Improving the growth, health status, immune function, and resistance against Aeromonas hydrophila in Nile Tilapia supplemented with dimethyl itaconate.

Background: The aquaculture industry is actively seeking antibiotic-based alternatives to improve fish growth, immunity, and overall health. Natural products contain specific metabolites with immunomodulatory properties. Aim: The main aim of this experiment was to estimate the effects of nutrition dimethyl itaconate (DMIC) on feed utilization, growth traits, blood hematology and metabolites, antioxidant capacity, and inflammation biomarkers of Nile tilapia following an Aeromonas hydrophila infection. Methods: Over 56 days, the fish (weight 20.97 ± 0.33 g, n = 200) were fed a main diet supplemented with different DMIC doses: zero, 50 mg/kg, 100 mg/kg, and 200 mg/kg. Results: All the fish receiving DMIC showed enhanced growth traits (final body weight, Specific growth rate, weight gain) and feed intake compared with the untreated section (p < 0.05), while feed conversion ratio had no significant impact (p > 0.05). In addition, the fish fed with DMIC showed significantly improved levels of glutathione, red blood cells, neutrophils, hemoglobin, and hematocrit in their blood (p < 0.001). Interestingly, the groups fed with DMIC also showed a dose-based increase in serum amounts of IgM (p < 0.05), glucose, total protein, albumin, nitric oxide, and lysosome activity. All the DMIC-intake groups showed greater phagocytic impact, while serum amounts of malondialdehyde, creatinine, alkaline phosphatase, uric acid, aspartate aminotransferase, and alanine aminotransferase were significantly reduced compared to the control treatment (p < 0.01). The fish intake fed with DMIC also appeared to significantly reduce serum amounts of Tumor necrosis factor alpha, interferon-gamma, and interleukin-4 (p < 0.05). Furthermore, fish infected by A. hydrophila and fed with DMIC treatments for 15 days showed a higher survival percentage compared with the untreated groups. Conclusion: Dietary addition with DMIC at doses of 100 or 200 mg/kg may be a novel strategy to enhance the health, immunity, blood profile, antioxidant status, and resistance to A. hydrophila in Nile tilapia fish.