Haematological responses to stress of transportation and acclimation on the African catfish, Heterobranchus bidorsalis (Geoffrey, Saint Hilare)

摘要

Stress due to transportation and one week laboratory acclimation on the African catfish,procured from New Calabar River, Aluu in Rivers State of Nigeria causedsignificant reduction of Red Blood Cell (RBC), Blood Platelet (BP) counts, Packed Cell Volume (PCV)as well as haemoglobin contents (HC ) p<0.05 Conversely, stress of transportation and acclimation ledto significant elevation of total leucocyte (TL) counts, mean corpuscular volume (MCV) indices, bloodosmolality and glucose levels (p<0.05).The reduction in erythrocyte and thrombocyte counts is as aresult of reduced activity of haematopoietic organs due to stress of transportation and acclimation. Theelevated glucose and white cell counts is attributed to alarm reaction, preparing the fish to defend itselfagainst invading pathogens. Consequently, the body builds up a reserve of energy which ought to beexpended. The stress of transportation and acclimation (handling, sorting, injury, overcrowding,) andpoor water quality normally damage the mucous or slime layer that surrounds the fish. Under such acircumstance, being a freshwater species, absorbs much of the acclimation water and thiscontributes substantially to the reduced haematocrit and elevated osmolality observed.