The Effects of Lycopene on the Growth Performance, Antioxidant Capacity, and Liver Health of Hybrid Groupers (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus) Under the Influence of Aflatoxin B1

The continued rise in fishmeal prices and the scarcity of fishery resources have led to an increase in the use of plant-based protein sources in compound feed, making mold contamination in compound feed a frequent occurrence. Aflatoxin B1 (AFB1) contamination in aquaculture feed can seriously harm fish growth and liver health; it is extremely toxic, posing an even greater risk to carnivorous fish such as grouper. Lycopene, a natural carotenoid, has antioxidant and anti-inflammatory physiological functions and may act as a functional feed additive to mitigate damage induced by mycotoxins. This study utilized hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) as the experimental model. An 8-week feeding trial was performed to systematically assess the impact of lycopene supplementation at levels of 0, 200, 400, 600, and 800 mg/kg to a basal diet containing 800 μg/kg AFB1 on the fish’s growth performance, antioxidant capacity, liver health, inflammation-related gene expression, and hepatic transcriptome. The results showed that adding 200 mg/kg lycopene to the feed significantly increased the FWB and SGR (p < 0.05) of hybrid grouper. An appropriate amount of lycopene could enhance the antioxidant capacity of serum and liver, significantly increase the activities of catalase (CAT) and superoxide dismutase (SOD), and significantly decrease serum alanine aminotransferase (ALT) activity while increasing albumin (ALB) levels (p < 0.05). An amount of 200 mg/kg lycopene significantly alleviated AFB1-induced hepatocyte vacuolation, steatosis, and inflammatory cell infiltration, while the protective effect of higher doses was weakened. The gene expression results showed that 200 mg/kg lycopene significantly upregulated the expression of antioxidant-related genes such as cat, sod, and nrf-2, and increased the expression level of the anti-inflammatory factor il10 (p < 0.05). The transcriptome analysis identified a total of 621 differentially expressed genes, which were mainly enriched in metabolic pathways, fatty acid metabolism, PPAR signaling pathway, redox process, ferroptosis, NF-κB signaling pathway, and Toll-like receptor signaling pathway. In summary, the addition of 200 mg/kg lycopene to the feed can effectively alleviate the growth inhibition and liver damage caused by AFB1 in hybrid grouper. Its mechanism of action may be related to enhancing antioxidant defenses, improving liver tissue structure, regulating lipid metabolism, and maintaining immune homeostasis. The research results indicate that lycopene can be used as a natural functional feed additive to alleviate AFB1 toxicity in hybrid grouper aquaculture.