Characterization and Analysis of the Functional Differences of the Two Eclosion Hormones in Regulating Molting in the White Shrimp Litopenaeus vannamei

<i>Litopenaeus vannamei</i>, with an annual production of 5-6 million tons and a value of USD 50-60 billion, is a cornerstone of global aquaculture. However, molting-related losses of 5-20% significantly impact this industry, and the physiological mechanisms of molting remain unclear. This study aims to elucidate the role of eclosion hormone (EH) in molting regulation and enhances the understanding of molting physiology in <i>L. vannamei</i>. This study investigated the role of (EH) in <i>L. vannamei</i> molting regulation. Two <i>EH</i> cDNAs, <i>LvEH I</i> and <i>LvEH II</i>, were identified, and their expression patterns across tissues and seven molting stages (A, B, C, D0, D1, D2, and D3) were analyzed. <i>LvEH I</i> was predominantly expressed in the gill, epidermis, and eyestalk, while <i>LvEH II</i> was mainly expressed in the eyestalk and brain. <i>LvEH I</i> was highly expressed in the eyestalk, epidermis, and gills at the D2 and D3 stages of molting, whereas <i>LvEH II</i> was highly expressed in both the D2 (brain) and D3 (eyestalk) stages. RNA interference (RNAi) targeting <i>LvEH I</i> revealed its critical role in molting, as silencing <i>LvEH I</i> disrupted the expression of molting-regulation genes, <i>ETH</i>, <i>CCAP</i>, <i>CHH</i>, <i>EH II</i>, <i>CDA</i>, and bursicon (<i>Burs</i>), significantly delaying the molting process. These findings highlight both <i>LvEH I</i> and <i>LvEH II</i> as indispensable for normal molting in <i>L. vannamei</i> and provide a foundation for developing effective molting management strategies to reduce industry losses.