Dietary Chamomile Nanoparticles Enhance Growth, immunity and Disease Resistance in the Nile Tilapia (Oreochromis niloticus) challenged with Aeromonas hydrophila

Aeromonas hydrophila is a significant foodborne pathogen with economic consequences in aquaculture. This study investigated its prevalence in the Nile tilapia from fish farms in Kafr El-Shaikh Governorate, revealing a 39% infection rate. All isolates carried the aerA gene, and 50% had the hlyA gene. An in vivo trial was conducted to assess the effects of dietary Nano Chamomile on the Nile tilapia over 60 days. Fish were divided into five groups receiving diets with 0.0% (control), 0.5%, 1.0%, 1.5%, and 2.0% Nano Chamomile. Results showed significant improvements in growth performance, feed utilization, immune responses (white blood cell and lymphocyte counts, lysozyme activity, phagocytic activity), and antioxidant enzymes (catalase, superoxide dismutase). Proinflammatory gene expression (IL6, IL-1β, TNF) was significantly downregulated in the 1.0 and 1.5% groups. These groups also exhibited reduced clinical symptoms associated with infection. The optimal effects were observed at 1.5% (15 g/kg) Nano Chamomile supplementation.