4-octyl itaconate improves water quality, growth, immunity, blood parameters, and disease resistance of Nile tilapia (Oreochromis niloticus) infected with Aeromonas hydrophila

Abstract

The aquaculture sector has recently shown increasing interest in novel natural molecules as components of eco-friendly, safe, and antibiotic-free diets. The metabolic itaconate molecule, known for its antioxidant, anti-inflammatory, and immunomodulatory properties, has emerged as a promising candidate. However, limited research exists on the specific effects of 4-octyl itaconate on the growth, immunity, inflammation, and disease resistance of Nile tilapia (Oreochromis niloticus). Thereafter, this experiment assessed the impacts of dietary 4-octyl itaconate (DMIC) supplementation on water quality, growth, blood parameters, and inflammation biomarkers of Nile tilapia (Oreochromis niloticus) and resistance to Aeromonas hydrophila infection. The fish (n = 160) were divided equally into four separate groups (each with four replicates). Over a 56-day period, fish (20.97 ± 0.33g) were fed a basal diet mixed with different levels of DMIC: 0 (DMIC0), 50 (DMIC50), 100 (DMIC100), and 200 (DMIC200) mg/kg of diet. All DMIC groups showed improved growth indices and feed intake compared to the control group (P < 0.05). Feed conversion ratio and water temperatures were not affected (P > 0.05). All DMIC-supplemented groups significantly reduced salinity, pH, dissolved oxygen, ammonia, nitrite, and nitrate (P < 0.001). DMIC significantly improved antioxidant levels (superoxide dismutase, glutathione, and catalase enzymes), immunity markers, and blood hematology (P < 0.001). All DMIC-treated groups displayed greater phagocytic activity, while serum levels of MDA, liver, and kidney functions were significantly decreased (P < 0.01). Fish fed with DMIC exhibited a significant reduction in serum levels of the pro-inflammatory cytokines including tumor necrosis factor-α and interferon-γ and interlukin-4 (P < 0.05) compared to the control fish. Fish infected with A. hydrophila and fed DMIC showed higher survival rates. Incorporating 4-octyl itaconate (100 or 200 mg/kg) into the diet of Nile Tilapia has the potential to improve water quality, enhance blood parameters, boost immune function, increase antioxidant capacity, and struggle resistance to A. hydrophila infection for sustainability the productivity and well-being of cultured Tilapia fish.