Comparative analyses of immune gene profiles and antioxidant capabilities in the midgut and liver of three species of grass carps (Ctenopharyngodon idella) following gut infection with Aeromonas hydrophila

Aeromonas hydrophila is an important etiologic agent, triggering an increased trend of disease outbreak in fish farming. In this investigation, we evaluated pathological response in the midgut and liver of three types of grass carps after gut infection. Severe pathological levels of tissue necrosis were observed in common grass carp (GC) and gynogenetic grass carp (GGC), but mild pathological symptom was detected in hybrid grass carp (DRGC), along with the dramatically increased number of goblet cells. Moreover, three types of grass carps showed upregulated levels of immune gene patterns and antioxidant abilities, whereas inflammatory cytokine expression levels in hybrid grass carp (DRGC) were lower than that of gynogenetic grass carp (GGC) and common grass carp (GC). These results suggested that DRGC may exhibit a disease tolerance against A. hydrophila-induced tissue inflammation.