Housefly larvae are widely used in livestock breeding industry as a functional feed additive with immunostimulant properties, but their effects as dietary additive are poorly understood in aquatic animals. We conducted an eight‐week rearing experiment to determine the effects of housefly larvae (complete) on growth performance, immunity and intestinal microbiota in swamp eel (Monopterus albus). Dietary treatments were as follows: BD (control group, fed a basal diet), FL7 (fly larvae supplemented once weekly, i.e., 6‐day basal diet, 1‐day larvae) and FL3 (larvae supplemented every third day, i.e., 2‐day basal diet, 1‐day larvae). The final body weight (FBW) and weight gain (WG) of the FL3 group significantly (p < .05) increased. Hepatosomatic index (HSI) and malondialdehyde (MDA) concentration significantly decreased in FL3 and FL7 groups. The expression of immune‐related genes was also influenced by the fly larvae. Aeromonas hydrophila challenge experiment produced higher survival rates in the FL3 (75%) and FL7 (37.5%) groups. Fly larvae also affected the composition of gut microbiota: the abundance of Bacteroides increased, and Pseudomonas decreased, in the treatment groups. Dietary supplementation of housefly larvae has positive effects on the growth and immunity of swamp eel, and we suggest supplementing housefly larvae every third day.

中文翻译：

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饲喂补充家蝇幼虫（家蝇）的饲料的沼泽鳗鱼（Monopterus albus）的生长性能，免疫力和肠道菌群

家蝇幼虫作为具有免疫刺激特性的功能性饲料添加剂被广泛用于畜牧业，但是在水生动物中人们对它们作为膳食添加剂的作用了解甚少。我们进行了为期八周的饲养实验，以确定家蝇幼虫（完整）对沼泽鳗（Monopterus albus）的生长性能，免疫力和肠道菌群的影响。饮食治疗方法如下：BD（对照组，以基础饮食喂养），FL7（蝇幼虫，每周补充一次，即6天基础饮食，1天幼虫）和FL3（幼虫，每三天补充一次，即2天）一日基本饮食，一日幼虫）。FL3组的最终体重（FBW）和体重增加（WG）显着（p <.05）增加。FL3和FL7组的肝体指数（HSI）和丙二醛（MDA）浓度显着降低。免疫相关基因的表达也受到蝇幼虫的影响。嗜水气单胞菌攻击实验在FL3（75％）和FL7（37.5％）组中具有较高的存活率。蝇幼虫也影响肠道菌群的组成：在治疗组中，拟杆菌的数量增加，假单胞菌数量减少。膳食补充家蝇幼虫对沼泽鳗鱼的生长和免疫具有积极作用，我们建议每三天补充一次家蝇幼虫。