University of Nairobi

Abstract

The kidneys of four freshwater teleost fish Oreochromis niloticus, Micropterus salmoides, Cyprinus carpio and Clarias mossambicus and one marine teleost, Chanos chanos, representing Perciformes (O. niloticus and M. salmoides) Ostariophysi (C. carpio, and C. mossambicus) and Salmoniformes (C. chanos) were studied for qualitative and quantitative characteristics using materials fixed in situ by perfusion via the bulbous arteriosus into the entire renal arterial system. The kidneys of O. niloticus, M. salmoides and C. carpio were partially fused and those of C. mossambicus and C. chanos were completely fused. Partial or complete venous portal systems were present in all the species except O. niloticus. The renal lobule was centered on the intralobular artery and duct and delimited by efferent veins. The nephron of the fishes consisted of a renal corpuscle, the neck, proximal 1, proximal 2 and distal segments and the collecting tubule-collecting duct system. These parts of the nephric tubule were distinguished on the basis of their staining reactions and histological and ultrastructural characteristics. Intrarenal heamopoietic tissue was absent in the Perciformes teleosts but was abundant in the Ostariophysi and Salmoniformes. Interrenal tissue in the head kidney was arranged in cords around branches of the posterior cardinal vein. Rodlet cells have been described in the proximal tubule of the blackbass