Physiology and comparative transcriptomic analyses reveal the effects of food enrichment on the brain of yellow drum Nibea albiflora (Richardson, 1846).

Food enrichment is a prominent feeding strategy used to enhance the welfare and physiological performance of captive aquatic animals; however, its effects on the brain remain poorly understood. In this study, three feeding regimes with similar nutritional levels-designated as the Control group (commercial diet), Group 1 [90% commercial diet + 10% ice-fresh Palaemon gravieri (Yu, 1930),] and Group 2 [90% commercial diet + 5% ice-fresh P. gravieri + 5% live Perinereis nuntia (Lamarck, 1818)]-were utilized to establish a food enrichment model. Brain tissues were collected after a 60-day feeding trial to investigate the impact of food enrichment on the brain of yellow drum Nibea albiflora (Richardson, 1846). Methods of physiological and comparative transcriptomic analyses were employed to evaluate these effects. The results showed that fish in Group 2 exhibited a markedly enhanced antioxidant capacity and improved neurotransmitter secretion, as evidenced by elevated levels of SOD, T-AOC, AChE, B-CHE, DA, and GABA, along with reduced cortisol levels. Transcriptome analysis revealed that food enrichment significantly influenced genes related to immune response, stress regulation, and visual transduction. The pathways related to hormone synthesis, phototransduction, and synaptic function were significantly enriched. Key genes, including NLRP3, TGFB2, CACNA1E, GNGT1, and PDE6G (upregulated), as well as FOS, GADD45, PRKAB, HSP90A, etc. (downregulated), were found to interact with food enrichment, thereby influencing brain function. The food enrichment feeding strategy for Group 2 fish appears to enhance the brain's capacity for neural excitation transmission and response to stress stimulation, but whether this reflects an overall improved neurophysiological state requires further investigation. In summary, our findings suggested that food enrichment feeding strategy can influence brain function by enhancing antioxidant defense, modulating neurotransmitter levels, and activating vision-related genes.