Ontogeny, morphometry and ultrastructural analysis of the lymphoid organ of the Pacific white shrimp Litopenaeus vannamei (Boone, 1931)
One of the obstacles that shrimp farming presents is the occurrence of diseases, which cause high economic losses and can reach the entire population of the crop. In crustaceans, because they do not present an immunological memory, the prevention of diseases becomes more difficult, since they have an innate immune system, eliminating pathogens in an unspecific way. There are several systems involved in the nonspecific system of penises, which may be humoral, cellular, physical and chemical factors. The lymphoid organ is considered an organ with participation in the immunological processes. It is currently believed that the lymphoid organ is a site of hemocyte maturation and may be directly involved in the immunological activation of shrimp. Thus, the objective of this work is the ontogeny, morphometric and ultrastructural quantification of the lymphoid organ in the white Pacific shrimp Litopenaeus vannamei. The results indicated the appearance of the organ in post larvae 6, being found phagocytic capacity at the end of the larviculture period. Data also indicate the affections of the lymphoid Organ cultured in clear water systems and Bioflocos, being more developed in the BFT systems. With the present work we can affirm the participation of the lymphoid organ in the immune system of L. vanammei shrimp, especially in the process of phagocytosis.