Abstract In recent years, the coculture of organisms from different trophic levels has been practiced to improve water quality and nutrient consumption. In this context, this study evaluated the effect of Crassostrea stocking density on zootechnical performance and water quality of Litopenaeus vannamei reared in a multitrophic biofloc system during the nursery phase. The experimental design was completely randomized with four treatments: control (shrimp monoculture) and three treatments with oysters (3.21 ± 1.26 cm) at densities of 100, 200 and 300 oyster m−2, for 45 days. Water quality, zootechnical performance parameters of shrimp and oysters, proximate composition of microbial flocs, Vibrio count from water, shrimp and oysters samples and total hemocyte counts from shrimp and oyster samples were evaluated. For water quality, multitrophic biofloc system treatments had the lowest amounts of settleable solids, resulting in lower settling chamber use than the control. However, a high density of oysters (300 oysters m−2) increased total ammonia nitrogen and nitrite-N levels, which had maximum values of 4.01 and 4.63 mg L−1, respectively. The final average weight and cumulative growth of oysters were 16.23 ± 3.45 g and 18.91 ± 5.24%, respectively, corresponding to an average growth of 4.07 ± 0.34 mm month−1. In shrimp performance, the higher density treatment (300 oysters m−2) had the lowest values of final weight and yield (0.94 ± 0.03 g and 2.26 ± 0.05 Kg m−3) and the lowest nutritional quality of the microbial floc (14.96% protein and 3.71% lipid). The Vibrio count was significantly lower in all the multitrophic biofloc system treatments compared to the control, with an average reduction of 37.32% in water and 75.69% in shrimp hepatopancreas. Stocking densities of up to 200 oysters m−2 did not affect shrimp growth in the multitrophic biofloc systems evaluated. The multitrophic biofloc system used in this research is a viable option for controlling nitrogen compounds and solids and reducing Vibrio in a shrimp biofloc system during the nursery phase.

中文翻译：

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牡蛎养殖密度的影响。南美白对虾苗圃中的多营养生物絮团系统

摘要 近年来，不同营养级生物的共养已被用于改善水质和养分消耗。在此背景下，本研究评估了养殖密度对南美白对虾在多营养生物絮团系统中育苗阶段饲养性能和水质的影响。实验设计完全随机，有四种处理：对照（​​虾单养）和三种牡蛎（3.21 ± 1.26 cm）处理，密度为 100、200 和 300 牡蛎 m-2，持续 45 天。对水质、虾和牡蛎的畜牧学性能参数、微生物絮体的近似组成、水、虾和牡蛎样品中的弧菌计数以及虾和牡蛎样品中的总血细胞计数进行了评估。对于水质，多营养生物絮团系统处理的可沉降固体量最低，导致沉降室使用量低于对照。然而，高密度的牡蛎（300 只牡蛎 m-2）增加了总氨氮和亚硝酸盐-N 水平，最大值分别为 4.01 和 4.63 mg L-1。牡蛎的最终平均重量和累积生长分别为 16.23 ± 3.45 g 和 18.91 ± 5.24%，对应于 4.07 ± 0.34 mm 月-1 的平均生长。在对虾性能方面，较高密度处理（300 只牡蛎 m-2）的最终重量和产量最低（0.94 ± 0.03 g 和 2.26 ± 0.05 Kg m-3），微生物絮团的营养质量最低（14.96%蛋白质和 3.71% 脂质）。与对照相比，所有多营养生物絮团系统处理中的弧菌计数显着降低，水平均减少37.32%，虾肝胰腺平均减少75.69%。在评估的多营养生物絮团系统中，高达 200 只牡蛎 m-2 的放养密度不会影响虾的生长。本研究中使用的多营养生物絮团系统是在育苗阶段控制氮化合物和固体以及减少虾生物絮团系统中弧菌的可行选择。