It was studied the effect of the addition of C18:2n6, by the inclusion of corn oil, in diets with different levels of crude protein (CP) on the process of gonad maturation in surubim, Pseudoplatystoma corruscans. Survival rate, weight x length ratio, condition factor (K), and gonadossomatic index (GSI) were evaluated. The experiment was carried out from March 2004 to February 2006, using 12 cages distributed in six tanks, with 20 fishes per cage. Three treatments (T) were: T1 28% CP; T2 28% CP + 5% corn oils, and T3 40% CP. No effect of the diet was observed on growth in the 1st and 2nd years of age, with a slightly superior growth of T3 fish. The survival rates were superior to 77%. It can be inferred that the offered diet did not cause histomorphological alterations during the process of gonadal maturation of this species. However, the GSI and the K were slightly advanced and superior in the animals fed the diet supplemented with corn oil.
surubim; broodstock; linoleic acid; protein; cative
