Effect of Iron Amino Acid Chelate Supplemented Fish Feeds on Nutrients Composition of Spinach (Spinacia oleracea) in an Aquaponic System in Kenya

Aquaponics is an environmentally friendly production system involving reuse of waste and nutrients in production of fish and vegetables. Currently aquaponic system is the only solution for fish and plants production but one unique challenge is the maintaining of micro and macro-nutrient and the pH balance in the system. The study was conducted at the University of Eldoret for 119 days. A complete randomized design was used. The supplementation rates in fish diets constituted 30g, 20g, 10g and 0g Fe kg -1 respectively. Nile tilapia fry with a mean weight of 0.475 ± 0.025g and nine spinach (height 3 ± 0.131cm, 2 leaves) were stocked in 12 aquaria in an aquaponic system. 30g Fe kg -1 treatment exhibited higher minerals content than other treatments with Phosphorus 67.51 ± 2.42 mgL -1 , Zinc 9.06 8± 0.45 mgL -1 , Iron 5.2 ± 0.218 mgL -1 , Manganese 7.655 ± 0.344 mgL -1 , Total Nitrogen 11.248 ± 0.141mgL -1 and Sodium 7.218 ± 0.028 mgL -1 . There was improved water quality at 30g Fe kg -1 compared to other treatments. These results revealed that 30g Fe kg -1 iron amino acid chelate supplementation had better nutritional attributes as feedstuff for spinach growth than the three other dietary treatments. The study recommends the incorporation of 30g Fe kg -1 iron amino acid chelate in on-farm formulated diets for aquaponic system where complete diets are not easily accessible for small scale farmers.