C/N ratio control and substrate addition for periphyton development jointly enhance freshwater prawn Macrobrachium rosenbergii production in ponds

The present research investigated the effect of carbon/nitrogen ratio (C/N ratio) control in ponds with or without substrate addition for periphyton development on production of giant freshwater prawn. C/N ratios of 10, 15 and 20 were investigated in 40 m⁻² ponds stocked with 2 prawn juveniles (5.023±0.02 g) m⁻² with or without added substrates for periphyton development. The various treatment combinations of C/N ratio and periphyton substrate addition are abbreviated as 'CN10', 'CN15', 'CN20', 'CN10+P', 'CN15+P' and 'CN20+P', P representing periphyton substrate. A locally formulated and prepared feed containing 30% crude protein with C/N ratio10 was applied. Tapioca starch was used as carbohydrate source for manipulating C/N ratio and applied to the water column separately from the feed. Increasing the…