Aquaculture Research. 2021;00:1–6. wileyonlinelibrary.com/journal/are | 1 © 2021 John Wiley & Sons Ltd Received: 16 September 2020 | Revised: 8 February 2021 | Accepted: 17 February 2021 DOI: 10.1111/are.15198 SHORT COMMUNICATION The effects of high concentration of carbon dioxide on performance and tissue histology of shrimp Litopenaeus vannamei Ramón Casillas-Hernández 1,2 | Karla Janeth Arévalo-Sainz 2 | Jose Reyes Gonzalez-Galaviz 3 | María del Carmen Rodríguez-Jaramillo 4 | Rafael Apolinar Bórquez-López 1 | Juan Carlos Gil-Núñez 1 | María Belem Flores-Pérez 2 | Fernando Lares-Villa 1,2 | Jose Cuauhtémoc Ibarra-Gámez 1,2 | Ramón M. Molina Barrios 1 1 Departamento de Ciencias Agronómicas y Veterinaria, Instituto Tecnológico de Sonora, Ciudad Obregón, México 2 Programa de Doctorado en Biotecnología, Instituto Tecnológico de Sonora, Ciudad Obregón, México 3 CONACYT-Instituto Tecnológico de Sonora, Ciudad Obregón, México 4 Centro de Investigaciones Biológicas del Noroeste, Calle Instituto Politécnico Nacional # 195, La Paz, Mexico Correspondence: Ramón Casillas-Hernández, Departamento de Ciencias Agronómicas y Veterinaria, Instituto Tecnológico de Sonora, 5 de Febrero 818 Sur, Colonia Centro, 85000 Ciudad Obregón, Sonora, México. Email: ramon.casillas@itson.edu.mx Funding information PROFAPI ITSON, Grant/Award Number: 2020-0005, 2020-0093 and 2020-0483; Consejo Nacional de Ciencia y Tecnología, Grant/Award Number: Catedras CONACYT project No. 1037 Keywords: dissolved carbon dioxide, histopathology, hyperintensive system, Litopenaeus vannamei, performance In aquaculture, dissolved carbon dioxide (CO 2 ) is generated from the metabolism of cultured organisms and bacterial populations (Skov, 2019) and its increase is mainly due to culture intensification and inefficient water treatment (Ebeling & Timmons, 2010; Good et al., 2010). Research on safe CO 2 levels in aquaculture systems has been studied mainly in fish (Skov, 2019). The toxicity caused by high CO 2 concentrations, combined with other water quality parameters such as oxygen saturation and alkalinity, leads to histopathological alter- ations, changes in energy metabolism and in the immune system of salmon, trout and other fish of the family Cyprinidae, affecting health and growth (Fivelstad et al., 2013; Hosfeld et al., 2008; Good et al., 2018; Jesus et al., 2017). In Salmo salar L. indicate that 33 mg/L of CO 2 can generate significant changes in the concentration of plasma chloride in the blood and affect the health and growth (Fivelstad et al., 2015; Good et al., 2018). In Seriola lalandi, an increment from 3.28 to 39.6 mg/L in CO 2 concentration, the metabolic indicators were significantly affected (Pan et al., 2020). In Artemia sinica, the acidification of water by CO 2 affects physiological processes and protein expression (Chang et al., 2016). In Litopenaeus vannamei, the increase in CO 2 causes stress and affects CO 2 excretion in the bran- chial epithelium and the haemolymph´s pH, likewise the maximum non-lethal concentration and acute toxicity of the CO 2 are 23.8 and 59.12 mg/L, respectively (Furtado et al., 2014, 2017). Therefore, the effect generated by a high CO 2 concentration (39.20 ± 1.76 mg/L) during a 70-day bioassay and its relationship with the productive performance and the histopathological alterations of L. vannamei was evaluated. The present work was carried out at Instituto Tecnologico de Sonora, Mexico, with L. vannamei small juveniles. The animals' use was conducted with ethical standards and approved by the Ethics and Biosafety Committee of the Institution (2020–05). Two RAS were used, each one with six tanks with a capacity of 250 L of seawa- ter. One RAS with six tanks was used to receive the additional CO 2 and achieve dissolved concentrations of 39.20 ± 1.76 mg/L for the high treatment. The remaining six tanks did not receive CO 2 (control treatment), so the levels were 10.36 ± 2.76 mg/L CO 2 (Figure 1). After 40-day acclimatization, the shrimp (0.84 ± 0.27 g) were randomly placed at a density of 100 ind/m 3 . During the 70-day experiment, shrimp were fed daily 12% biomass. For the control and management of the daily food rations, feeding trays were used, with adjustments of weekly food rations according to the to the shrimp growth (Bórquez-López et al.,2017). Shrimp