Lapsi (Choerospondias axillaris ) is a large, deciduous fruit-bearing tree of Nepal. Fruit extracts of lapsi possessed high antioxidant activity. Therefore, our goal of the study was to evaluate the dietary effects of lapsi fruits extracts on growth performance and protein metabolism in rainbow trout (Oncorhynchus mykiss) . A total of 450 rainbow trout (37.24 ± 0.39 g) were randomly distributed into six groups with three replicates (25 fish per cage), fed six practical diets ( isonitrogenous diet 40% protein) such as control diet without the lapsi extract (D1) and the other five diets containing incremental level of lapsi fruits extract at the rate of 100 (D2), 200 (D3), 400 (D4), 800 (D5) and 1600 (D6) mg kg-1 . Fish were fed twice per day at satiation level for 90 days.
Results of the study showed that supplementation of lapsi fruits extracts significantly affects (P<0.05) the growth performance and nutrient utilization in fish. H ighest growth was observed in D4 (440 ppm) fed group whereas lowest value was found in control (D1) but feed conversion ratio (FCR) exhibited opposite trend. Growth results were concurred with protein profile content of serum (protein, albumin and globulin) in fish.
Conclusively, lapsi fruits can be used as an additive in trout diet to enhance the fish growth for sustainable aquaculture.
Keywords : Lapsi, rainbow trout, growth , protein