Effects of Varying Dietary Protein Levels on Growth, Digestive Efficiency and Body Composition in Climbing Perch (Anabas testudineus) Fry

Background: The present study was investigated to evaluate the effect of varying levels of dietary crude protein on growth, digestive enzyme activity, digestibility and whole body composition of Anabas testudineus. Methods: Four iso-energetic diets were prepared at varying levels of dietary crude protein such as 25% (CP 25), 30% (CP 30), 35% (CP 35) and 38% (CP 38). A total of 300 numbers of fry (average fish weight - 0.56±0.05 g) were stocked in 12 tanks (25 fish/tank), randomly in triplicate conditions and fed with experimental diets at ad-libitum level for 60 days. Result: The study observed better growth performance and feed utilization in 35% and 38% crude protein fed groups. The highest weight gain (8.49±0.08 g) was observed in CP 38 dietary group, while the highest apparent digestibility coefficient of dry matter (72.24±0.27%), crude protein (82.44±0.52%) and crude lipid (84.59±0.62%) were also observed in the CP 38 dietary group. Protease activity was significantly (P less than 0.05) higher in the CP 38 dietary group, whereas amylase activity was significantly (P less than 0.05) lower in the CP 38 dietary group. Whole body composition improved with increasing protein levels, with the lowest crude protein content (13.61±0.04%) in the CP 25 dietary group. To conclude, 35% crude protein is recommended as optimal for climbing perch fry due to its cost effectiveness, efficient nutrient utilization and reduced environmental impact.