The purpose of this study was to look into the ability of a propolis-supplemented diet on some haematological indices and histological alterations in the gill, kidney, and testes of catfish (Clarias gariepinus) to cope with heat stress (HS), which could alter the physiology, homeostatic systems, and survival of catfish, indicating that the effects of heat stress on warrant further investigation.
In this study, male catfish were separated into three groups: control at 28◦C, HS group at 36◦C, and HS group at 36◦C supplemented with propolis for up to 21 days. The treatment group at 36◦C showed that, RBCs decreased considerably while WBCs did not decrease appreciably during the research period when compared to the control one. Microscopically, all tissues revealed changes in the morphological structure: the most massive difference in the gills was curving tips and edema, the most major change in the kidney was vacuolated tubular cells, and the most major change in the testes was a degraded cyst. However, the propolis group showed enhanced RBC and WBC counts, and most histological and histochemical markers were returned to the normal structure when compared to the control one.