Effect of different water biofloc contents on the growth and immune response of gibel carp cultured in zero water exchange and no feed addition system

Abstract

This study evaluated the growth and immune response of gibel carp (Carassius auratus gibelio) cultured under no feed addition biofloc technology (BFT) system at different total suspended solid (TSS) concentrations (10, 300, 600, 800 and 1,000 mg/L for group BF0‐NF, BF300‐NF, BF600‐NF, BF800‐NF and BF1000‐NF) for 30 days. The results demonstrated that bioflocs contained rich nutrients, and gibel carp eaten bioflocs showed higher weight gain, specific growth and survival. Digestive enzyme activities such as pepsin and amylase increased significantly in BF300/600/800/1000‐NF groups than those in BF0‐NF group. Antioxidant response including superoxide dismutase and total antioxidant capacity in serum and skin mucus was also enhanced significantly (p < .05). In addition, six immune‐related genes were examined by RT‐qPCR. Compared with BF0‐NF group, expression levels of immune genes intelectin (ITLN), dual specificity phosphatase 1 (DUSP 1), keratin 8 (KRT 8), myeloid‐specific‐peroxidase (MPO), c‐type lysozyme (c‐lys) and interleukin‐11 (IL‐11) were up‐regulated by 78.1‐, 23.9‐, 13.8‐, 138.8‐, 401.8‐ and 91.1‐fold, respectively. The highest expression values were observed at TSS of 600–800 mg/L. This study suggested that bioflocs can be uptaken by gibel carp as a food source, and have a potential to be used as a supplemental food for aquaculture.

Evaluation of hemato-immunological parameters and stress indicators of common carp (Cyprinus carpio) in different C/N ratio of biofloc system

“…Heterotrophic bacteria in BFT act as probiotics and immunostimulants to activate the non-specific immune system (Lee et al 2017). The effects of heterotrophic bacteria as immunostimulants have already been studied in several freshwater fish such as common carp (Bakhshi et al 2018), Litopenaeus vannamei (Lee et al 2018), Gibel carp (Zhang et al 2018), and African catfish (Romano et al 2018). These results are in agreement with previous studies in which the BFT showed beneficial effects on the immune system of fish (Najdegerami et al 2018).…”

“…The slow decline in levels of DO was probably caused by higher biological demand associated with total water biomass increment and the cumulating of biological materials and temperature range. On the other hand, nitrification causes production of NO2 and NO3; in the BFT, the incomplete denitrification of NO3 might produce NO2, and dissimilatory NO3 reduction to ammonia (TAN) might also happen in the trial situation (Zhang et al 2018). Aerobic bacteria which possess denitrifying capacity significantly reduce nitrite via oxygen demand denitrification (Vinatea et al 2018;Kim et al 2014).…”

“…In biofloc systems, communities of active heterotrophic microorganisms can be fostered by increasing the C/N ratio of culture water and assimilating the waste nitrogen resulting in the production of new microbial biomass, protozoans, and some useable metazoans (Avnimelech 2007;Ray 2012;Devi and Kurup. 2015;Zhang et al 2018). As a supplemental food source is available for cultured species, the biofloc can be used as a remarkable part of protein demand (Vinatea et al 2018;Crab et al 2012;Xu and Pan 2012).…”

“…As a supplemental food source is available for cultured species, the biofloc can be used as a remarkable part of protein demand (Vinatea et al 2018;Crab et al 2012;Xu and Pan 2012). Recently, the biofloc technology (BFT) applied in aquaculture has received considerable attention, mostly because of feed protein recycling, high production yields, water quality, and pathogenic infection control (Vinatea et al 2018;Xu and Pan 2012;Zhang et al 2018). Annual production of common carp was over 4.4 million metric tonnes in 2017 and its production has progressively increased in the last decades (FAO 2019).…”

The nitrification process for nitrogen removal in biofloc system aquaculture

“…In the best‐case scenario, these systems offer the possibility of working under zero water exchanges (Monroy‐Dosta et al 2013). Also, working with BFT systems has allowed producers to increase their crop densities (de Lorenzo et al 2016; Xu et al 2016), doubling and tripling the production per unit area without sacrificing the individual size of fish or shrimp (Zhang et al 2018a), improving the immune system (Chen et al 2018) and the overall health status of the culture system by the action of probiotics contained in the biofloc mass (Ali et al 2016; Tepaamorndech et al 2018).…”