Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), College of Animal Science and Technology, Southwest University, Chongqing 400715, PR China.
Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), College of Animal Science and Technology, Southwest University, Chongqing 400715, PR China.
Fish Shellfish Immunol. 2020 Aug;103:135-142. doi: 10.1016/j.fsi.2020.04.070. Epub 2020 May 11.
This study is aimed at identifying the effects of dietary fiber on gut health, as well as the association between that understanding and fiber consumption in fish. A total of 300 juvenile largemouth bass (micropterus salmoides, initial average weight: 15.38 ± 0.16g) were randomly divided into three treatment groups (4 replicates per group). Fish were fed with isoproteic and isolipidic diets containing 0% (low fiber, LF), 4% (moderate fiber, MF) and 8% (high fiber, HF) soybean fiber, respectively. The intestine and intestinal content of test fish per treatment group after 56 days of treatment were sampled. The results showed that the anterior intestinal sections had normal histological architecture, and no considerable damage or inflammation was observed in any histological section from all subjects examined. Curiously, fish fed the MF diet had better histological alterations than the other treatments. Meanwhile, the intestinal antioxidant capacity in the MF group was significantly promoted when compared to the other groups, as well as up-regulated expression of antioxidant-related genes including sod, cat and gp with increasing dietary fiber concentrations. Importantly, the administrations of MF diet remarkably elevated largemouth bass innate immune parameters include intestinal inducible nitric oxide synthase (iNOS) activity, nitric oxide (NO) and total protein content. Similarly, dietary administrations of fiber down-regulated notablely the expression of pro-inflammatory cytokines including IL-8, IL-1β and TNFα, whereas up-regulated tolerogenic cytokine IL-10 and TGF-β1 mRNA levels. In addition, dietary fibers also modulated the community structure of the intestinal microbiota by significantly altering bacterial diversity. Dietary supplemental fibers regulated intestinal microbiota in largemouth bass, characterized by a reduced abundance of Fusobacteria along with increased abundances of Proteobacteria and Firmicutes. Taken together, the present results suggested that moderate fiber supplementation was beneficial to promoting intestinal health status of fish through antioxidant and anti-inflammatory effects, which could be at least partially responsible by the modulation of gut microbial composition.
本研究旨在确定膳食纤维对肠道健康的影响，以及对这种理解与鱼类膳食纤维摄入之间的关联。共选择 300 尾幼龄大口黑鲈（Micropterus salmoides，初始平均体重：15.38±0.16g）随机分为 3 个处理组（每组 4 个重复）。用分别含有 0%（低纤维，LF）、4%（中纤维，MF）和 8%（高纤维，HF）大豆纤维的等蛋白和等脂饮食喂养鱼类。对每个处理组的试验鱼的肠段和肠内容物进行取样。结果表明，前肠段具有正常的组织学结构，在所有检查的组织切片中，没有观察到任何明显的损伤或炎症。有趣的是，MF 组的组织学变化优于其他处理组。同时，与其他组相比，MF 组的肠道抗氧化能力显著增强，随着膳食纤维浓度的增加，抗氧化相关基因 sod、cat 和 gp 的表达也上调。重要的是，MF 组饮食显著提高了大口黑鲈的固有免疫参数，包括肠道诱导型一氧化氮合酶（iNOS）活性、一氧化氮（NO）和总蛋白含量。同样，膳食纤维的饮食给药也显著下调了包括 IL-8、IL-1β 和 TNFα 在内的促炎细胞因子的表达，而上调了耐受细胞因子 IL-10 和 TGF-β1 的 mRNA 水平。此外，膳食纤维还通过显著改变细菌多样性来调节肠道微生物群落结构。膳食纤维调节大口黑鲈的肠道微生物群，特征是厚壁菌门丰度降低，变形菌门和厚壁菌门丰度增加。综上所述，本研究结果表明，通过抗氧化和抗炎作用，中等纤维补充对鱼类肠道健康有益，这至少部分归因于肠道微生物组成的调节。
