Estratégias alimentares na larvicultura do peixe ornamental amazônico Pyrrhulina brevis (steindachner, 1876): Concentração de presas e transição alimentar.

Abstract

Pyrrhulina (Pyrrhulina brevis) is a endemic fish from the Amazon basin with potential for ornamental fish farming, as it has morphological and behavioral characteristics appreciated in aquarium trade industry and attractive prices in the market. However, the available specimens are still obtained from extractivism and their production in captivity comes up against the scarcity of scientific information on feeding and productive management in larviculture. Thus, the objective of this study was to determine the adequate prey concentration, the ideal time of Artemia nauplii supply and co-feeding periods in the intensive larviculture of P. brevis. The first experiment was carried out in a completely randomized design, with five treatments and four replicates, for a period of 30 days. Five prey concentrations (P) were evaluated: P150f - 150 Artemia nauplii larvae-1 day-1, with a fixed amount throughout the experiment; and P50g - 50, P150g - 150, P250g - 250 and P350g - 350 Artemia nauplii larvae-1 day-1, with amounts corrected every six days of experiment, increasing 50% in relation to the previous level. The second experiment was carried out in a completely randomized design, in a 4x3 factorial design, with three replicates, for a period of 40 days. Four times of Artemia nauplii supply (T) (0, 10, 20 and 30 days, labeled T0, T10, T20 and T30) and three co-feeding periods (C) (0, 3 and 5 days, labeled C0, C3 and C5) were evaluated. At the end of the experiments, the growth performance, stress resistance to air exposure (10 minutes) and feedstock cost of the foods were evaluated. In the first experiment, the P. brevis larvae fed with increasing prey concentration initial of 350 Artemia nauplii larvae-1 day-1 had better performance and stress resistance rate. The increase in the feedstock cost of the food was observed as the prey concentrations increased. In the second experiment, the P. brevis larvae fed with 20 and 30 days of Artemia nauplii supply had better performance and stress resistance rate. The performance was higher in P. brevis larvae fed with 3 and 5 days of co-feeding, while the co- feeding periods did not affect the larvae's stress resistance rate. The increase in the feedstock cost of the food was observed as the times of Artemia nauplii supply and the co-feeding periods increased. Thus, for intensive larviculture of P. brevis, it is recommended the increasing prey concentration initial of 350 Artemia nauplii larvae-1 day-1 , during 20 days of Artemia nauplii supply, followed by 3 days of co-feeding, before the exclusive formulated diet supply.