The aim of this study was to determine the effects of heat-killed Lactobacillus plantarum L-137 (HK L-137) on the growth performances and immune response of juvenile bighead catfish (Clarias macrocephalus). The experiment was conducted with four iso-nitrogenous (44.8 % crude protein) and iso-caloric (20.17 KJ g⁻¹) diets supplemented with different levels (0, 10, 20, and 50 mg kg⁻¹) of HK L-137. The bighead catfish (n = 1800, average body weight: 9.69 ± 0.24 g) were randomly introduced to 200-L composite tanks (filled with 150 L of fresh water) and stocked at 150 fish tank⁻¹ in triplicates per dietary treatment for 60 days. The results showed that the diets supplemented with 10, 20, and 50 mg kg⁻¹ of HK L-137 significantly increased the growth, protein efficiency ratio, feed conversion ratio, survival rate, and lysozyme activity compared to the control. Furthermore, the diets supplemented with 20 and 50 mg kg⁻¹ or 10 and 20 mg kg⁻¹ of HK L-137 significantly enhanced the total white blood cell count or apparent digestibility coefficient of the fish, respectively. The fish fed the HK L-137 diets (at 10, 20, and 50 mg kg⁻¹) revealed lower cumulative mortality than the control after challenge with Aeromonas hydrophila. Our results suggested that dietary supplementation of 10 mg kg⁻¹ HK L-137 is the most efficient in improving the performance and immunity of bighead catfish; however, this should be confirmed in further study under full-scale commercial trials.

本研究的目的是确定热灭活植物乳杆菌L-137 (HK L-137) 对鳙鱼幼鱼 ( Clarias macrocephalus )生长性能和免疫反应的影响。该实验使用四种等氮（44.8 % 粗蛋白）和等热量（20.17 KJ g ^-1）膳食补充不同水平（0、10、20和 50 mg kg ^-1）的 HK L-137 . 将鳙鱼（n = 1800，平均体重：9.69 ± 0.24 g）随机引入 200 L 复合水箱（装满 150 L 淡水）并在 150 个鱼缸^-1中放养，每次饮食处理三次重复 60天。结果表明，日粮中添加了 10、20 和 50 mg kg与对照相比，^-1 HK L-137 显着提高了生长、蛋白质效率比、饲料转化率、成活率和溶菌酶活性。此外，添加20和50 mg kg ^-1或10和20 mg kg ^-1 HK L-137的饮食分别显着提高了鱼的总白细胞计数或表观消化率系数。喂食HK L-137 饮食（10、20 和50 mg kg ^-1）的鱼在用嗜水气单胞菌攻击后显示出比对照更低的累积死亡率。我们的结果表明，膳食补充剂 10 mg kg ^-1HK L-137在提高鳙鱼的性能和免疫力方面最有效；然而，这应该在全面商业试验的进一步研究中得到证实。