Nutritional Immunomodulation in Aquatic Species

Aquatic animals rely primarily on innate defences supplemented by adaptable immune mechanisms, both of which can be shaped by diet. Nutritional immunomodulation harnesses functional ingredients—such as specific amino acids, vitamins, fatty acids, minerals, prebiotics and probiotics—to enhance resistance to pathogens, reduce inflammatory damage and improve overall health. Key mechanisms include modulation of oxidant–antioxidant balance, support of mucosal barrier integrity, regulation of cytokine networks and interplay with neuroendocrine stress pathways. Optimising feed formulations with targeted nutrients offers a sustainable alternative to prophylactic antibiotics or vaccines, fostering welfare and productivity across diverse aquaculture systems worldwide.

Research from Nature Portfolio

Recent studies have explored tryptophan’s dual role in neuroendocrine and immune communication. In one investigation, dietary tryptophan supplementation altered activity in the hypothalamic–pituitary–interrenal axis, leading to reduced cortisol output and a shift towards anti-inflammatory cytokine profiles under stress, effects that appeared to be mediated through enhanced serotonergic signalling. An earlier foundational work demonstrated that both deficiency and excess of dietary tryptophan compromise inflammatory defences: insufficient tryptophan weakened macrophage and lymphocyte functions during infection, whereas supraphysiological levels elevated cortisol and disrupted immune gene expression, ultimately affecting disease resistance. Together, these reports underscore the importance of precise amino acid dosing to fine-tune host resilience and stress tolerance.

Nutritional Immunomodulation in Aquatic Species publication trend

The graph below shows the total number of articles in nutritional immunomodulation in aquatic species across all publications each year (not limited to Nature Index journals).

Technical terms

Immunomodulation: Adjustment of immune responses through external factors such as diet, stressors or pharmacological agents to achieve a desired outcome.

Cytokines: Small signalling proteins released by immune cells that regulate inflammation, cell recruitment and communication between innate and adaptive systems.

Hypothalamic–Pituitary–Interrenal (HPI) axis: The neuroendocrine pathway in fish analogous to the mammalian stress axis, coordinating hormonal responses to stress and influencing immune function.

Oxidative burst: Rapid production of reactive oxygen species by immune cells to neutralise pathogens, balanced by antioxidants to prevent tissue damage.

Mucosal immunity: Immune protection at epithelial surfaces such as the gut lining, involving secreted antibodies, antimicrobial peptides and barrier-supporting cells.

References

1. Immunonutrition: facilitating mucosal immune response in teleost intestine with amino acids through oxidant-antioxidant balance. Frontiers in Immunology (2023).
2. Synergistic Effects of Dietary Tryptophan and Dip Vaccination in the Immune Response of European Seabass Juveniles. International Journal of Molecular Sciences (2024).
3. Dietary tryptophan intervention counteracts stress-induced transcriptional changes in a teleost fish HPI axis during inflammation. Scientific Reports (2024).
4. Dietary Tryptophan Plays a Role as an Anti-Inflammatory Agent in European Seabass (Dicentrarchus labrax) Juveniles during Chronic Inflammation. Biology (2024).
5. Dietary tryptophan deficiency and its supplementation compromises inflammatory mechanisms and disease resistance in a teleost fish. Scientific Reports (2019).