EFFECT OF PROTEIN LEVELS ON GROWTH PERFORMANCE AND ECONOMICAL EVALUATION OF NILE TILAPIA (Oreochromis niloiicus)

Abstract

S ix approximately isoenergetic diets were formulated with protein levels from 20% to 45% in increments of 5%. The effects of varying dietary protein level on growth performance and economic efficiency were studied. The best growth rate was obtained with 30% dietary protein, followed by the diets containing 35,40, 45,25 and 20% protein, respectively. Feed conversion ratio was improved with increasing dietary protein levels up to 30%. Protein efficiency ratio was decreased with increasing dietary protein levels. Body protein was increased with increasing dietary protein levels up to 45%. There was an inverse relationship between the body moisture and lipid contents. Dietary protein levels did not affect the body ash content. From the economical point of view, the highest net return percentage of the total costs was 110.3% as recorded by the 3.0% Protein; followed by 102.4 % (25%. Protein) 99.4% (20%. Protein); 94.1 % (35%. Protein); 59.0 % (40%. Protein) and finally 48.6 % for (45%. Protein). The optimum dietary protein level for Nile tilapia (weighing 20g) was 30% and the feeding rate was 3% of body weight.

Evaluation of five commercial diets used for fish feeding in Basra governorate, southern Iraq

“…PER values increased significantly with increasing of dietary protein in the diets up to 30%, then reduced significantly when the dietary protein level was increased to 46%. Similar results were reported in common carp fingerlings (Ahmad et al, 2012), goldfish fingerlings (Souto et al, 2013), Nile tilapia fingerlings (Eid et al, 2003) and Kutum fingerlings (Ebrahimi and Ouraji, 2012). Rice et al, (1994) mentioned that the PER values are reduced when protein levels in the feed are either insufficient or are in excess, optimum protein content in fish feeds is species specific and occurs when PER is maximized.…”