Immunoprotective effects of Taiwanese indigenous cinnamon (Cinnamomum osmophloeum) leaf hot-water extract on white shrimp (Penaeus vannamei) challenged with Vibrio parahaemolyticus: Regulati

Abstract

This study investigated the immunoprotective effects of dietary Cinnamomum osmophloeum leaf hot-water extract (CLWE) on autophagy, apoptosis, and histological assessment in white shrimp after exposure to Vibrio parahaemolyticus. Firstly, autophagy- and apoptosis-related genes are widely expressed across white shrimp, with hemocyte and the hepatopancreas exhibiting the highest baseline activity. In vitro analyses demonstrate that CLWE treatment significantly upregulates autophagy and apoptosis, thereby enhancing cellular homeostasis. The challenge test involved feeding white shrimp diets containing CLWE 0, 0.5, and 5 g kg(-1) (identified as CLWE 0, 0.5, and 5) for 14 days and subsequently injected with V. parahaemolyticus. Analyses were performed at 0, 24, 48, 96, and 168 h post-injection. After bacterial challenge, autophagy- and apoptosis-related genes were highly increased in hemocytes and hepatopancreas at 24-48 h, indicating early activation of cellular defense mechanisms. This response was followed by a significant decline from 96 to 168 h, demonstrating immunological resolution and recovery. Histological analysis revealed that CLWE-fed shrimp preserved intestinal and hepatopancreatic structural integrity, with less epithelial disruption and accelerated tissue restoration compared to non-supplemented controls. Overall, these findings show that CLWE improves immune resilience to V. parahaemolyticus by promoting a balanced, time-dependent regulation of autophagy and apoptosis, cellular immunity, and tissue homeostasis, highlighting its potential as a functional dietary immunomodulator in sustainable white shrimp aquaculture.