Today, the use of food additives is increasing in aquaculture due to their role in improving growth, nutrition, reproduction, immune system and resistance against diseases and environmental stressors (Dabrowski and Ciereszko, 2001; Güroy et al., 2012; Mohapatra et al., 2013a, 2013b; Dawood et al., 2018; Pereira da Costa and Campos Miranda-Filho, 2020; Khanjani and Sharifinia, 2021). The movement of aquaculture towards intensive production has increased the risk of crowding stress (Yin et al., 1995; Caipang et al., 2009; Lin et al., 2014; Lin et al., 2018a, 2018b). Many studies have shown that crowding stress seriously reduces the immune system of fish, which may increase the risk of various diseases (Ortuno et al., 2001; Lin et al., 2018a, 2018b; Paray et al., 2020a, 2020b; Adineh et al., 2021a, 2021b, 2021c). In addition, in intensive fish sys tems, if water quality management is not done efficiently, the increased concentrations of toxic substances such as ammonia may cause fish mortality (Randall and Tsui, 2002; Hargreaves and Tucker, 2004; Datta, 2012). Like other vertebrates, corticosteroids, especially cortisol, play an important role in modulating stress in fish (Pankhurst, 2011; Norris and Hobbs, 2020). During the period of stress, high energetic costs are imposed on the fish, which reduces the growth and immune system of the fish (Tort, 2011; Sadoul and Vijayan, 2016; Schreck and Tort, 2016). The immunosuppressive effects of cortisol have been demonstrated by in vitro and in vivo studies (Espelid et al., 1996; Esteban et al., 2004; Cortés et al., 2013). During the last decade, a wide range of natural and syn thetic immune stimulants (IMS) have been used in aquaculture (Mehana et al., 2015). Herbal supplements and probiotics have been shown to improve effectively the immune system of fish (Banerjee and Ray, 2017; Alagawany et al., 2020; Elumalai et al., 2020a, 2020b). The chemical composition of medicinal herbs includes some compounds with anti-stress and immunogenic properties such as flavonoids, phenolic compounds, carotenoids and terpenes (Shakya, 2016; Tungmunnithum et al., 2018). Probiotics, were defined as “live microbial feed supple ments” which beneficially affect the host animal by improving its in testinal microbial balance (Kirihara et al., 2018). Lactobacillus, Bacillus, Lactococcus, Clostridium, Leuconostoc, Entero coccus, Shewanella, Carnobacterium, and Aeromonas are among most common probiotics used in aquaculture (Takanashi et al., 2014). Pro biotics generally improve the fish immune system mainly through modulating the intestinal microflora, competing with and removing pathogens in the gut, and stimulating the innate immune system (Gatesoupe, 1999; Gómez and Balcázar, 2008; Denev et al., 2009; Nayak, 2010; Aguirre-Guzman et al., 2012). Although the mitigating role of IMS against crowding stress has been studied in fish, (Montero et al., 1999; Reyes-Cerpa et al., 2018a, 2018b; Yousefi et al., 2019a, 2019b; Adineh et al., 2021), studies to find and introduce more effective IMS are always welcome. RE is a plant-derived polyphenolic compound with antioxidant and anti-inflammatory propertises (A Santos et al., 2013; Wilson et al., 2015a, 2015b; Colica et al., 2018; Banez et al., 2020). Some studies have also reported the immunogenic effects of resveratrol in fish (Kowalska et al., 2017; Yan et al., 2017; Jia et al., 2019a,2019b,2019c, 2019d; Tan et al., 2019a, 2019b; Giordo et al., 2020; Naderi Farsani et al., 2021). Specific lactic acid bacterial strains, such as LAB, have been considered as probiotics, because of their health benefits (Quinto et al., 2014). LAB is categorized as a probiotic strain because of its beneficial effects in human health and prevention of disease transmission (Hosseini et al., 2016a, 2016b). In the present study, we are trying to investigate the potentials of a plant derived compound, resveratrol (RE) and the pro biotic, Lactobacillus acidophilus (LAB) and their combination to improve growth and immunity of the common carp, Cyprinus carpio under intensive fish culture. The results of the present study may help us to carp aquaculture enhancing
Aquaculture Reports
