Chen Yuanxin, Jiang Weidan, Wu Pei, Liu Yang, Ma Yaobin, Ren Hongmei, Jin Xiaowan, Jiang Jun, Zhang Ruinan, Li Hua, Feng Lin, Zhou Xiaoqiu
Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China.
J Anim Sci Biotechnol. 2025 Jul 19;16(1):103. doi: 10.1186/s40104-025-01224-7.
Cetobacterium somerae, a symbiotic microorganism resident in various fish intestines, is recognized for its beneficial effects on fish gut health. However, the mechanisms underlying the effects of C. somerae on gut health remain unclear. In this experiment, we investigated the influence of C. somerae (CGMCC No.28843) on the growth performance, intestinal digestive and absorptive capacity, and intestinal structural integrity of juvenile grass carp (Ctenopharyngodon idella) and explored its potential mechanisms.
A cohort of 2,160 juvenile grass carp with an initial mean body weight of 11.30 ± 0.01 g were randomly allocated into 6 treatment groups, each comprising 6 replicates (60 fish per replicate). The experimental diets were supplemented with C. somerae at graded levels of 0.00 (control), 0.68 × 10⁹, 1.35 × 10⁹, 2.04 × 10⁹, 2.70 × 10⁹, and 3.40 × 10⁹ cells/kg feed. Following a 10-week experimental period, biological samples were collected for subsequent analyses.
Dietary supplementation with C. somerae at 1.35 × 10⁹ cells/kg significantly enhanced growth performance, intestinal development, and nutrient retention rate in juvenile grass carp (P < 0.05). The treatment resulted in increased intestinal acetic acid concentration and enhanced activities of digestive enzymes and brush border enzymes (P < 0.05). Furthermore, it reduced intestinal permeability (P < 0.05), preserved tight junctions (TJ) ultrastructural integrity, and increased the expression of TJ and adherens junctions (AJ) biomarkers at both protein and transcriptional levels (P < 0.05). Mechanistically, these effects may be correlated with enhanced antioxidant capacity and coordinated modulation of the RhoA/ROCK, Sirt1, and PI3K/AKT signaling pathways. The appropriate supplementation levels, based on weight gain rate, feed conversion ratio, the activity of serum diamine oxidase and the content of lipopolysaccharide, were 1.27 × 10⁹, 1.27 × 10⁹, 1.34 × 10⁹ and 1.34 × 10⁹ cells/kg, respectively.
C. somerae improved intestinal digestive and absorptive capacity of juvenile grass carp, maintained intestinal structural integrity, and thus promoted their growth and development. This work demonstrates the potential of C. somerae as a probiotic for aquatic animals and provides a theoretical basis for its utilization in aquaculture.
索氏栖热放线菌是一种存在于多种鱼类肠道中的共生微生物，因其对鱼类肠道健康的有益作用而受到认可。然而，索氏栖热放线菌对肠道健康产生影响的潜在机制仍不清楚。在本实验中，我们研究了索氏栖热放线菌（CGMCC No.28843）对草鱼幼鱼（Ctenopharyngodon idella）生长性能、肠道消化吸收能力和肠道结构完整性的影响，并探讨了其潜在机制。
将2160尾初始平均体重为11.30±0.01 g的草鱼幼鱼随机分为6个处理组，每组6个重复（每个重复60尾鱼）。实验饲料中分别添加0.00（对照）、0.68×10⁹、1.35×10⁹、2.04×10⁹、2.70×10⁹和3.40×10⁹个细胞/kg饲料水平的索氏栖热放线菌。经过10周的实验期后，采集生物样本进行后续分析。
饲料中添加1.35×10⁹个细胞/kg的索氏栖热放线菌显著提高了草鱼幼鱼的生长性能、肠道发育和营养保留率（P<0.05）。该处理导致肠道乙酸浓度升高，消化酶和刷状缘酶活性增强（P<0.05）。此外，它降低了肠道通透性（P<0.05），保持了紧密连接（TJ）超微结构的完整性，并在蛋白质和转录水平上增加了TJ和黏附连接（AJ）生物标志物的表达（P<0.05）。从机制上讲，这些影响可能与抗氧化能力增强以及RhoA/ROCK、Sirt1和PI3K/AKT信号通路的协同调节有关。基于体重增加率、饲料转化率、血清二胺氧化酶活性和脂多糖含量，适宜的添加水平分别为1.27×10⁹、1.27×10⁹、1.34×10⁹和1.34×10⁹个细胞/kg。
索氏栖热放线菌改善了草鱼幼鱼的肠道消化吸收能力，维持了肠道结构完整性，从而促进了它们的生长发育。这项工作证明了索氏栖热放线菌作为水产动物益生菌的潜力，并为其在水产养殖中的应用提供了理论依据。
