The present study addressed the possible effects of fishwort (Houttuynia cordata) powder (FWP) on Nile tilapia's skin mucus parameter, serum immune response, and growth performance. Three hundred twenty tilapia fingerlings (average weight of 39.06 ± 0.16 g) were divided into four treatments and fed four levels of FWP; 0, 5, 10, and 20 g kg-1 for 72 days. Completed randomised design of the four replications was applied and revealed that fish fed FWP significantly improved skin mucus lysozyme activity (SMLA). The highest value (P < 0.05) was recorded in fish fed 10 g kg-1 FWP. However, no significant difference in SMLA was observed by feeding the fish 5 and 20 g kg-1 FWP. Significant (P < 0.05) enhanced skin mucus peroxidase activity (SMPA) was observed in fish fed 10 g kg-1 FWP, but no significant difference in SMPA was detected between FWP supplemented diets (5 and 20 g kg-1 FWP) and the control group. Regarding serum immunity, dietary administration of FWP showed significantly (P < 0.05) improved serum lysozyme, peroxidase, alternative complement (ACH50), and phagocytosis vs. the control. The highest values of serum immunity (P < 0.05) were recorded in fish fed 10 g kg-1 FWP. However, no significance in respiratory burst activity was observed. Similarly, no significant difference in growth performance, feed conversion ratio, and survival rate was observed in fish fed FWP compared to the control. In summary, diets supplemented with FWP (10 g kg-1) increased the serum and mucosal immunity; however, no FWP supplementations had effects on Nile tilapia growth and survival rate.

中文翻译：

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鱼腥草（鱼腥草）对尼罗罗非鱼皮肤黏膜，血清免疫力和生长性能的影响。

本研究探讨了鱼腥粉（鱼腥草粉）对尼罗罗非鱼皮肤黏液参数，血清免疫反应和生长性能的可能影响。将三百二十条罗非鱼鱼种（平均重量为39.06±0.16克）分为四个处理组，并饲喂四个水平的FWP。0、5、10和20 g kg-1，持续72天。应用了四个重复实验的完全随机设计，结果表明，喂食FWP的鱼可显着改善皮肤粘液溶菌酶活性（SMLA）。饲喂10 g kg-1 FWP的鱼的最高值（P <0.05）。但是，喂鱼5和20 g kg-1 FWP时，未观察到SMLA的显着差异。在饲喂10 g kg-1 FWP的鱼中，观察到显着（P <0.05）增强的皮肤粘液过氧化物酶活性（SMPA），但补充FWP的饮食（5和20 g kg-1 FWP）与对照组之间的SMPA没有显着差异。关于血清免疫性，与对照组相比，饮食中FWP的饮食显着改善（P <0.05）血清溶菌酶，过氧化物酶，替代补体（ACH50）和吞噬作用。饲喂10 g kg-1 FWP的鱼的血清免疫力最高（P <0.05）。但是，没有观察到呼吸爆发活动的意义。同样，与对照组相比，饲喂FWP的鱼在生长性能，饲料转化率和成活率上也没有显着差异。总之，补充FWP（10 g kg-1）的饮食可提高血清和粘膜免疫力。但是，没有添加FWP对尼罗罗非鱼的生长和成活率没有影响。