Assessment of relative contributions of natural and artificial feed in Oreochromis niloticus according to growth stage in integrated rice–fish farming systems in Côte d’Ivoire

Rice–fish farming, which combines rice cultivation with fish rearing in the same environment, represents a promising agroecological solution for sub-Saharan Africa in response to growing food and economic challenges. Although this integrated system enhances the use of natural resources, quantitative data on the dietary intake of natural and artificial feed in Oreochromis niloticus remain limited, particularly across different growth stages. This study aims to address this gap by evaluating the nutritional contributions of both feed types in juvenile and adult fish, with the goal of optimising feeding strategies in rice–fish systems. The experiment was carried out at the Bonoufla-Kouadiokro site in Côte d’Ivoire, using nine earthen ponds. Fish were provided with a practical diet formulated from soybean meal, cottonseed meal, rice bran, and maize bran. Individuals were classified into two weight categories: juveniles (26.58–28.15 g) and adults (246.58–251.32 g). Stomach contents were analysed over two 24-hour cycles, taking into account nycthemeral rhythms and growth phases. Results revealed a strong reliance on natural resources, with Euglenophytes and Rotifers dominating the diet. Among juveniles, the distribution between natural and artificial feed was balanced (≈47–53%), whereas artificial feed predominated in adults (≈67%). Cycle 2 was characterised by higher total intake, improved utilisation of artificial rations (up to 72.93% consumed), and reduced waste. These findings underscore the importance of adjusting feed rations according to physiological stage to enhance feeding efficiency and sustainability in integrated rice–fish farming systems.