Extrato de levedura e microalga como suplemento em rações restritas em farinha e óleo de peixe: Efeito no desempenho zootécnico de juvenis do Penaeus vannamei

Abstract

This study evaluated the growth performance of juveniles of Penaeus vannamei fed diets restrained in fish meal (FM) and fish oil (FO) supplemented with a commercial yeast extract (YE) and microalgae extract (ME). Ten isonitrogenous and isolipidic diets were prepared containing decreasing levels of FM and FO, different dietary inclusion levels of YE and ME, and different protein replacement strategies defined as plant protein diets and animal protein diets. The Control and Positive Control (CP) diets were formulated with 15.00% FP (% of the diet, as-is), but the second was supplemented with 0.25% YE. The V50M, V50C, A50C and A50C+ diets were formulated with 7.50% FM (50% restriction) and supplemented with 0.43, 0.43, 0.43 and 0.64% ME and zero, 1.00, 1.00 and 1.50% of the YE, respectively. The V75M, V75C, A75C and A75C+ diets were formulated with 3.75% FM (75% restriction) and supplementation of 0.51, 0.51, 0.64 and 0.65% of ME and zero, 1.50, 1.50, and 2.00% YE. A total of 2,480 shrimp of 0.59 ± 0.06 g were stocked in 80 outdoor tanks of 1 m3

under 61 animals/m2. Shrimp were fed four times a day for 62 days. At harvest, the final body weight (BWF), survival (FS), final yield (FY), apparent feed intake (AFI) and feed conversion ratio (FCR) reached 11.65 ± 1.95 g, 87.7 ± 8.1%, 583 ± 64 g/m2, 895 ± 62 g/tank and 1.52 ± 0.17, respectively. FS, FY, CAR and FCR were not affected by diet type. However, the BWF was significantly influenced. Animals fed diets A75C (3.75% FM; 0.64% ME: 1.50% YE), A75C+ (3.75% FM; 0.64% ME; 2.00% YE) and V75M (7.50% FM; 0.43% EM; 1.50% YE) achieved the highest FBW (12.30 ± 1.88, 12.16 ± 1.90 and 11.96 ± 1.87 g, respectively). At the 75% replacement level, animal protein-based diets were more effective compared to plant-based protein diets. With regardsto the YE, in diets with 15% FM, a 0.25% supplementation increased the BWF, while in plant-based, 1.00% YE with 7.50% FM had no influence, and; at 1.50% YE with 3.75% had a negative effect on BWF. A combined supplementation with 0.50% YE with 0.21 or 0.14% ME in animal-based diets with 7.50 and 3.75% FM, respectively, had not influence on shrimp growth performance. The A75C diet showed the lowest production cost (3,84 ± 0,33 USD/kg of shrimp) and the V75M the highest (8,60 ± 6,14 USD/kg of shrimp). Adding EL to the feed reduced the production cost (even if in a discreet way). Research has shown that the dietary supplementation of YE and EL has positive benefits to shrimp BWF. However, future investigations are necessary to define the optimal dietary inclusion for each product.