Suplementação de fosfolipídeo e vitamina C na dieta de póslarvas de piracanjuba Brycon orbignyanus (Valenciennes, 1849)

Abstract

This work aimed at evaluating the supplementation of phospholipids and vitamin C, as well as the interaction of these two nutrients, over growth, survival, carcass composition and resistance to thermal stress in post-larvae piracanjuba Brycon orbignyanus. For this, we used 12 tanks, in which were housed 120 postlarvae piracanjuba with initial weight of 0.07g. We used an entirely randomized design arranged in a 2x2 factorial scheme, with four treatments and three replicates. The treatments were comprised of isoenergetics (3582 kcal digestible energy kg-1) and isoproteics (32% protein digestible kg-1) diets, with varying levels of phospholipid (FL) and vitamin C (VC) supplementation. Diet 1 consisted of 0 g kg-1 FL; 0g kg-1 VC, Diet 2, of 0 g kg-1 FL, 2 g kg-1 VC, Diet 3, of 20g-1 Kg FL; 0g kg-1 VC and Diet 4, of 20 g kg-1 FL, 2 g kg-1 VC. The post-larvae were fed four times a day, during period of 34 days. At the beginning and end of the experiment, we determined standard length and weight. In addition, we calculated the performance parameters of feed intake, weight gain, feed conversion, specific growth rate and survival rate. At the end of the experiment, we performed a heat stress resistance test, in which the post-larvae were subjected to low temperature (14 ºC), observing their drive. We also performed chemical analysis of the carcasses of the animals in each treatment. There was no significant difference (P>0.05) between treatments for the variables of standard length, feed intake, feed conversion and survival. For weight gain and specific growth rate, we observed significant interaction (P<0.05), with the best values observed for larvae fed diet 1. For the thermal stress test, the animals that received diet 3 became more resistant. Regarding carcass chemical composition, we observed significantly higher (P<0.05) values of polyunsaturated fatty acids in the animals fed the diet 3. For protein and ether extract, there was a significant effect (P<0.05), appearing higher in fish that did not receive supplementation. There was also significant effect (P<0.05) over calcium content with higher values found in animals that received diet 3, and lower values in the animals fed diet 4. There was no significant difference (P>0.05) for phosphorus content in the carcasses. In conclusion, based on the performance data, body composition and resistance to thermal stress of post-larvae piracanjuba, we recommended diet 3 supplemented with 0.0 g kg-1 of vitamin C (0.350 g kg-1 of vitamin C) and 20.0 g kg-1 of phospholipid.