The current work was planned to assess the effects of dietary microalga, Nannochloropsis oculata (NP) on the growth indices, serum biochemistry, non-specific immunity, and resistance of Nile tilapia (Oreochromis niloticus) juveniles against challenge with pathogenic Aeromonas veronii. Fish (10.21 ± 0.28 g) were randomly divided into four treatments in triplicates and were fed on diets supplemented with different levels of NP (0, 5, 10, and 15%) for eight weeks. The results showed that the dietary 5% NP significantly improved the growth parameters (final body weight, weight gain, specific growth rate, and total feed intake) (P < 0.05). Meanwhile, the feed conversion ratio was significantly decreased in NP-supplemented groups with respect to the control group. The serum protein profile (total protein, albumin, globulin, and albumin/globulin ratio) was significantly decreased by 15% NP supplemented group. Meanwhile, liver enzymes (alanine transaminase, and aspartate transaminase) activities were not significantly affected by NP dietary supplementation (P < 0.05). Serum lysozyme activity, nitric oxide (NO), and nitroblue tetrazolium (NBT) levels were significantly enhanced only in 5% NP supplemented group (P < 0.05). Interestingly, the hepatopancreatic and intestinal tissues had apparently normal histomorphology of Nile tilapia fed at 5% NP-supplemented diets. Significant upregulation of cytokines [interleukin 1beta (IL-1β), interleukin 8 (IL-8), interferon-gamma (IFN-γ), transforming growth factor-beta (TGF- β), and tumor necrosis factor-alpha (TNF-α)], with significant downregulation of the antioxidant gene [superoxide dismutase (SOD)] in 10% and 15% NP supplemented groups. Attractively, the relative level of protection (RLP) against challenge with pathogenic A. veronii was significantly elevated in 10% and 15% NP supplemented groups. Conclusively, the obtained results reflect the beneficial roles of dietary NP to improve growth and boost the immune responses of Nile tilapia.

目前的工作计划是评估膳食微藻，拟南芥（NP）对生长指数，血清生化，非特异性免疫以及尼罗罗非鱼（Oreochromis niloticus）少年抵抗病原性气单胞菌攻击的影响。将鱼（10.21±0.28 g）随机分成四份，一式三份，并在补充了不同水平NP（0％，5％，10％和15％）的饮食下喂养八周。结果表明，饮食中5％NP显着改善了生长参数（最终体重，体重增加，比生长率和总饲料摄入量）（P <0.05）。同时，相对于对照组，NP补充组的饲料转化率显着降低。15％NP补充组的血清蛋白谱（总蛋白，白蛋白，球蛋白和白蛋白/球蛋白比）显着降低。同时，NP饮食补充对肝酶（丙氨酸转氨酶和天冬氨酸转氨酶）的活性没有显着影响（P  <  0.05）。补充5％NP的人群血清溶菌酶活性，一氧化氮（NO）和硝基蓝四氮唑（NBT）水平显着提高（P  <  0.05）。有趣的是，肝胰脏和肠道组织的尼罗罗非鱼组织形态学正常，饲喂5％NP的日粮。细胞因子[白介素1β（IL-1β），白介素8（IL-8），干扰素-γ（IFN-γ），转化生长因子-β（TGF-β）和肿瘤坏死因子-α（TNF -α）明显上调α）]，并在10％和15％的NP补充组中显着下调了抗氧化剂基因[超氧化物歧化酶（SOD）]。有吸引力的是，相对水平的保护（RLP）抵抗致病性拟南芥攻击在10％和15％的NP补充组中，其显着升高。结论是，所获得的结果反映了日粮NP改善尼罗罗非鱼生长和增强其免疫反应的有益作用。