When a fish encounter invading pathogen, both the innate and adaptive immune systems will be actively triggered. If the pathogen overwhelms the innate immune response and persists, the adaptive immune responses is then initiated. Increasing evidence shows that production conditions such as densities, thermal fluctuations or current aquafeed formulations, negatively impact fish immunocompetence. Health promoting additives can be used as a preventive strategy to restore immunocompetence and reduce the severity of infections during production. SANACORE®GM (SNGM) is a health promoting additive widely used in marine fish feed for the prevention of bacterial and parasite infections.
This study aimed to elucidate the immunoregulatory mechanisms of SNGM to restore immunocompetence in gilthead sea bream (Sparus aurata). We used multi-tissue proteomics approach to differentially analyze the proteome of key immunocompetent tissues: head kidney, anterior intestine, and liver following supplementation. Specifically, we used a label-free quantitative proteomic approach that applies a large-scale high-throughput LC-MS/MS based technology with high mass accuracy and sensitivity. Combing the differentially proteomic analyses result which annotated from Salmo salar database (Uniport Taxon 8030), 800~1000 proteins from different key immunocompetent tissues showed differential expressions. Computational and biological networks analyses were used to establish protein interactions and identify the key regulators (Figure 1).
Results showed that SNGM elevated fish immunocompetence by regulating key modulators of programmed cell death, phagocytosis, or antigen presenting pathways. Additionally, SNGM upregulated anti-inflammatory and antioxidant pathways, and induced changes associated to cell integrity, cell proliferation, and membrane transport. It was concluded that SNGM supports fish immunocompetence via both innate and adaptive mechanisms. This regulatory action is key in helping fish in dealing with production conditions and in reducing the impact of infections.