The starter diet for Japanese eel (Anguilla japonica) has always been a difficult problem for the realization of total artificial reproduction. Therefore, this research analyzed the nutritional composition of artificially fertilized eggs, and transcriptome of samples from early hatchlings of fry to better understand nutrients requirements. The composition of crude lipid and crude protein in fertilized eggs was 7.24% ± 0.32% and 10.56% ± 0.41%, respectively. Seven kinds of essential amino acids (EAA) were detected but took a comparable lower content (3.19%) than other marine fish eggs. We randomly assembled 265.74 million clean reads and identified 1751 differentially expressed genes (DEGs) (P < 0.01) from pre-leptocephalus larvae. A total of 23 KEGG pathways related to the digestive and metabolic system were detected. Genes related to the secretion pathway of saliva, pancreatic juice and other digestive juices were significantly changed. Transcriptome analysis showed that as larvae aged, glycolytic metabolism and the transcription level of hexokinase (HK) increased significantly (day 0 to 12). This study will facilitate future studies on the nutrition of A. japonica larvae and other biological traits to reproductive research.

中文翻译：

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人工繁殖初孵日本鳗胚胎至头前体的营养成分及转录组分析


日本鳗鱼的入门饮食（日本鳗鲡）一直是实现全人工繁殖的难题。因此，本研究分析了人工受精卵的营养成分以及鱼苗早期孵化样本的转录组，以更好地了解营养需求。受精卵中粗脂质和粗蛋白的组成分别为7.24%±0.32%和10.56%±0.41%。检测到 7 种必需氨基酸 (EAA)，但其含量 (3.19%) 低于其他海水鱼卵。我们随机组装了 26574 万条干净读数，并鉴定了 1751 个差异表达基因（DEG）（磷< 0.01) 来自前头幼虫。共检测到23条与消化和代谢系统相关的KEGG通路。与唾液、胰液和其他消化液分泌途径相关的基因发生显着改变。转录组分析显示，随着幼虫的衰老，糖酵解代谢和己糖激酶 (HK) 的转录水平显着增加（第 0 天至第 12 天）。这项研究将有利于未来的营养研究粳稻幼虫和其他生物学特性以进行生殖研究。