“…As time goes on, these investigations have evolved to various omics levels. Although investigations on the intestinal responses to Aeromonas infection have not yet been published, studies on skeletal muscle [ 27 ], gill and liver [ 28 ], skin [ 29 ], gonads [ 30 ], intestinal air-breathing function and nutrition uptake and gas exchange [ 31 , 32 ], have been investigated in loach fish. Despite the fact that the gut-associated lymphoid tissues (GALTs) should have played a significant role in disease resistance among the four fundamental physical barriers created by a fish (gill-associated lymphoid tissues, skin-associated lymphoid tissues, mucosa-associated lymphoid tissues, and gut-associated lymphoid tissues), no research has been done to examine the pattern of immune response in the gut of loach fish under any pathogen-stress.…”