A completely randomized experimental design carried out to investigate the effects of different levels of Pediococcus acidilactici (PA) including 0 (basal diet as a control diet), 1 × 10⁶, 2 × 10⁶, 4 × 10⁶, and 8 × 10⁶ colony-forming unit (CFU) per gram of the diet for 60 days on the mucosal immunity responses, growth, and reproductive performance, in zebrafish, Danio rerio (with mean weigh ± SE: 120 ± 10 mg). The obtained results revealed that the best growth and reproduction indices were related to the concentration of 4 × 10⁶ CFU PA g⁻¹ diet (P < 0.05). The maximum activities of mucosal immune responses including total protein, alternative complement system, IgM, and lysozyme were observed in the fish fed with 4 × 10⁶ CFU PA g⁻¹ diet (P < 0.05). Furthermore, the maximum alkaline phosphatase activity of skin mucus was recorded in the fish fed with 8 × 10⁶ CFU PA g⁻¹ diet (P < 0.05). Fish fed with 4 × 10⁶ CFU PA g⁻¹ diet had the highest villus length and width of the intestine (P < 0.05). Supplementing the diet with 4 × 10⁶ CFU PA g⁻¹ diet more significantly enhanced Cyp19a gene expression in comparison with this in other groups. Hence, PA with a concentration of 4 × 10⁶ CFU g⁻¹ diet can be considered as a proper level of probiotic for improving the health, growth, and reproductive performance of the D. rerio.

进行了完全随机的实验设计，以研究不同水平的乳酸乳酸球菌（PA）的影响，包括0（基础饮食作为对照饮食），1×10 ^6，2 ×10 ^6，4 ×10 ⁶和8×10在斑马鱼Danio rerio中，每克饮食6天每克饮食^6个菌落形成单位（CFU）对粘膜免疫反应，生长和生殖性能的影响（平均体重±SE：120±10 mg）。获得的结果表明，最佳生长和繁殖指数与4×10 ⁶  CFU PA g - ¹日粮的浓度有关（P <0.05）。在饲喂4×10 ⁶  CFU PA g - ¹日粮的鱼中，观察到了粘膜免疫反应的最大活性，包括总蛋白，替代补体系统，IgM和溶菌酶（P  <0.05）。此外，在饲喂8×10 ⁶  CFU PA g - ¹日粮的鱼中，记录了皮肤粘液的最大碱性磷酸酶活性（P  <0.05）。饲喂4×10 ⁶  CFU PA g - ¹日粮的鱼的肠绒毛长度和宽度最高（P  <0.05）。用4×10 ⁶  CFU PA g ^-1饮食补充饮食可显着增强Cyp19a与其他组的基因表达相比。因此，饮食中浓度为4×10 ⁶  CFU g ^-1的PA可被视为适当的益生菌水平，可改善D. rerio的健康，生长和生殖性能。