Uso de artêmias enriquecidas com metionina na nutrição de larvas de pintado amazônico (Pseudoplatystoma reticulatum x Leiarius marmoratus)

Abstract

Larviculture is one of the bottlenecks in fish production, especially when it comes to species of carnivorous food habit, where there are large losses due to cannibalism mortality. However, this phase allows for the largest relative growth in production. Larval nutrition emerges as an alternative through the enrichment of brine shrimp supplemented with the amino acid methionine. Therefore, the objective of this work is to evaluate the use of methionine-enriched brine shrimp in the food of the Pintado Amazônica. We used 576 larvae with initial weight of 0.00072g and 6.02 cm in length. The larvae received the enriched brine shrimp at methionine levels 0, 11, 22 and 33 mg and in each treatment 1.22 g / l of fish oil was added. Four treatments with different levels of methionine with three replications were tested in a randomized block design, totaling 12 plots. The experiment lasted 12 days. For data collection, five biometrics were performed on days 0, 3, 6, 9 and 12 of experiment for analysis of zootechnical parameters and four data collection of alkalinity, total and toxic ammonia and pH. An economic analysis was also performed in order to obtain the most cost-effective treatment through two financial-productive indices, one considering biomass in relation to the total cost (EA 1) , the other evaluating survival in relation to the total cost (EA 2). Statistical analysis was performed by analysis of variance (ANOVA) and means compared by Tukey test (5%). There was no significant difference (<0.05) between treatments regarding water quality and survival parameters. The zootechnical parameters (weight and length) were also not affected (<0.05) by the treatments, except T2 (11 mg Met) which obtained inferior results to the others. As for economic analysis, the most cost-effective treatment considering EA (1) was T1 (0 mg Met). However, according to the EA (2), the best performing treatment was T2 (11 mg Met). These results allow us to conclude that: 1) the use of methionine-enriched brine shrimp at different levels did not improve zootechnical parameters; 2) Regarding survival, 11 mg methionine treatment presented higher numerical values than the others; 3) treatment with 11 mg of methionine (T2) obtained better result obtained in EA 2 which indicates that for each real spent 3.90 percentage units are added to the survival rate.