The main limiting factor in shrimp aquaculture sector is the use of fishmeal (FM) in feed formulation, which account for 50-70% of the production cost . In previous studies in Penaeus vannamei (P. vannamei), relative high FM substitution can be achieved using plant or animal raw ingredients as alternative protein source. T he ingredients choice and % substitution limits the growth performance, generally >50% replacement (animal or vegetal) results in lower growth rates . Therefore, t he present study aims to evaluate the effect of total or high FM substitution by a combination of animal and plant by-products on productive parameters of shrimp under biofloc technology.
Material and Methods : The present study consisted of two experimental phases of shrimp growth. Phase I , d iets with 100% or 92% of by-products inclusion as alternative protein source from animal (A92 and A100), plant (V92 and V100) or a combination of animal and plant origin (AV92 and AV100) were assayed in P. vannamei from 2.5 to 8 g in tanks of 1 m3 (n= 3 replicates/group). Additionally, a control group with a 15% of FM inclusion were also tested to be compared with the experimental diets (Table 1). All diets were isoproteic and isolipidic, with a total 38% and 10%, respectively. In a Phase II , the two experimental groups from Phase 1 that provided the best growth performance were compared with the control from 5 to 14-15 g in tanks of 3.3 m3. All diets in Phase 2 were isoproteic and isolipidic, with a total 34% and 10%, respectively, according to Ferrando-Juan et al. (2022). The growth assays were performed under intensive conditions, with densities of 350 shrimp/ m3 .
Results and discussion :
In Phase I, better growth performance was observed in the experimental diet A92 and AV92, with the lowest values of FCR (Table 2) . Therefore, it was determined that a 92% of FM substitution with alternative animal and plant/animal by-products was possible without compromising growth performance, with no differences with control group. In Phase II, A92 registered a lower growth but without significant differences. In both phases, the results confirm that a high FM substitution is feasible in P. vannamei thanks to a combination of animal and plant by-products as alternative protein source. Previous studies have shown that it is possible to substitute fishmeal with alternative plant protein sources, such as soybean meal, up to 95%, or with animal protein sources, such as poultry by-products, up to 66%. Therefore, the present study provides an alternative and sustainable diet formulation for shrimp production without compromising production. Acknowledgments : The study was funded by the Research Project: “Optimizing shrimp feeding and nutrition in biofloc system (BioFlango)” (PID2020-114574RB-C21). S. Ferrando -Juan contract by MICIN Research Personnel Training Grant (PRE2021-098367). Y. Candela and J. Gómez-Aguilera contract was supported by European Union Next Generation-Plan of Conselleria d’innovació, Universitats, Ciència i Societat Digital of Generalitat Valenciana (INVEST/2022/434).