Feeding strategy induces compensatory growth in Heros severus fingerlings, an Amazonian ornamental fish

Abstract

The aim of the present study was to evaluate the compensatory growth of severum (Heros severus) fingerlings fed inert diet for 30 days, after 13 days of larviculture at different feeding rates. The production cost with Artemia nauplii was also evaluated. For that purpose, a growth trial was performed with 400 severum post-larvae, distributed in twenty aquaria (1 L) at density of 20 post-larvae L−1. The experiment was conducted in a completely randomized design with five treatments and four replicates. For 10 days, the post-larvae received Artemia nauplii at different feeding rates: 100, 150, 200, 250 and 300 nauplii post-larvae−1 day−1. Subsequently, three days of food transition to an inert diet was performed. After this period, the severum stocking density was halved and the fish received inert diet for 30 days. The post-larvae fed with 200 Artemia nauplii post-larvae−1 day−1 presented the best results of final length, length gain and specific growth rate for length. On the other hand, post-larvae fed with 300 nauplii post-larvae−1 day−1 presented the highest results for final weight, weight gain and specific growth rate for weight. The average cost of using Artemia nauplii incresed directly with the increasing amount of nauplii supplied. The fingerlings presented best results of final weight and final length when received 250 nauplii post-larvae−1 day−1 during the larviculture. The weight gain of fingerlings did not differ for fish initially fed with 150–300 Artemia nauplii post-larvae−1 day−1, proving that the fingerlings expressed partial compensatory growth. The specific growth rate for length and weight were higher in fingerlings initially fed with 100 Artemia nauplii post-larvae−1 day−1, however, the survival rate was lower in fingerlings fed that amount of Artemia nauplii. Therefore, it is recommended 150 Artemia nauplii post-larvae−1 day−1 during the larviculture of severum to induce partial compensatory growth and reduce cost.