Rattanawongwiboon Thitirat, Paankhao Natthapong, Buncharoen Wararut, Pansawat Nantipa, Kumwan Benchawan, Meachasompop Pakapon, Kantha Phunsin, Pansiri Tanavan, Tangthong Theeranan, Laksee Sakchai, Paankhao Suwinai, Promsee Kittipong, Jaroenkittaweewong Mongkhon, Lertsarawut Pattra, Srisapoome Prapansak, Hemvichian Kasinee, Uchuwittayakul Anurak
Thailand Institute of Nuclear Technology (Public Organization), Nakorn Nayok 26120, Thailand.
Kamphaeng Saen Fisheries Research Station, Faculty of Fisheries, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom 73140, Thailand.
Polymers (Basel). 2025 Jul 31;17(15):2101. doi: 10.3390/polym17152101.
This study investigated the immunonutritional potential of high-molecular-weight (Mw~85 kDa), non-degraded chitosan (NCS) and gamma-radiation-degraded, low-molecular-weight chitosan (RCS) incorporated into aquafeeds for Nile tilapia (). RCS was produced by γ-irradiation (10 kGy) in the presence of 0.25% (/) HO, yielding low-viscosity, colloidally stable nanoparticles with Mw ranging from 10 to 13 kDa. Five diets were formulated: a control, NCS at 0.50%, and RCS at 0.025%, 0.050%, and 0.075%. No adverse effects on growth were observed, confirming safety. Immune gene expression (e.g., , , ), antioxidant markers (e.g., reduced MDA, increased GSH and GR), and nonspecific humoral responses (lysozyme, IgM, and bactericidal activity) were significantly enhanced in the NCS-0.50, RCS-0.050, and RCS-0.075 groups. Notably, these benefits were achieved with RCS at 10-fold lower concentrations than NCS. Following challenge with , fish fed RCS-0.050 and RCS-0.075 diets exhibited the highest survival rates and relative percent survival, highlighting robust activation of innate and adaptive immunity alongside redox defense. These results support the use of low-Mw RCS as a biologically potent, cost-effective alternative to traditional high-Mw chitosan in functional aquafeeds. RCS-0.050 and RCS-0.075 show strong potential as immunonutritional agents to enhance fish health and disease resistance in aquaculture.
本研究调查了添加到尼罗罗非鱼水产饲料中的高分子量（Mw~85 kDa）、未降解的壳聚糖（NCS）和经γ射线辐射降解的低分子量壳聚糖（RCS）的免疫营养潜力。RCS是在0.25%（/）H₂O₂存在下通过γ射线辐射（10 kGy）产生的，产生了低粘度、胶体稳定的纳米颗粒，Mw范围为10至13 kDa。配制了五种饲料：一种对照饲料、0.50%的NCS饲料，以及0.025%、0.050%和0.075%的RCS饲料。未观察到对生长的不利影响，证实了其安全性。在NCS-0.50、RCS-0.050和RCS-0.075组中，免疫基因表达（如 、 、 ）、抗氧化标志物（如MDA降低、GSH和GR增加）以及非特异性体液反应（溶菌酶、IgM和杀菌活性）均显著增强。值得注意的是，RCS达到这些益处的浓度比NCS低10倍。在用 攻击后，喂食RCS-0.050和RCS-0.075饲料的鱼表现出最高的存活率和相对存活率百分比，突出了先天免疫和适应性免疫以及氧化还原防御的强大激活。这些结果支持在功能性水产饲料中使用低分子量的RCS作为传统高分子量壳聚糖的一种具有生物活性、成本效益高的替代品。RCS-0.050和RCS-0.075作为免疫营养剂在增强水产养殖中鱼类健康和抗病能力方面具有强大潜力。
