Partial replacement of fishmeal with Spirulina platensis and Chlorella vulgaris and its effect on growth and body composition of African catfish Clarias gariepinus (Burchell 1822)

Abstract

The study examined the effect of partial replacement of fishmeal with Spirulina platensis (SP) and Chlorella vulgaris (CL) powder in the diets of African catfish Clarias gariepinus (Burchell 1822) fingerlings on growth performance and body composition. Nine diets (45.14-48.45% crude protein) consisting SP or CL as fishmeal replacement at zero (control), 12.5, 25, 50 and 75%, were fed to triplicate groups of 10 fingerlings (7.82±0.08 g) each for 56 days. The results showed statistically higher weight gain, specific growth rate, protein efficiency ratio, relative growth rate, Fulton’s condition factor (K) and a corresponding lower feed conversion ratio when the replacement of C. vulgaris was at 75%. Proximate analysis revealed a significantly greater carcass protein in the SP12.5% and the highest flesh lipid and gross energy in SP75% groups. Flesh lipid increased with increasing SP and CL levels. Polynomial curve estimation regression analysis revealed the optimum fishmeal replacement levels for best growth are at 68.5 and 69.4% for SP and CL, respectively. CL was found to be more efficient in terms of growth and effective feed utilisation than SP.