Effects of fish meal replacement on production and economics of tilapia monoculture systems in ponds

Abstract

The effects of partially replacing fish meal with locally available mustard oil cake (MOC) were evaluated on production, feed utilization, greenhouse gas (GHG) emissions, and economic returns of monosex tilapia (Oreochromis niloticus) cultured in nine farmer-managed ponds at Harian of Paba Upazila, Rajshahi, Bangladesh. The study addressed rising fish meal cost, import dependency and the need for affordable, locally sourced, climate-smart feed alternatives. Three isonitrogenous diets (28% crude protein) were tested in a randomized complete block design with three replicates: T1 (30% fish meal, 25% MOC; 0% replacement), T2 (25% fish meal, 30% MOC; 16.7% replacement), and T3 (20% fish meal, 35% MOC; 33.3% replacement). Fish were stocked at 50,000 ha-1 across treatments. Fish meal replacement significantly (p