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 (1m 3). 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 (207x10 3 count/μl), RBC (4.9x10 6 count/μl), Hb (19.0g/dl), HCT (41.0%), MCV (149.0fL), MCH (49.35pg), MCHC (40.6g/dl) and PLT (134.0x10 3 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.

The study evaluated proximate compositions, length-weight relationships, condition factor and the survival rates of hybrid catfish, Clarobranchus (Clarias gariepinus (male) X Heterobranchus bidorsalis (female) reared at different densities in tarpaulin tanks. Fish were stocked at densities of 25, 50, 75 and 100fish/m3. Each treatment was replicated three times. Fish were fed with commercial catfish feed (45% crude protein) at 5% body weight for 84 days. Length and weight data collected were analyzed with FISAT software using the ELEFAN package to estimate relationship in body parameters. The mean exponent (b) for total length was 3.07 for fish reared at 75fish/m3. This showed positive allometric function, indicating that the species gets plumper as it grows larger. The regression line indicated a significant relationship (r = 0.9112; p < 0.05) with the equation W = 5.3783L3.0700. This showed that there was a high and significant correlation between the various total length and weight of Clarobranchus. Fish condition was best at 75fish/m3 density. There were no variations (p<0.05) in fish survival rates and whole body compositions. The results suggested that 75fish/m3 provided optimum environment for rearing Clarobranchus. Keywords: Hybrid, catfish, condition factor, survival, nutrient values

The study examined helminth parasites of cultured Clarias gariepinus and Tilapia zillii in Uyo, Akwa Ibom State. A total of 60 fish samples (30 each of C.gariepinus and T. zillii) were subjected to parasitological examinations. Results revealed a total of 47(78.33%) fishes infected with various species of parasites: Nematodes (Camallanus polypteri, Paracamallanus cyathopharynx, and Procamallanus laevionchus), Cestodes (Polyonchobothrium torulosus and P. clariae) and Trematodes (Dactylogyrus extensus and Glossiduim pedatum) in decreasing order of abundance. Out of the 60 fish samples examined, 47 were infected with 219 parasites: 142(64.84%) nematodes, 40(18.26%) cestodes and 37(16.89%) trematodes. A total of 159(72.60%) parasites were recovered from C. gariepinus out of which 103(64.78%) were nematodes, 19(18.45%) were cestodes and 37(35.92%) were trematodes. While 60(27.40%) parasites were recovered from T. zilli, of which 39(65.00%) were nematodes and 21(35.00%) cestodes. No trematode was observed in the tilapia. The overall prevalence of parasitic infection was 78.33%. The results of chi square analysis showed that females of both species had significantly higher (P<0.05) prevalence of infection 27(84.4%) than males 20(71.4%). Also, C. gariepinus had higher infection rate of 25(83.33%) when compared to 22(73.33%) recorded in T. zillii. Key words: fish parasites, aquaculture, prevalence, C. gariepinus, T. zillii

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