The synergistic effect of phytochemical compounds in extract on growth, antibacterial activity, and resistance to vibriosis in Penaeus monodon

This study explored whether there is a synergistic effect of Ocimum basilicum extract (OBE), Zingiber zerumbet extract (ZZE), and Boesenbergia pandurata extract (BPE) on the ability to suppress Vibrio harveyi and V. parahaemolyticus bacteria, provide pathogen protection, and influence growth in tiger shrimp ( Penaeus monodon ). Overall, these extracts exhibited strong antibacterial activity, with OBE exhibiting the largest clear zone and highest level of antibacterial activity against both bacteria, followed by ZZE and BPE. This is in line with a decrease in bacteria (total Vibrio count, TVC) in the shrimp body and an increase in non-specific shrimp immunity in the form of total hemocyte count (THC), phenoloxidase activity (PO), phagocytic activity (PA), and survival rate (SR). All extracts increased the average daily growth (ADG) and reduced the feed conversion ratio (FCR) over 8 weeks. Moreover, BPE administration resulted in the highest growth when compared to ZZE and OBE extracts. Notably, shrimp feed supplementation with OBE, ZZE, and BPE provided substantial prophylactic benefits, resulting in survival rates exceeding 70% against V. harveyi infection and 60% against V. parahaemolyticus infection, demonstrating significant improvements when compared to the saline control group. This study demonstrates that the administration of OBE, ZZE, and BPE can synergistically improve the non-specific immune system, resistance to pathogen activity, and the growth of P. monodon shrimp.