Preliminary study on the utilization of aqueous bark extracts of Khaya ivorensis in diets of Clarias gariepinus fingerlings

Abstract

Mortality of fish seeds is recognised as one of the major factors responsible for serious economic losses in fish culture business. A preliminary investigation on the effects of aqueous extracts of dried African mahogany, Khaya ivorensis bark on the growth, survival, haematology and histology of Clarias gariepinus fingerlings was conducted. A total of 135 C. gariepinus fingerlings (1.41±0.03 g/fish) were randomly allocated into three treatments, T1 (Control), T2 and T3, and fed with three different diets (40% CP) D1, D2 and D3 containing 0g/L, 25g/L and 50g/L aqueous extracts of K. ivorensis bark respectively. The experimental fish were fed ad-libitum for a period of 28 days in rectangular plastic containers (15x25x30cm3 ) and water exchange was done daily. Experimental data were analyzed for statistical differences in the growth, survival indices, haematology and histology of experimental fishes using analysis of variance (ANOVA). There was no significant difference (p>0.05) in mean weight gain of Control (2.91±0.68g) and T2 (2.20±0.20g) but T3 (1.79±0.39g) was significantly low. There was a significant difference in the survival (S) of experimental fish with the S (%) values of 73.67±13.50, 68.67±16.50 and 57.00±10.00 for T2, T3 and control respectively, no significant different in the feed conversion ratio (p>0.05) in the experimental groups. The haematological characteristics of all experimental fish were not significantly different, though the packed cell volume, PCV (%), haemoglobin count, HB (g/dl) and red blood cell, RBC (million/mm) were in the order T2˃T3˃Control having mean values of 22.71±4.5˃21.67±5.1˃19.67±1.53 (PCV); 22.67±4.51˃2.67±6.51˃19.67±1.53 (HB) and 2.09±0.47>1.99±0.57>1.73±0.13 (RBC) for T2, T3 and control respectively. The white blood cell, (No/mm) was highest in T1 (4.03±0.25) and least in T3 (3.67±1.35). Although there was no degeneration, the histological characteristics of liver of the experimental fish ranged from moderately diffused to fewer hepatocytes when compared to the normal liver, of the control. It is therefore concluded that Khaya ivorensis bark can be included in the diet of Clarias gariepinus fingerlings at 25g/L aqueous extract for good growth and high survival rates of fish under culture Keywords: Medicinal herbs, Extracts, African catfish, Fish culture