Abstract

An investigation was carried out on the possibility of replacing fishmeal with graded levels of yeast single cell protein (SCP; 10, 20, 30, 40 and 50%) in isonitrogenous feed formulations (30% protein) in the diet of Oreochromis niloticus fingerlings for a period of 12 weeks. The control diet had fishmeal as the primary protein source. There were six treatments and four replicates. The result indicates that the 50% yeast SCP diet gave the best in growth response with percentage weight gain (PWG) of 6.04, specific growth rate (SGR) of 0041, daily growth rate (DRG) of (0.0088) and feed conversion ratio (FCR) of 1.94. There was however no significant difference in growth parameters and feed conversion ratio between treatment (p > 0.05). The proximate examination of the carcass composition of the whole fish body showed that the 50% yeast SCP fed fish had the highest percentage of body protein (55.35%), but with a lower amount of fat at the end of the feeding trial compared to the control. There was however no significant difference in carcass protein and fat content between treatments (p > 0.05). It could therefore be concluded that yeast SCP can successfully replace fishmeal up to 50% level with 0.25% dietary methionine supplementation in a 30% protein diet for O. niloticus fingerlings with no significant difference in fish performance (p > 0.05).

Key words: Tilapia, yeast single cell protein, growth, carcass composition, feeding trials.

Abbreviation

SCP, Single cell protein; CRD, complete randomization design;RGR, relative growth rate; RWG, relative weight gain; PWG, percentage weight gain; SGR, specific growth rate; DGR, daily growth rate; DRF, daily rate of feed intake; FCR, feed conversion ratio; NFE, nitrogen free extract.