Abstract:
The effects of replacing soybean meal with cocoyam leaf (Colocasia esculenta) meal on the growth and plasma enzymes profile of African catfish (Clarias gariepinus) juveniles were investigated in a feeding trial that lasted for 56days. C. esculenta leaf meal was used as a replacement for soyabean protein fraction in a 40% crude protein (CP) diet at 0% (CYL0) (control), 30% (CYL30), 40% (CYL40), 60% (CYL60) and 80% (CYL80). One hundred and fifty C. gariepinus juveniles (mean weight 31.5 ± 0.94g) were randomly distributed into glass aquaria tanks at 10fish/tank in triplicate treatments of five and were fed twice daily at 8:00-9:00hrs and 16:00-17:00hrs. The mean weight gain, specific growth rate, protein efficiency ratio and feed efficiency ratio decreased with increasing levels of C. esculenta leaf meal in the diets and there were significant differences (P<0.05) in the values of the parameters of fish fed the control diet (CYL0) and treated feed (CYL30 - CYL80). Haematological indices showed that packed cell volume (PCV), white blood cell (WBC), differential count, Mean Corpuscular Haemoglobin Concentration (MCHC), Mean Corpuscular Haemoglobin (MCH), and Mean Corpuscular Volume (MCV) were not significantly affected. The blood plasma enzyme profile revealed a difference (P<0.05) in the Lactic Dehydrogenase (LDH) and, Glutamate Oxaloacetic Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT), Acid Phosphatase (APT), total protein and globulin. All fish fed diets with the cocoyam leaf meal had significantly higher total protein, globulin and glutamate pyruvate than the fish fed control diet, and the values of these parameters increased with increasing levels of the cocoyam leaves meal. The apparent digestibility coefficient (ADC) of nutrients ADCprotein, ADClipid and ADCenergy indicated slight variations (P>0.05) as dietary treatment effects. The carcass and mineral compositions differed marginally across all treatments. In summary, cocoyam
leaves meal can replace soybean meal in the diets of African catfish but other processing methods for cocoyam leaves can be explore to reduce the antinutrients in these leaves which inhibit growth
