Effects of feed restriction on compensatory growth performance of Indian major carps in a carp-prawn polyculture system: a response to growth depression

Effects of feed restriction on compensatory growth (CG) performance of Indian major carps, sediment loading and water productivity in a carp-prawn grow-out production system were examined. The overall growth and crop performance were in the similar line in both T-1 (regular feeding, 2 times a day) and T-2 (4-week feeding followed by 2-week no feed). However, between T-1 and T-3 (8-week feeding followed by 2-week no feed), there was a significant (P<0.05) variation in the overall growth and crop performance. This was probably due to the longer refeeding periods after cyclic food deprivation that successfully triggered compensatory growth response in T-3 (CG Index: 98-104%). Treatment-wise sediment load ranged between 59.2 and 69.6m(3)t(-1) biomass. Higher the apparent feed conversion ratios, higher was the sedimentation rate. Higher the feed input, higher were the water exchange requirement, total water use and consumptive water use index. Cyclic food deprivation and refeeding also helped in maintaining water quality due to the restricted feed input (10.5% in T-2 and 2.0% in T-3), thus minimizes the input cost and improves production efficiency. Keeping the growth and yield performance, water productivity and economic efficiency in view, T-3 is considered the best feed management protocol followed by T-2 and T-1.