Effect of Protein Levels on Growth Performance, Feed Utilization and Economic Evaluation of Fingerlings Nile Tilapia Fingerlings under Biofloc System

Document Type : Original Article

Abstract

The current experiment was designed to test the effect of crude protein content (19, 25 and 30% C.P.) on growth performance of monosex Nile tilapia (Oreochromis niloticus) fingerlings on clear and biofloc system. Three dietary protein levels (19, 25 and 30% CP) were used under biofloc system (no water exchange) in comparison with clear system three replicates for each treatment. The experiment was lasted for 84 days. The daily ration was 5% of the total stocked biomass divided into two equal amounts and offered two times a day (8.00 and 12.00). Fish in each treatment was weighed every 15 days and the amount of the daily allowance feed was readjusted accordingly. The C: N ratio was maintained at 15: 1 by daily addition of rice bean as an organic source of carbon. For biofloc treatments, rice bran was activated heterotrophic bacteria growth. Rice bran was dissolved in water at dry feed to molasses ratio of 1:1 on a daily basis in order to develop biofloc and nourish heterotrophic bacteria. The highest final body weight (FBW), weight gain (WG) and specific growth rate (SGR) values were recorded for fish fed 30% (DP). Biofloc system (BS) showed superiority over clear system (CS) for FBW, WG and SGR values. It could be concluded that 30% crude protein was the best in terms of growth performance, feed utilization and economic evaluation for monosex Nile tilapia fingerlings under this experimental conditions.

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