EFFECT OF THE REPLACEMENT OF ARTEMIA SP. FOR THE NEMATODE PANAGRELLUS REDIVIVUS ON THE LARVAL GROWTH AND SURVIVAL OF THE FRESHWATER PRAWN (MACROBRACHIUM ROSENBERGIL

Abstract

Aiming at identifying the effect of the replacement of the nauplii of Artemia sp for the nematode Panagrellus redivivus on the larval growth and survival of the freshwater prawn Macrobrachium rosenbergii, an experiment was developed in which the following treatments were tested: 100% Artemia (3 NAS/mL)(T1); 66% Artemia (2 NAS/mL) + 34% Panagrellus redivivus (23 NEM/mL)(T2); 34% Artemia (1 NAS/mL) + 66% Panagrellus redivivus (46 NEN/mL) (T3); 100% Panagrellus redivivus (70 NEM/mL) (T4). The outcomes of the final survival in post-Iarvae were analyzed through the X² test and demonstrated a statistical superiority of T1 treatment (46.72%) over T2 and T3 treatments: 31.20% and 8.10%, respectively. The T4 treatment (100% Panagrellus) presented total mortality on the 6th day of the experiment. The average dry weight of the post-Iarvae was analyzed statistically by ANOVA and Duncan (P > 0.05) and presented no meaningful differences in values: 1.87 mg (T1), 1.74 mg (T2) and 1.54 mg (T3). The first metamorphosis of post-Iarvae occurred on the 21st day in T1 treatment, on the 23rd in T2 and on the 29th in T3. Consequently, the cycle of hatchery until the metamorphosis of 95% of post-Iarvae (PL1), in average in lasts 34 days in T2 and 39 days in T3, whereas 29 days in T1 treatment. The death rate between the 11th and the 20th day of hatchery based on the number of dead larval stored in the daily material siphoned presented no meaningful statistical difference between the T2 treatment (9.3%) and the T1 witness (8.5%). After the 21th day, the results showed no meaningful statistical difference between the death rate in the T2 treatment (2.9%), T3 (3.0%) and T1 witness (2.3%). The results evidentiate a tendency of diminution from the death after the 5th larval stage in the treatments that utilized the Panagrellus nematode as replacement of the Artemia sp. at a rate of 34% (T2) and 66% (T3), suggesting the possibility replacement of the Artemia sp. for the Panagrellus nematode after the V larval stage for a 34% of replacement and after the VIII stage for a 66% of replacement.