Evaluation of the effect of different levels of cotton seed meal on the performance and body composition of piavuçu (Leporinus macrocephalus) fry

Abstract

The performance and body composition of piavuçu (Leporinus macrocephalus) fry fed on diet with different inclusion levels of cotton seed meal í  CM: 0; 7; 14; 21; and 28% were evaluated. The experiment, done at the Aquaculture Laboratory of the State University of Maringá, lasted 54 days. Two hundred and fifty fry with initial weight 0.58 ± 0.18 g, initial length 3.69 ± 0.39 cm, and approximate age 35 days were distributed in 25 tanks of 250 L each one, in a totally randomized design, with five treatments and five replications. Pelleted diets contained 28% protein and 3,000 kcal of digestible energy. Mean values of temperature, dissolved oxygen, conductivity and pH during the experimental period were, respectively, 23.10 ± 0.23°C; 6.94 ± 0.53 mg/L; 197.55 ± 15.01 µS/cm; and 8.26 ± 0.23. No significant effect (P > 0.05) was detected in final weight, weight gain, final length, apparent food conversion, survival, carcass yield and percentage of fat in carcass when different treatments were given. Protein efficiency rate and protein percentage in the carcass showed a linear decrease in proportion to the increasing of CM inclusion levels. On the other hand, carcass ash and phosphorus increased linearly. Condition factor, dry matter and carcass calcium presented a quadratic effect, with maximum point in 17.43%; 13.61% and 26.92% of CM, respectively. It is suggested the use of 28% of cotton seed meal inclusion in the diet of the fry of piavuçu (Leporinus macrocephalus), without affecting the performance of the animals.