Haematology, serum biochemistry and condition factor of the African snakehead fish, Parachanna obscura from Nigeria’s hydrologic areas
Rapid change in the conservation status of Parachanna obscura from least concerned to endangered species raises concerns over the health of the natural populations of this stock in Nigeria. This study therefore investigated the haematology, serum biochemistry and condition factor of P. obscura from Nigeria's freshwater environment to assess their wellbeing. All eight hydologic areas in Nigeria were purposively selected while one river in each of the basins was randomly chosen for sampling of P. obscura. These randomly selected rivers were from Anambra (Niger South), Imo (Eastern south) , Ibbi (Upper Benue), Kaduna (Niger Central), Katsina Ala (Lower Benue), Hadejia (Lake Chad), Ogun (Western Littoral) , and Sokoto (Niger North) rivers. Fish samples were collected quaterly for a year from fishermen's catch. One-way ANOVA and Duncan's Multiple Range Test were employed for data analysis. Percentage parked cell volume, lymphocytes, neutrophil and monocytes as well as haemoglobin and red blood cells were not significantly different (p>0.05) across populations. However, other haematologic parameters differed significantly among the populations. Samples from river Ibbi had significantly higher levels of glucose (47.75±3.22 mg/dL), aspartate aminotransferase (42.25±2.72 U/L), alanine aminotransferase (33.25±2.14 U/L) and blood urea nitrogen (1.91±0.31 mg/dL). Condition factors averaged 0.81±0.01. The present study showed that measured haematologic and serum biochemistry parameters as well as the condition factor were within normal reference values for P. obscura or similar tropical fish species reference values. Therefore, other causes of the decline in population of this species in Nigeria should be investigated.
Keywords: Parachanna obscura, Nigeria's freshwater environment, Population decline, Endangered tropical fish species.