Two trials were set up to evaluate the influence of different levels of dietary vitamin C supplementation on growth, performance, survival rate and resistance to low dissolved oxygen (LODO) concentration of piauçu fingerlings (Leporinus obtusidens). Trial 1 (105 days) evaluated the effect of diet supplementation with L-ascorbic acid (0, 50, 150, 250, 350, 450, 550, 650, 750, 850 mg of vitamin C/kg of diet) on weight gain and survival, in a completely randomized design. There was no significant differences among treatments with respect to weight gain (P > 0.4054) and survival rate (P > 0.5657). In Trial 2, groups of 10 fish of each replicate of Trial 1, were stocked in 20-L cages, in a randomized block design, and submitted to a 14-h LODO stress (1.0 mg DO/L). Fingerling survival rate was not significantly affected by LODO levels (P > 0.4032) up to 14 hours after stressing conditions ceased. In contrast to our results, data found in the literature show that dietary vitamin C supplementation significantly affects the studied parameters. Therefore, it is suggested that more extensive studies should be performed to determine dietary vitamin C requirements of this species.
Leporinus obtusidens; nutrition; vitamin C; stress