Two prominent feed additives, organic acids (OA) and phytogenic compounds (essential oils or EO), are emerging as potential antimicrobial agents, although their modes of action vary based on bacterial type. While organic acids are recognized for their potential in enhancing nutrient utilization and antimicrobial properties across several animal industries, including aquaculture, essential oils are complex mixtures of volatile compounds known for their antioxidant, anti-inflammatory, and antimicrobial activitie s. A 12-week study, 15 g hybrid striped bass (HSB) were fed to apparent satiation with diets incorporating organic acids (sodium butyrate and sodium diformate ), essential oils (carvacrol, thymol, allicin, and cinnamaldehyde), or a combined OA and EO formulation. The study aimed to assess the effects of these additives on HSB growth performance and health indices. Essential oil supplementation led to greater weight gains in fish compared to organic acid supplementation. However, health parameters, including hepatosomatic index (HSI) and intraperitoneal fat (IPF), showed variable outcomes. Analyses on SOD activity, glucose, lactate, and TBARS revealed no significant variations in glucose, lactate, and SOD activity across treatments. However, significant differences in TBARS were observed in the essential oil blend and the organic acid blend. For the gene expression. Intestinal HSP70 was upregulated for allicin but downregulated in all treatments in the liver. MetA was upregulated in all intestinal treatments and specifically by cinnamaldehyde in the liver; all other treatments were downregulated. TGFβ was downregulated in all treatments except for cinnamaldehyde in the intestine. CYP1A1 was upregulated by cinnamaldehyde in the intestine and upregulated in the liver across treatments.