Effect of Periphyton and Supplementary Feeding on Growth Performance and Nutritive Physiology of Nile Tilapia, Oreochromis niloticus, and Pearlspot, Etroplus suratensis, Under Polyculture

ABSTRACT Growth performance of Nile tilapia, Oreochromis niloticus, and pearlspot, Etroplus suratensis, under polyculture was studied in inland saline groundwater ponds. Three treatments (1–3) each in replicate of two were maintained: In Treatment 1 (substrate ponds), bamboo poles as additional substrate were provided for the development of periphyton, while in Treatment 2 (fed ponds), no additional substrate was provided; however, the fish were fed on supplementary diet (40% CP). Treatment 3 served as control, where neither the fish were fed on any supplementary diet, nor any substrate provided in the ponds. Irrespective of the treatment (duration 90 days), ponds were fertilized with cow-dung at 7,500 kg/ha/year. Results revealed significantly (P < 0.05) higher fish growth in Treatment 1 due to the provision of additional substrate compared with diet (39%) and control (102%) ponds. The exponential value of “n” for both the fish species was higher (n = 3.2) in ponds provided with additional substrate than...