Effects of dietary protein levels on proximate, haematological and leukocyte compositions of <I>Clarias gariepinus</i>

Abstract

Study was conducted to evaluate effects of feeding different dietary protein levels on haematological profile and leukocyte population of Clarias gariepinus using net-hapa system. Catfish fingerlings (mean weight 4.50± 0.01g) were randomly stocked at 20 fish per net-hapa (1m³). Five experimental diets with crude protein of 40.00%, 42.50%, 45.00%, 47.50% and 50% were formulated and fed to the fish for 24 weeks. Blood samples were collected and examined for white blood cell (WBC), red blood cell (RBC), haemoglobin (HB), haematocrit (HCT) mean corpuscle volume (MCV) mean corpuscle haemoglobin (MCH) mean corpuscle haemoglobin concentration (MCHC), Platelet (PLT), leukocytes, lymphocytes, neutrophils, monocytes, eosinophils and basophils. Results revealed a reverse relationship between haematological indices of fish and dietary protein inclusion levels. The best WBC (207x10³count/μl), RBC (4.9x10⁶count/μl), Hb (19.0g/dl), HCT (41.0%), MCV (149.0fL), MCH (49.35pg), MCHC (40.6g/dl) and PLT (134.0 x 10³ count/μl)) were presented in fish fed 40% protein diets. Results of leucocyte population did not follow any particular trend. A high positive correlation (r>0.9000; p<0.05) existed between the treatments in RBC, WBC, and Hb. The results conclude that 40% dietary protein inclusion is recommended for C. gariepinus for sound and healthy condition in floating net-hapa system.

Keywords: Dietary protein, haematology, leucocyte, catfish health