Fosse Malene Malchus, Méndez Laura Rivera, Rodríguez-Ramos Tania, Dixon Brian, Sundh Henrik, Olsen Rolf Erik
Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
Department of Biology, University of Waterloo, Waterloo, ON, Canada.
Front Immunol. 2025 Jun 18;16:1616076. doi: 10.3389/fimmu.2025.1616076. eCollection 2025.
Functional feed ingredients can enhance the fish gut integrity and immune resilience during challenging situations in the aquaculture industry. This study used the RTgutGC cell line - derived from rainbow trout intestinal epithelium, to evaluate the immunomodulatory and barrier effects of selected ingredients. These included β-glucan from (BG40 and BG60), laminarin extracted from (Lam60 and Lam90), and bioactive peptides with antioxidative and immunomodulatory potential; carnosine (Carn100 and Carn120) and salmon hydrolysate (FPH300 and FPH600). Cells were exposed for 24 hours at two concentrations (maintaining 100 % and 80 % viability), and effects on transepithelial resistance (TEER), permeability (P) and gene expression (qPCR) were assessed before and after a 6-hour lipopolysaccharide (LPS) challenge. High-dose laminarin and both salmon hydrolysate concentrations elevated mRNA encoding for pro-inflammatory cytokines (, , and ; < 0.05). All ingredients except carnosine significantly reduced TEER ( < 0.05) often with downregulation of barrier genes. Low-dose carnosine and laminarin reduced P of Lucifer yellow, indicating less barrier disruption. LPS induced inflammation, barrier dysfunction and reduced proliferation. These effects were modulated by high-dose β-glucan and both laminarin concentrations, which significantly reduced expression ( < 0.05). High-dose salmon hydrolysate also tended to reduce ( = 0.05) and increased expression ( < 0.001), suggesting tissue recovery. Low-dose laminarin and both carnosine concentrations upregulated post-challenge ( < 0.05). These findings support the RTgutGC model as a valuable screening tool and provides new insights into the biological activity and immunomodulatory effects of various functional feed ingredients.
功能性饲料成分可在水产养殖业面临挑战的情况下增强鱼类肠道完整性和免疫恢复力。本研究使用源自虹鳟鱼肠上皮的RTgutGC细胞系，评估所选成分的免疫调节和屏障作用。这些成分包括来自[具体来源]的β-葡聚糖（BG40和BG60）、从[具体来源]提取的海带多糖（Lam60和Lam90）以及具有抗氧化和免疫调节潜力的生物活性肽；肌肽（Carn100和Carn120）和鲑鱼水解物（FPH300和FPH600）。细胞在两种浓度下暴露24小时（保持100%和80%的活力），并在6小时脂多糖（LPS）刺激前后评估对跨上皮电阻（TEER）、通透性（P）和基因表达（qPCR）的影响。高剂量海带多糖以及两种鲑鱼水解物浓度均提高了促炎细胞因子编码的mRNA（[具体细胞因子]；P<0.05）。除肌肽外的所有成分均显著降低了TEER（P<0.05），且通常伴随着屏障基因的下调。低剂量肌肽和海带多糖降低了荧光素黄的P值，表明屏障破坏减少。LPS诱导炎症、屏障功能障碍并降低增殖。这些作用受到高剂量β-葡聚糖和两种海带多糖浓度的调节，它们显著降低了[具体基因]表达（P<0.05）。高剂量鲑鱼水解物也倾向于降低[具体指标]（P = 0.05）并增加[具体基因]表达（P<0.001），表明组织恢复。低剂量海带多糖和两种肌肽浓度在刺激后上调了[具体基因]（P<0.05）。这些发现支持RTgutGC模型作为一种有价值的筛选工具，并为各种功能性饲料成分的生物活性和免疫调节作用提供了新的见解。
