Aiming to evaluate the effect of increasing levels of fat in the ration on performance, speed of food pass, consummates of ration and corporal fat, it were used 168 Nile tilapia fingerlings, reverted, with average weight of 1.24 ± 0,03g and average size of 4.10 ± 0.30 cm, allotted to 24 aquariums, of 50 L of useful volume, in a completely randomized design with six treatments and four replicates, where the aquarium with seven animals was considered experimental unit, for a period of 40 days. The temperature was kept in 27.2 ± 0.6ºC for heaters of 100W with thermostat and constant aeration. Diets were formulated to be isonitrogen, isoenergy and isoamino acidic for lysine and cystine + methionine, varying how much to the level of fat (3.0, 4.8, 6.6, 8.4, 10.2, and 12.0%). They had been evaluated the effect of the level of fat on the averages of the weight gain (GP), feed conversion (CA), tax of protein efficiency (TE), consumption of ration (CR), speed of food pass (VP) and corporal fat (GC). The GP, TE, CA had decreased linearly as the dietary level of fat increased, while GC increased, the CR did not present difference between the treatments, the VP presented a quadratic effect with point of minimum in 6.0% of fat in the ration. To reverted Nile tilapia fingerlings it is recommend 3.0% as fat level in the diet and was show a better starch utilization like energy source than fat in this specie.
fat; fingerlings; Nile tilapia; nutrition; Oreochromis niloticus; starch
