Fe is an extremely important micromineral for the physiological activities of fish, such as O2 transport and antioxidant activities. The minimum nutritional requirement in Fe for maintenance of tilapia erythropoiesis is 60 mg Fe/kg and of 85 mg Fe/kg. These requirements are unclear as to the form of mineral used. This lack of information is due to the various rearing practices, ingredients used in nutrition and growth life stages.
This study aimed to evaluate the effects of dietary iron (Fe) on growth performance, digestive indices and biochemical parameters of tilapia juveniles fed with 60 and 85 mg/kg and two forms of Fe (organic and inorganic). Fish (16.57 ± 2.25 g) were feed three times a day, during 7 weeks, when 400 fish were distributed in 20 tanks (240 L, 20 fish each). The experiment was composed by 5 treatments, in a completely randomized design: basal diet (BD), without Fe inclusion in mineral mixture, 60 Inorganic, 60 Organic, 85 Inorganic and 85 Organic. Increase in dietary Fe organic form improves growth and biochemical parameters of tilapia. The Fe organic improves relative weight gain (261.34%), final weight (61.73 g) and biomass (1254.55%). Fe organic increases somatic digestive index but hepatosomatic index was highest in fish feed with 85 Fe inorganic. The glucose and ammonia of liver from tilapias increase in fish feed with Fe organic. This concluded that inclusion of Fe organic compound and level of 85 mg/kg is more efficient for juveniles of Nile tilapia.