Zebrafish (Danio rerio) embryo extracts improve immune response, antioxidant capacity, and stress tolerance of ship sturgeon (Acipenser nudiventris)

• Hematology and immune response improved in ship sturgeon with Zebrafish embryo extract (ZE). • Antioxidant enzyme activity in serum and mucus increased with ZE injection. • After salt stress, fish injected with ZE from the gastrula had a higher survival rate. • Reduced of stress parameters in fish by injection of ZE from the gastrula occurred. Stem cell research has emerged as a prominent area in biomedical sciences; however, its potential application as an immunostimulant in farmed animals has not yet been investigated. The present study evaluated the effects of zebrafish ( Danio rerio ) embryo extract (ZE), derived from different developmental stages (morula, blastula, and gastrula) and administered at graded doses (0, 10, 25, and 50 mg/kg body weight), on hematological parameters, immune responses, antioxidant status, serum biochemical enzyme activity, and stress tolerance following salinity challenge in ship sturgeon ( Acipenser nudiventris ). Fish with an initial weight of 20.11 ± 0.78 g were injected and reared for two weeks in triplicate groups. ZE administration significantly enhanced hematological indices, including hemoglobin concentration, hematocrit value, and red blood cell count. Immune parameters, such as serum total protein, lysozyme activity, alternative complement pathway activity, and immunoglobulin levels in serum and mucus, were also significantly increased compared with the control group. In addition, antioxidant enzyme activities, including superoxide dismutase, catalase, glutathione, and glutathione peroxidase, were significantly elevated, whereas alanine aminotransferase activity was significantly reduced in ZE-treated fish. Following salinity stress, fish injected with gastrula-stage ZE at 50 mg/kg body weight exhibited significantly higher survival rates and significantly lower plasma glucose and cortisol levels than the control group. In conclusion, ZE, particularly the gastrula-stage extract administered at 50 mg/kg body weight, demonstrated potent immunostimulatory and antioxidative properties and enhanced stress resilience in ship sturgeon.