Black soldier fly (BSF) larvae are potentially an excellent source of calcium for insectivores; however, previous studies have identified that they lack appreciable amounts of fat-soluble vitamins (A, D3 , and E). To make BSF larvae a more complete food item, fat-soluble vitamins should either be provided via gut loading or with a multivitamin dusting supplement. The purpose of this study is to identify factors associated with gut loading vitamin A into BSF larvae and to develop feeding recommendations for a more consistent gut-loading process. Factors that were addressed include the vitamin A concentration added to the diet, length of time given to gut load, moisture content of the diet, and density of larvae during feeding. Diets and larvae were analyzed for vitamin A concentration using high-performance liquid chromatography. Larval vitamin A concentrations increased in a nonlinear fashion with increasing dietary vitamin A. Length of time (F = 150.818, p < .001), moisture content of the diet (F = 41.436, p < .001), and larval density (F = 78.407, p < .001) were all found to be significant factors contributing to the larvae's gut-loading capacity. On the basis of our results and vitamin A recommendations from the National Resource Council for rats and poultry, gut-loading recommendations for BSF larvae when fed to insectivorous reptiles and amphibians are as follows: vitamin A concentration of diet between 16,000 and 20,000 mcg retinol equivalents/kg, gut-loading time period of 24 h, moisture content of the diet approximately 60%, and larval density between 0.1 and 1 larvae per each gram of moist substrate.

中文翻译：

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黑水虻幼虫（Hermetia illucens）维生素A肠道负荷的评价

黑水虻 (BSF) 幼虫可能是食虫动物钙的极好来源；然而，之前的研究表明，它们缺乏可观数量的脂溶性维生素（A、D3 和 E）。为了使 BSF 幼虫成为更完整的食物，脂溶性维生素应该通过肠道负荷或与多种维生素粉补充剂一起提供。本研究的目的是确定与肠道将维生素 A 加载到 BSF 幼虫中的相关因素，并为更一致的肠道加载过程制定喂养建议。解决的因素包括添加到饮食中的维生素 A 浓度、给予肠道负荷的时间长度、饮食的水分含量以及喂养期间幼虫的密度。使用高效液相色谱分析饲料和幼虫的维生素 A 浓度。幼虫维生素 A 浓度随着日粮维生素 A 的增加呈非线性增加。时间长度 (F = 150.818, p < .001)、日粮水分含量 (F = 41.436, p < .001) 和幼虫密度 (F = 78.407, p < .001) 都被发现是影响幼虫肠道负荷能力的重要因素。根据我们的结果和国家资源委员会对大鼠和家禽的维生素 A 建议，BSF 幼虫在喂食食虫爬行动物和两栖动物时的肠道负荷建议如下： 饮食中维生素 A 浓度在 16,000 和 20,000 微克视黄醇等价物之间/kg，肠道负荷时间为 24 小时，饲料的水分含量约为 60%，每克潮湿基质的幼虫密度在 0.1 到 1 只幼虫之间。