎肠球菌发酵 SBM（EFSM）部分替代鱼粉（FM）蛋白对大菱鲆（Scophthalmus maximus L.）生长、抗氧化状态、肠道微生物群、形态和炎症反应的影响。FM 基础日粮用作对照（CONT）。设计了两种实验日粮，其中 45%的 FM 蛋白被 SBM 或 EFSM 替代。每种日粮以 7.57±0.01g 的重量投喂给 3 组重复的鱼，每天投喂 2 次，共 79d。SBM 组的生长性能较差，而 EFSM 组与 CONT 组相比没有明显的下降。CONT 组的溶菌酶、补体成分 3、总抗氧化能力、超氧化物歧化酶和过氧化氢酶活性最高，其次是 EFSM 组，SBM 组最低。CONT 组的丙二醛含量最低，其次是 EFSM 组，SBM 组最高。肠道形态显示 SBM 日粮诱导了典型的肠道炎症变化，包括绒毛和微绒毛高度降低，固有层宽度增加和炎症细胞浸润。然而，EFSM 组缓解了 SBM 引起的这种肠道病理破坏。与形态症状平行的是，SBM 组肿瘤坏死因子-α、白细胞介素-1β和白细胞介素-8 的炎症基因表达水平最高，其次是 EFSM 组，CONT 组最低。此外，肠道微生物组分析显示，EFSM 组与 CONT 组的微生物组总体更为相似，而与 SBM 组差异较大。具体而言，与 SBM 组相比，EFSM 组显著增强了益生菌乳酸杆菌和抗炎菌粪肠球菌，抑制了弧菌。综上所述，本研究表明屎肠球菌发酵通过增强抗氧化能力、抑制炎症反应和调节大菱鲆肠道微生物群，有效抵消了 SBM 的负面影响。
