Sonophoresis efficiency: consequences of methyl donors supplementation at early developmental stage in gilthead seabream (Sparus aurata). Effects on growth, nutrient metabolism, egg and larval quality, and methylation patterns of larvae and juvenile fish

Abstract

Dissertação de mestrado, Aquacultura e Pescas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016It is essential that the vegetable ingredients that will be use in Aquaculture feeds can maintain the growth parameters in fish when compared with the fish meal diets. Studies have shown that the replacement may be achieved until a certain level without affecting the growth parameters. Sometimes the vegetable diets lack essential amino acids that need to be supplemented in the feeds, one of the amino acids that sometimes is lacking is the Methionine. In this study the gilthead seabream (Sparus aurata, L. 1758) eggs were supplemented with Methionine to understand if the supplementation had an effect in the larvae growth. The supplementation was performing using the innovative technique Sonophoresis. The amount of Methionine that entered the supplemented eggs was 33.1- fold higher than in the eggs that were not supplemented. Due to the supplementation the oil globule area of the larvae of the treatment MET was higher in the 2 and 4 days after hatching (DAH), also the dry weight was higher in the larvae of treatment MET during the first week. After the first week the larvae of both treatments presented similar growth parameters so a later supplementation was planned and performed at 57 DAH. This second supplementation was done using a Vegetable feed (VEG) supplemented with methionine. At the end of the experiment the juveniles that were from the eggs supplemented and were fed with VEG diet (METVEG) presented higher condition factor (K). In conclusion the Sonophoresis technique was a success, which allowed the alteration of the composition of the egg with the methionine, the early supplementation was able to promote growth in gilthead seabream larvae. The VEG diet did not negatively affected the survival and promoted fish to achieve similar weight to the FM diet