Morphology and histology of head-kidney and spleen in Cromileptes altivelis

[Objective]The present experiment was conducted to investigate morphology and histology of head-kidney and spleen in Cromileptes altivelis to enrich basic data about comparative anatomy and histology of immune organs of C.altivelis,in order to provide theoretical basis for C.altivelis biology and its aquaculture.[Method]The head-kidney and spleen of C.altivelis were collected by conventional sampling method,and the paraffin sections of which were prepared and stained with HE.Then the microstructures of head-kidney and spleen of fish were observed under optical microscope.[Result]The results showed that,the head-kidney of C.altivelis was located in the back of esophagus and above intrathoracic pharyngeal retraction muscle,its surface was covered with a very thin layer of loose connective tissue capsule,belonging to lymphoid parenchyma,but with no obvious trabcula and nephron.There were red blood cell centers and leukocyte centers in head-kidney.And head-kidney was mainly composed of lymphoid tissue,blood vessels and sinusoids,and the melanin macrophage centers were found among them.In addition,spleen was located in posterior of stomach and anterior part of intestine,its surface was also covered with a very thin layer of fibroid connective tissue capsule but with no obvious trabecula,and mainly composed of red pulp and white pulp.The spleen contained large quantities of lymphocytes,haemocytes,granulocytes,ellipsoids and melanin macrophage centers.Many arteries,veins and nerve tract in parallel arrangement went along with each other in spleen.[Conclusion]Head-kidney is an important hematopoietic and immune organ for C.altivelis,and spleen plays a strong physiological function in hemofiltration and blood storage.