Hematology and parasite associated to Oreochromis niloticus raised in floating cages one lake Toho-Todougba in Southern Bénin

The physiology of fish blood is an important factor in assessing fish health. In this snapshot study, haematological constants and the degree of parasitism were determined on a sample of 56 Oreochromis niloticus individuals in private fish farming facilities on Lake Toho-Togbadji. Two sampling campaigns were carried within 15 days, both to assess the physico-chemical quality of the water with such parameters (pH, Temperature, Dissolved Oxgen and conductivity) and the fish catches. Blood samples were taken immediately from the fish in order to determine haematological constants like Haemoglobin rate, Haematocrit, Number of red cells, and derived. The fish sample was then placed in cool storage for the laboratory. For each individual, the total length was measured and the fish dissected. Parasites were investigated using a magnifying glass and optical microscope. Epidemiological parameters were also calculated. The results showed that fish had interesting haematological characteristics. Four groups of parasites were collected, including one ectoparasite and three endoparasites. Overall prevalence was 69.64%, with a strong male dominance. Cestodes were mostly abundant, while myxozoa was found in only 7% of fish. The health of the fish from a haematological point of view is not a cause for concern, despite the lake's enclosing nature. Despite the high parasite prevalence, there was no great diversity of parasites. A correlation between these different haematological and parasitic variables is conceivable for relevant conclusions on the reasons for the wild mortality sometimes observed on the lake Toho-Todougba in Southern Bénin.