The current study evaluated the effects of nano delivery of Spirulina platensis on growth performance, digestive enzymes, and biochemical, immunological, and antioxidative status, as well as resistance to Aeromonas veronii and some physical stressor challenges in Nile tilapia, Oreochromis niloticus. Three experimental fish groups (n = 270) with mean weights of 26 ± 0.30 g and mean lengths of 10 ± 0.5 cm were used; the first additive-free basal diet served as the control group, whereas the following two groups were supplemented with spirulina nanoparticles (SPNP) at 0 (control), 0.25, and 0.5%/kg diet for 4 weeks. Following the feeding trial, fish were challenged with hypoxia, cold stresses, and pathogenic bacteria (A. veronii) infection (9 × 108 CFU/ml). SPNP supplementation, especially 0.5%, (p < 0.05) significantly increased growth performance (specific growth rate % day-1, feed conversion ratio, and length gain rate %), immunological (plasma lysozyme and liver nitrous oxide) antioxidants (superoxide dismutase, catalase, and glutathione peroxidase in liver), biochemical (aspartate aminotransferase, alanine transaminase, glucose, and cortisol concentrations in plasma) assays, and digestive enzymes (lipase and amylase in plasma). The expression of liver's heat shock protein 70 (HSP70) and interleukin 1, beta (IL-1β) genes showed a significant upregulation outline of 0.5% SPNP > 0.25% SPNP > 0% SPNP compared with the control. Protection in the incorporated fish groups exposed to A. veronii was 100% compared with the control group, which showed 50% cumulative mortalities. In conclusion, dietary SPNP supplementation improved growth performance, antioxidant activity, immune response, digestive enzymes, related gene expression, and resistance of Nile Tilapia to hypoxia, cold, and A. veronii infection. Thus, SPNP could be used as a natural therapy for controlling those stressors.

中文翻译：

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纳米螺旋藻膳食补充剂可增强尼罗罗非鱼，尼罗罗非鱼（Oreochromis niloticus）的生长，抗氧化和免疫反应，消化和保护，使其免受Veronii气单胞菌和某些身体应激源的侵害。

目前的研究评估了螺旋藻纳米递送对生长性能，消化酶，生化，免疫和抗氧化状态的影响，以及对尼罗罗非鱼，尼罗罗非鱼的耐维罗纳气单胞菌和一些物理应激挑战的影响。使用了三个实验鱼群（n = 270），平均体重为26±0.30 g，平均长度为10±0.5 cm。第一个无添加剂基础饮食作为对照组，而随后的两组在4周时分别以0（对照组），0.25和0.5％/ kg的饮食补充螺旋藻纳米颗粒（SPNP）。饲喂试验后，鱼面临缺氧，寒冷压力和病原菌（A. veronii）感染（9×108 CFU / ml）的攻击。补充SPNP，尤其是0.5％（p <0。05）显着提高了生长性能（第1天的特定生长率％，饲料转化率和长度增加率％），免疫性（血浆溶菌酶和肝脏一氧化二氮）抗氧化剂（肝脏中的超氧化物歧化酶，过氧化氢酶和谷胱甘肽过氧化物酶），生化（血浆中的天冬氨酸氨基转移酶，丙氨酸转氨酶，葡萄糖和皮质醇浓度）测定法和消化酶（血浆中的脂肪酶和淀粉酶）。与对照组相比，肝脏的热休克蛋白70（HSP70）和白介素1（β-1（IL-1β））基因的表达显示出明显的上调轮廓，即0.5％SPNP> 0.25％SPNP> 0％SPNP。暴露于ver.ii的掺入鱼群中的保护与对照组相比为100％，后者显示出50％的累积死亡率。结论，饮食中SPNP的添加改善了生长性能，抗氧化活性，免疫反应，消化酶，相关基因表达以及尼罗罗非鱼对缺氧，感冒和ver.ii感染的抵抗力。因此，SPNP可用作控制那些应激源的自然疗法。