Preliminary evaluation of fermented castor (<i>Ricinus communis</i>) seed meal in the diets of <i>Clarias gariepinus x Heterobranchus bidorsalis</i> hybrid fingerlings

Abstract

The potential of using fermented castor seed (Ricinus communis) meal (FCSM) as a dietary protein source in the diets of hybrid Clarias gariepinus x Heterobranchus bidorsalis fingerlings was studied. FCSM level was increased at the expense of soybean meal (SBM) in isonitrogenous (30%) and isocaloric (metabolizable energy (ME) of 409.22Kcal/100g) diets. SBM was replaced at 0, 25, 50, 75 and100% levels by FCSM. Each diet was fed for 56 days to triplicate groups of fingerlings in a completely randomized design using floating hapas in an outdoor concrete cistern. Growth was best in the group of fingerlings fed the control diet, but this was not significantly (P<0.05) better than the group fed TD1 6.98% FCSM diet level; while it was least in the group fed 32% FCSM level. Every other growth and feed nutrient utilization parameter followed this trend. Survival was 60 to 86% and non-differential between the dietary treatments. Carcass protein significantly decreased with increased FCSM level, and carcass lipid showed inverse relationship with protein and moisture levels. Results showed that FCSM can be incorporated up to about 7% in the diet of the hybrid fingerlings. However, further studies are required on techniques of deoiling prior to fermentation and use of antioxidants.