The study analysed the effects of dietary resveratrol supplementation, either alone or in combination, with fumaric acid on the zootechnical performance and bioenergetics parameters of juvenile Litopenaeus vannamei. A dose–response trial was conducted with 0, 10, 60, 110, and 160 mg·kg⁻¹ of resveratrol. Subsequently, a second experiment was performed with shrimp from the control group and the best-performing resveratrol group. The treatments were control (C), fumaric acid 8.47 g·kg⁻¹ (F), resveratrol (R) and R + F (RF). Growth performance (final weight gain (g), specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER)) and the concentration of energy-yielding molecules evaluated. Shrimp fed with 60 mg·kg⁻¹ of resveratrol showed higher weight gain, SGR, protein and glucose concentrations in the muscle, increased PER, and lower FCR (ANOVA and Tukey HSD post hoc test (p < 0.05). Combined supplementation (RF) further enhanced growth performance and protein, glucose, and glycogen concentrations (p < 0.05) (ANCOVA test; p < 0.05). The zootechnical responses were also improved, where in 14 days the animals gained almost three grams of weight, with an FCR of 1.14 ± 0.03 and SGR of 6.99 ± 0.17% per day (p < 0.05). Overall, the combined supplementation of resveratrol and fumaric acid acted as an effective metabolic modulator, improving metabolic status of L. vannamei.