Chan Ching-Hung, Chen Li-Han, Chen Kuang-Yu, Chen I-Hung, Lee Kung-Ta, Lai Liang-Chuan, Tsai Mong-Hsun, Chuang Eric Y, Lin Ming-Tse, Yan Tsong-Rong
Department of Chemical Engineering and Biotechnology, College of Engineering, Tatung University, Taipei, Taiwan.
Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei, Taiwan.
Anim Microbiome. 2024 Nov 19;6(1):67. doi: 10.1186/s42523-024-00353-0.
Grey mullet (Mugil cephalus) aquaculture is economically vital due to the high value of its roe. However, it faces significant risks from disease outbreaks, particularly from Nocardia seriolae. Current reliance on antibiotics has drawbacks, highlighting the potential of probiotics as a promising alternative. Despite this, no studies have focused on the effects and mechanisms of probiotics in disease prevention and treatment in grey mullet. This study, therefore, investigates the efficacy of probiotics in enhancing disease resistance and promoting growth in grey mullet. Three strains of probiotics, Lacticaseibacillus rhamnosus FS3051, Limosilactobacillus reuteri FS3052, and Bacillus subtilis natto NTU-18, were selected to evaluate their anti-N. seriolae activity and hydrolytic enzyme secretion in vitro. Then, 144 grey mullet were randomly divided into four groups: control, L. rhamnosus FS3051, L. reuteri FS3052, and B. subtilis natto NTU-18. After being fed the corresponding diet for 28 days, fish were measured for immune gene expression and short-term growth followed by challenge of N. seriolae. Survival rates were recorded for 35 days post challenge. Additionally, the gut microbiota of the control and probiotic groups with effects on both growth and protection against N. seriolae were analyzed to investigate the potential role of gut microbiota. Results demonstrated that L. rhamnosus FS3051 and L. reuteri FS3052 inhibited N. seriolae, while B. subtilis natto NTU-18 did not inhibited N. seriolae. Probiotics also had the ability to secrete hydrolytic enzymes. Probiotic-fed grey mullet showed significant improvements in weight gain ratio, feed efficiency, and specific growth rate, particularly in the B. subtilis natto NTU-18 group. Immune gene expression was enhanced by probiotics, especially L. rhamnosus, FS3051, which induced IL-8, IL-1β, TNF-α, IFN-γ, and MHCI. Survival rates post-N. seriolae challenge improved significantly for L. rhamnosus FS3051-fed fish. L. rhamnosus FS3051 also altered the gut microbiota, enriching beneficial genera like Lactobacillus, which correlated positively with immune responses and growth, while reducing Mycoplasma and Rhodobacter, which were negatively correlated with immune responses. This study underscores the potential of probiotics in enhancing disease resistance and growth via regulating gut microbiota in grey mullet.
由于鲻鱼（Mugil cephalus）的鱼籽价值高昂，其水产养殖在经济上至关重要。然而，它面临着疾病爆发带来的重大风险，尤其是由美人鱼诺卡氏菌（Nocardia seriolae）引发的疾病。目前对抗生素的依赖存在弊端，这凸显了益生菌作为一种有前景的替代方案的潜力。尽管如此，尚无研究聚焦于益生菌在鲻鱼疾病预防和治疗中的作用及机制。因此，本研究调查了益生菌在增强鲻鱼抗病能力和促进生长方面的功效。选择了三株益生菌，即鼠李糖乳杆菌（Lacticaseibacillus rhamnosus）FS3051、罗伊氏乳杆菌（Limosilactobacillus reuteri）FS3052和纳豆芽孢杆菌（Bacillus subtilis natto）NTU - 18，以评估它们在体外对美人鱼诺卡氏菌的抗菌活性和水解酶分泌情况。然后，将144条鲻鱼随机分为四组：对照组、鼠李糖乳杆菌FS3051组、罗伊氏乳杆菌FS3052组和纳豆芽孢杆菌NTU - 18组。在投喂相应饲料28天后，测定鱼的免疫基因表达和短期生长情况，随后用美人鱼诺卡氏菌进行攻毒。记录攻毒后35天的存活率。此外，分析了对生长和抵御美人鱼诺卡氏菌均有影响的对照组和益生菌组的肠道微生物群，以研究肠道微生物群的潜在作用。结果表明，鼠李糖乳杆菌FS3051和罗伊氏乳杆菌FS3052能抑制美人鱼诺卡氏菌，而纳豆芽孢杆菌NTU - 18不能抑制。益生菌还具有分泌水解酶的能力。投喂益生菌的鲻鱼在增重率、饲料效率和特定生长率方面有显著改善，尤其是在纳豆芽孢杆菌NTU - 18组。益生菌增强了免疫基因表达，特别是鼠李糖乳杆菌FS3051诱导了IL - 8、IL - 1β、TNF - α、IFN - γ和MHCⅠ的表达。鼠李糖乳杆菌FS3051组的鱼在受到美人鱼诺卡氏菌攻毒后的存活率显著提高。鼠李糖乳杆菌FS3051还改变了肠道微生物群，增加了如乳酸杆菌等有益菌属，这些菌属与免疫反应和生长呈正相关，同时减少了与免疫反应呈负相关的支原体和红杆菌。本研究强调了益生菌通过调节鲻鱼肠道微生物群来增强抗病能力和促进生长的潜力。
