Sobrevivência e crescimento de larvas de surubim Pseudoplatystoma corruscans (Spix & Agassiz, 1829) sob diferentes condições alimentares

Abstract

The commercial production of the surubim Pseudoplatystoma corruscans is growing more and more at the country, where several they are mainly the aspects related to the creation of that species, that it requests cares ends, in the initial phases, of the which, although it is big the number of individuals produced in an only spawning, the organisms are extremely fragile. The substitution of several plânctons species in the diets of the larvas, for other less costly, in other words, artificial diets are being white of several researches .O success in the cultivation, is directly related the a quality feeding, and in enough amounts to the specific needs of each species. The experiment was accomplished, during the period 08 to 19 February of, 2007, in the Station of Fish farming of Itiúba, belonging to the Company for Development of the San Francisco and of Parnaíba - CODEVASF, in the Municipal district of Porto Real do Colégio, Alagoas-Al. The used larvas were obtained, to leave, induced reproductions of P. corruscans. The objective was of verifying, the effect of different diets, in the survival, growth and earnings of weight of the Pseudoplatystoma corruscans in the first days of life. After the appearance, the larvas were estimated (10.000 in each unit), conditioned in incubators type funnel with capacity of 200 liters, covered with screens type " sombrite ", and flow of water maintained to 8 L/min. After the opening of the mouth, in the first feeding until the end of the experiment, four different diets were offered, with four repetitions, in a frequency of 12 times a day (of two in two hours), in an experiment entirely casual. The diets consisted of different alimentary items: (Diet 1) – 8g of raw egg yolk, of chicken (O); (Diet 2) - 4g of brachoneta, Dendrocephalus brasilliensis, in powdered (B);(Diet 3) -8g of raw egg yolk and 4g of Artemia sp. náuplios (OA); (Diet 4) - 4g of náuplios of Artemia sp (A). models of multiple lineal regression were elaborated, using analysis of united variance (ANOVA) based on the test F of Snedecor and made the tests of comparison of averages, variance analysis (based on the test F), to verify the similarity in the first three days of the larvas, with different diets. In the first day of the experiment the larvas presented medium weight and medium length of 0,34 ± 0,01 mg and 4,1 ± 0,06 mm, respectively. The best result, it was obtained with the treatment raw egg yolk +Artemia nauplios, reaching 4,9 ± 0,31 mg, 15,4 ± 0,52 mm and 81,23 ± 0,52% of survival measured, being 6% superior in relation to diet with Artemia nauplios in the requirement survival not having differentiates signification (p <0,01), and 40% superior in relation to the treatment with the diet powdered branchoneta, having significant difference (p <0,01). The obtained results make possible to end, that in these cultivation conditions, a diet to the base of raw egg yolk, it can be used as food, during the first three days of feeding of larvas of surubim Pseudoplatystoma corruscans, being able to, to be substituted without damages, when related to the growth and survival of the larvas, minimizing like this, the production costs in this phase.