Alimentação durante a fase inicial da larvicultura de Zebrafish (Daniorerio)

Abstract

The larval stage is considered the most critical phase in fish cultivation due to high vulnerability of individuals to various cultivation parameters. Providing an inadequate diet and nutritional requirements results in decreased fish growth and survival. Danio rerio is a species of fish with several characteristics that make it a model organism in scientific research. However, little information exists in the literature about an adequate food protocol for these fish larvae. The objective was to determine a feeding protocol using live food and formulated food for zebrafish larvae. The experiment was conducted at UFLA Central Biottery and lasted 32 days. 900 zebrafish larvae obtained from Central Biottery breeders were used. On the 8th day after fertilization (dpf), the supply of the proposed diets began. The experimental design was completely randomized, using live feed (Artemia sp (A).) And formulated feed (freeze-dried brine shrimp (AL), spirulina feed (RSp), chlorella feed (RCh) and commercial feed (RC). The density used was 45 larvae/L, totaling 5 treatments and 4 repetitions. The larvae were fed 6 times a day (8h; 10h; 12h; 14h; 16h; 18h). For measurement of morphometric parameters, the larvae were weighed on days 0, 12, 22 and 32 days after the beginning of the experiment in which the average weight of the larvae was calculated. They were also photographed in optic microscope (objective 4X) for growth rate and then evaluated using the Motic Image Plus® program. Histological analyzes were performed on days 12, 22 and 32 after the beginning of the experiment, to evaluate the growth of skeletal muscles (hypertrophy and hyperplasia). The highest survival values were obtained with AL feeding and treatment A obtained the minimum survival values. The RC diet presented significantly greater total length and eye diameter (p <0.05) than the other diets up to 22 days. Significantly lower results (p <0.05) were presented by the RSp diet in all analyzed growth variables. Analyzing mouth opening at 12 days, the treatment containing AL was significantly higher (p <0.05) followed by treatment A, and at 22 days, the AL diet showed significant differences (p <0.05) compared to the RCh diet. This work showed that in the early stages of zebrafish development, diets of lyophilized brine shrimp should be used as food and the diet may be supplemented with other foods to obtain better results.