Molecular changes in the spleen of common carp (Cyprinus carpio) with chronic aeromonosis

Chronic aeromoniasis is one of the key pathologies of common carp under intensive aquaculture conditions, accompanied by latent impairments of immune and metabolic status. The aim of the study was a comprehensive analysis of the expression levels of genes related to immune status, antioxidant defense, and lipid metabolism of common carp ( Cyprinus carpio ) in the chronic form of the disease. A statistically significant decrease in the expression of pro-inflammatory cytokines il-1β (by 18.5 times), il-8 (by 12.7 times), and il-4 (by 7.1 times) was established against the background of a tendency toward an increase in il-12 and ifn-γ, indicative of a compensatory shift toward a cellular immune response. The identified statistically significant suppression of the expression of antioxidant defense genes sod1 (by 58.7%), cat (by 5.9 times), and the lipid metabolism gene fasn (by 14.6 times), combined with a tendency toward an increase in pparα, may indicate a switch in cellular metabolism toward β-oxidation of fatty acids. The totality of the obtained data suggests that immune deficiency in chronic aeromoniasis is attributable not so much to the direct action of Aeromonas spp . as to the depletion of the antioxidant and bioenergetic resources of the organism. At the same time, in some cases, this condition may be caused by activation of the cellular immune response, representing an adaptive but insufficient reaction of the organism.