Captura, adaptação, reprodução e perfil de aminoácidos e ácidos graxos de ovos e larvas de pacamã (Lophiosilurus alexandri)

Abstract

This study aimed to analyse the capture, transport, adaptation and reproduction of Lophiosilurus alexandri wild breeders when moved to laboratory conditions. Two sampling sessions in natural habitats were carried out. The surviving animals from the first and second sampling sessions were placed into four 5 m3 tanks. A layer of sand was added to two tanks and they were kept at a temperature of 28ºC. Spawning occurred naturally 30 days after temperature rise, but only in tanks with a sand bottom. In the first reproductive period, 24 spawnings were collected from these tanks. In the second reproductive period, the animals were sexed by cannulation and divided again into four tanks with sand on the bottom and kept at a temperature of 28ºC. Spawning occurred in all tanks, totalling 36. During reproduction, samples of eggs, newly hatched larvae (NHL), and larvae at the end of lecithotrophic period(eight days after hatching) (LPL) were collected to determine the amino acid and fatty acid profiles. Crude protein did not change throughout the experiment (P > 0.05) and concentration of lipids was highest in NHL (P < 0.05). Glutamine was the amino acid (AA) found in the highest concentrations in eggs, NHL, and LPL. The essential amino acids (EAA) isoleucine, leucine, and valine decreased in LPL, while in eggs and NHL, the values were higher and similar to each other. Arginine and lysine showed lower and similar amounts in eggs and NHL and increased in LPL. The dispensable amino acids (DAA), such as aspartic acid,tyrosine, and glycine increased in LPL while alanine decreased in this stage of life. The neutral lipids (NL) percentage increased in LPL larvae. The SFA (saturated fatty acids) decreased during ontogeny, while MUFA (monounsaturated fatty acids) decreased only in LPL. The PUFA (polyunsaturated fatty acids) was highest in LPL, probably due to increased percentages of the fatty acids Arachidonic (20:4n-6) (ARA), Eicosapentaenoic (C20:5n3) (EPA), and Docosahexaenoic (C22:6 n3) (DHA). Polar fatty acids (PL) were found in larger percentages in eggs and NHL and decreased in LPL. The SFA decreased during ontogeneticdevelopment, while MUFA decreased only in LPL. The PUFA was highest in LPL, probably due to the increased percentage of ARA and DHA. The percentage of EPA remained unchanged throughout the experiment. The pacamã is able to adapt and reproduce inlaboratory conditions, and it is possible to manipulate its reproductive period by controlling the water temperature and food. Protein is kept during ontogenetic development although there were changes in the amino acid classes, such as a decrease (IAA) of isoleucine, leucine,and valine in LPL. L. alexandri preferably use SAFAs and MUFAs as an energy source, from both the NL and PL fractions, during its early development.