Protein requirement of juvenile mullet Mugil platanus
Feeding is one of the main costs of fish farming, it is important to develop studies that seek greater food efficiency to increase the success of the activity and also to reduce the impact of the emission of nutrients to the environment. Taking into account the potential for breeding the mullet Mugil platanus in the Southeast and South of Brazil and the lack of information about its nutritional requirements, the present work was carried out with the objective of determining the protein requirement for its juveniles. The mullets were fed five diets with three repetitions each, each unit consisting of a 50L tank with 50 juveniles with initial weight 1.17 ± 0.02 g and 4.34 ± 0.03 cm (mean ± SE). The five isocaloric diets were formulated to contain increasing levels of crude protein (CP) of 30%, 35%, 40%, 45% and 49% and 18,7 MJ/Kg of diet (metabolizable energy). Diets were offered until satiety 5 times a day for 35 days. The diets did not show significant differences (P> 0.05) for survival, feeding efficiency and body composition. The results indicated that the level of 35% CP was statistically higher (P> 0.05) in relation to weight gain, food intake and specific growth rate than that of dietary mullets with the highest protein level. The protein requirement for mullet juveniles was estimated at 35.8% CP.