In the present study, a possible nature immunostimulant and growth promoter—humic substances (HS) originating from Siberian leonardite mineraloid—were tested on juvenile Clarias gariepinus performance. Feed additive was applied onto commercial pelleted feed at four HS levels—0, 1, 3, and 6% w/w (HS0, HS1, HS3, HS6, respectively). Diets were tested in five repetitions (in total, n = 1800 individuals, mean body weight 28.1 ± 6.2 g) for 56 days. Growth and production parameters, fish condition and somatic indices, and overall mortality were evaluated after 14, 28, 42, and 56 days of exposure. Whereas, plasma samples were collected only after 0, 28, and 56 days, when fish health status was assessed with biochemical parameters (total proteins, TP; alanine aminotransferase, ALT; aspartate aminotransferase, AST; lactate dehydrogenase, LDH; cholesterol, CHOL; triglycerides, TAG) and fish antioxidant status with glutathione (reduced glutathione, GSH; oxidized glutathione, GSSG; glutathione ratio GSH/GSSG). Although a significantly positive effect of HS feed additive on growth performance was not found in the present study, moderately positive effects were found regarding biochemical parameters (ALT, AST, LDH, CHOL, and TAG) and antioxidants (GSH/GSSG ratio) that were improved especially in the HS3 group.

中文翻译：

---

腐殖质作为饲料添加剂对非洲鲶鱼生长性能、抗氧化状态和健康状况的影响（Clarias gariepinus, Burchell 1822）

在本研究中，测试了一种可能的天然免疫刺激剂和生长促进剂——源自西伯利亚风化褐煤矿物的腐殖质 (HS)——对Clarias gariepinus幼鱼的表现进行了测试。饲料添加剂以四种 HS 水平——0、1、3 和 6% w/w（分别为 HS0、HS1、HS3、HS6）应用于商业颗粒饲料。饮食以五次重复进行测试（总共n= 1800 个人，平均体重 28.1 ± 6.2 g) 56 天。在暴露 14、28、42 和 56 天后，评估了生长和生产参数、鱼类状况和体细胞指数以及总体死亡率。然而，血浆样本仅在 0、28 和 56 天后收集，此时使用生化参数（总蛋白，TP；丙氨酸转氨酶，ALT；天冬氨酸转氨酶，AST；乳酸脱氢酶，LDH；胆固醇，CHOL；甘油三酯，TAG）和鱼与谷胱甘肽的抗氧化状态（还原型谷胱甘肽，GSH；氧化型谷胱甘肽，GSSG；谷胱甘肽比率 GSH/GSSG）。虽然在本研究中未发现 HS 饲料添加剂对生长性能有显着的积极影响，但在生化参数（ALT、AST、LDH、CHOL、