Optimization of dietary protein level for good aquaculture practice based carp fattening in ponds under drought prone area of Bangladesh

Good aquaculture practice (GAP) based carp fattening is a potential technique to obtain higher and safe fish production within shorter period in ponds of drought prone area. Sustainability this technique, however, constrained by high feed cost poor water quality. Therefore, as an overcoming effort, three diets (protein content 20%, 25% 30%) under different treatments (T1, T2 T3) were tested during January-June, 2020 carps (Catla, Gibelion catla; silver carp, Hypophthalmichthys molitrix; rohu, Labeo rohita; mrigal, Cirrhinus cirrhosis; carpio, Cyprinus carpio var. specularis) Rajshahi district, Bangladesh. Variation protein level had no significant effect on environmental parameters pond water. Combined yield was found vary significantly (P<0.05) among the treatments, while conversion ratio did not significantly. Although second degree polynomial regression analysis identified 28.50% dietary for optimal growth but difference between T3 total yield. However, highest cost-benefit obtained with diet containing suggested profitable pond.