Combined effects of vitamin E and temperature on the growth, biochemistry, and natural immune response of juveniles snubnose pompano ( <i>Trachinotus blochii</i> )

This study investigates the combined effects of Vitamin E and temperature on the growth, biochemical composition, and immune responses of juvenile snubnose pompano ( Trachinotus blochii ). A 70-day experiment was conducted with six treatments combining two levels of dietary Vitamin E (0 and 400 mg/kg) and three temperature levels (28°C, 31°C, and 34°C). The results revealed that both temperature and Vitamin E significantly influenced growth performance, feed utilization efficiency, protein and lipid content, and certain immune parameters (P &lt; 0.05). Fish reared at 34°C with 400 mg/kg vitamin E demonstrated the highest growth indicators (SGR L , SGR W ), protein efficiency, hepatosomatic index (HSI), and immune response, as indicated by elevated serum lysozyme levels, phagocytic activity, and white blood cells. Temperature notably affected lysozyme and respiratory burst activity, with values increasing at higher temperatures. Vitamin E supplementation improved these metrics regardless of temperature, increasing protein efficiency and reducing feed intake and feed conversion ratio (FCR). Moreover, Vitamin E enhanced immune responses, including increased white blood cell (WBC) counts and phagocytic activity. No interactive effects between Vitamin E and temperature were observed (P &gt; 0.05). Overall, Vitamin E (400 mg/kg) positively influenced growth, biochemical composition, and immunity in snubnose pompano, particularly at elevated temperatures. The findings demonstrate that dietary vitamin E can enhance growth and immune performance, particularly under elevated temperatures, providing a basis for optimizing vitamin E use in snubnose pompano aquaculture.