Evaluation of Guar meal as a dietary protein source for Nile tilapia (Oreochromis niloticus) reared in hapa-in-pond system

Abstract

Background: This study was carried out to investigate the effect of Guar Meal (GM) as a protein source for Nile tilapia (Oreochromis niloticus) fingerlings. Methodology: Six isonitrogenous (280 g crude protein kg−1), isoenergetic (19 MJ GE kg−1) test diets were prepared. The GM was incorporated into the diets at 0, 20, 40, 60, 80 and 100% of dietary soybean meal (SBM). The diets were fed to triplicate groups of all-male Nile tilapia juveniles (20 g) reared in hapa-in-pond system, at 2-3% of their body weight, twice a day for 105 days. Results: The results indicated that fish performance was excellent at all GM inclusion levels. However, growth rates significantly decreased with increasing GM levels beyond 20%. Feed Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and Protein Productive Value (PPV) were significantly retarded (p<0.05)with increasing dietary GM up to 20% level. Further increase in GM up to 100% level did not result in any further retardation in feed utilization efficiency. Conclusion: The cost/benefit analysis including Incidence Cost (IC) and Profit Index (PI) of the test diets indicated that GM-based diets, even at 100% substitution were economically better than the control, SBM-based diet. These results suggest that GM can totally replace SBM in Nile tilapia feeds.