Sustainability of Growth Performance, Water Quality, and Productivity of Nile Tilapia-Spinach Affected by Feeding and Fasting Regimes in Nutrient Film Technique-Based Aquaponics

Aquaponic systems offer an innovative approach to sustainable agriculture, where the interplay between fish and plant cultivation can be optimized. The choice of feeding and fasting schedules plays a crucial role in system efficiency and overall productivity. This study aims to investigate the impacts of various feeding and fasting schedules on water quality, and the growth performance of Nile tilapia, Oreochromis niloticus fingerlings, and spinach productivity in an aquaponic system based on the nutrient film technique (NFT). O. niloticus fingerlings with an initial weight of 13.47 ± 0.14 g were randomly stocked at a density of 6 kg/m 3 , and spinach plants (Spinacia oleracea) were included. The study employed a completely randomized block design with five replications. Various water quality parameters were monitored, and the effects of different feeding/fasting schedules on fish and spinach were assessed. The data revealed significant differences ( p < 0.05) in water quality parameters, all of which remained within acceptable ranges for aquaponic systems. The one-day feeding/one-day fasting treatment resulted in reduced final body weight, weight gain percentage, and specific growth rate, compared to other treatment groups ( p < 0.05). Higher levels of glucose and plasma cortisol were observed in this treatment. Economic efficiency was highest in the daily feeding treatment (40.05%), with no statistical difference ( p > 0.05) observed in the group subjected to three-day feeding/one-day fasting (39.03%). Spinach yield varied significantly between treatments ( p < 0.05), with the daily feeding treatment recording the highest yield (2.78 kg/m 2 ) and the one-day feeding/one-day fasting cycle having the lowest yield (1.57 kg/m 2 ). The findings suggest that the three-day feeding/one-day fasting regime in an NFT-based aquaponic system results in efficient nutrient utilization, higher productivity, and profitability for Nile tilapia. Additionally, this approach supports marketable biomass production for spinach. Different feeding and fasting schedules have distinct effects on water quality, fish growth, and spinach productivity in aquaponic systems. The three-day feeding/one-day fasting schedule emerges as an effective strategy for optimizing resource utilization and increasing overall productivity.