Dietary essential oils of Thymus vulgaris and Artemisia annua in sea bream infected with Tenacibaculum maritimum

Tenacibaculosis, caused by Tenacibaculum maritimum, poses a significant threat to Mediterranean aquaculture, notably impacting the gilthead seabream (Sparus aurata; Linnaeus, 1758). This study aimed to assess the efficacy of dietary supplementation with essential oils of Thymus vulgaris (0.25%, 0.5%) and Artemisia annua (0.25%, 0.5%) in mitigating the effects of experimental T. maritimum infection. Fish were fed supplemented diets for 15 days pre-infection and monitored for 20 days post-infection. Results showed T. vulgaris at 0.5% significantly reduced mortality to 2.2% compared to controls (18.9%), while A. annua at 0.5% yielded intermediate mortality (4.4%). Both oils reduced infection prevalence (T. vulgaris 0.5%: 2.2% vs. control: 16.7%), with T. vulgaris groups exhibiting milder histopathological lesions. Notably, A. annua at 0.5% induced focal renal hemorrhages, suggesting dose-dependent toxicity. Thyme essential oil demonstrates promise as a functional feed additive, whereas A. annua warrants further safety evaluation.