The composition and function of intracapsular biochemical substances are intrinsically correlated; thus, it is important to quantify intracapsular nutritional composition, including protein, glycogen and lipid content, which are required for embryonic development. To explore the intracapsular fluid nutritional composition of the marine gastropod Hemifusus tuba Gmelin during early developmental stages, the embryonic development was divided into seven stages: fertilized egg, cleavage, morula, blastula, gastrula, veliger and juvenile. Results showed that the amino acids contents ranged from 44.98 to 71.52/100 g. Furthermore, 13 amino acids were identified, including five essential amino acids and eight non-essential amino acids. The contents of aspartic acid, proline, and valine were higher, while the contents of the other ten amino acids were relatively lower. Notably, aspartic acid and proline content varied across embryonic development. In addition, saturated fatty acids (SFAs) were dominant fatty acid components in the intracapsular fluid, in which C18:0 was the main fatty acid. Monounsaturated fatty acids (MUFA) primarily comprised C20:1(n − 9), accounting for 30% of the total fatty acids. At the same time, the content of C18:2(n − 6) decreased significantly from the fertilized egg to the blastula stage (p < 0.05). The content of C20:4(n − 6) from fertilized egg to gastrula stage was significantly reduced (p < 0.05). C22:6(n − 3) was significantly lower in the gastrula than in other stages (p < 0.05). Overall, this study provides new information on the intracapsular fluid nutritional composition of H. tuba, helping enrich the biological knowledge of the early developmental stages of marine gastropods.

中文翻译：

---

海洋腹足动物Hemifusus tuba Gmelin早期发育过程中囊内液营养成分的变化

囊内生化物质的组成和功能具有内在的相关性；因此，重要的是量化囊内营养成分，包括胚胎发育所需的蛋白质、糖原和脂质含量。探讨海洋腹足类半腹鱼的囊内液营养成分Gmelin在早期发育阶段，将胚胎发育分为七个阶段：受精卵、卵裂、桑椹胚、囊胚、原肠胚、软毛胚和幼胚。结果表明，氨基酸含量为44.98～71.52/100 g。此外，鉴定出13个氨基酸，包括5个必需氨基酸和8个非必需氨基酸。天冬氨酸、脯氨酸和缬氨酸的含量较高，而其他十种氨基酸的含量相对较低。值得注意的是，天冬氨酸和脯氨酸含量因胚胎发育而异。此外，饱和脂肪酸（SFA）是囊内液中的主要脂肪酸成分，其中 C18:0 是主要脂肪酸。单不饱和脂肪酸 (MUFA) 主要由 C20:1( n − 9)，占总脂肪酸的 30%。同时，C18:2( n  -6)的含量从受精卵到囊胚期显着降低( p  <0.05)。 受精卵至原肠胚期C20:4( n -6)含量显着降低( p  <0.05)。C22:6( n  - 3) 在原肠胚中显着低于其他阶段 ( p  < 0.05)。总体而言，这项研究提供了有关H的囊内液营养成分的新信息。大号，帮助丰富海洋腹足动物早期发育阶段的生物学知识。