Effects crude protein levels on female Nile tilapia (Oreochromis niloticus) reproductive performance parameters.

The goal of the present work was to study the reproductive performance of Nile Tilapia (Oreochromis niloticus) female broodstock fed diets containing different levels of crude protein (CP). Two hundred and forty Nile tilapia (O. niloticus) were used at an average age of 30 months, with 180 females and 60 males. The broodstock were lodged separately in masonry tanks with continuous water flow. The females were stocked in thirty tanks with dimensions of 8 m(3) in a completely randomized design consisting of five treatments and six replications. The treatments consisted of five diets with different levels of CP (32, 34, 36, 38 and 40%) and with digestible energy per gram of protein of 9.5 kg of feed. The crude protein (CP) levels positively influenced (p<0.05) reproductive parameters (female relative and absolute fecundity, egg diameter, fasting larvae survival capacity), the somatic indexes (gonadosomatic (GSI), hepatosomatic (HIS), viscerosomatic (VSI)), total plasma protein, albumin and triglycerides. There were no significant differences (p>0.05) observed with regard to spawning weight and female weight. The reproductive parameters studied in the present research indicate that diets formulated with 38% CP with digestible energy per gram of CP of 9.5 were the best diets for tilapia females during the reproductive period.