Evaluation of marine fish viscera as a protein source in diet for juvenile African catfish Clarias gariepinus (Burchell, 1822) reared in concrete tanks

Abstract

The goal of this study was to evaluate the suitability of marine fish viscera (MFV) as an alternative protein in diet for juvenile Clarias gariepinus. Three isonitrogenous (43% crude protein) and isoenergetic (gross energy 20 kJ.kg-1) diets were formulated to contain 0% (D0, control diet), 30% (D30) and 50% (D50) of MFV, as fishmeal (FM) substitutes. The diets D0, D30 and D50 were compared with the reference commercial diet Coppens® developed for African catfish. Fish (initial body weight: 8.0 ± 0.3g) stocked at fifty-five per tank where fed at satiation in twelve (4 x 3 replicates) tanks for 42-day in a recirculating water system. At the end of experiment, final weight (96.6 g - 111.0 g), daily weight gain (2.1 g/day - 2.5 g/day), Specific Growth Rate (5.7%/day - 6.3%/day), feed conversion ratio (1.1-1.3), protein efficiency ratio (1.8-2.2), yield (4.7 kg/m3 - 6.1 kg/m3) and annual production (41.1 Kg/m3/year - 53.1 Kg/m3/year) did not vary significantly until 30% MFV in diet (P > 0). Values in fish fed 50% MFV were significantly lower (P ˂ 0). Cost-benefit analysis show a considerable reduction in cost of production of one kilogram fish, to about 79.34% and 76.03% with fish fed 30% and 50% MFV, respectively, compared to commercial diet. Thus, the MFV should be included up to 30% in diet for C. gariepinus juvenile without negative influence on growth performance, feed utilization and production. The results encourage more investigations in promoting of that environmental-friendly ingredient in the production of C. gariepinus in Benin small-scale farms.