Open AccessInfluence of differential protein levels of feed on growth, copper‐induced immune response and oxidative stress of Rhynchocypris lagowski in a biofloc‐based system
Author(s) -
Yu Zhe,
Huang ZhangQi,
Du HongLin,
Li HongJin,
Wu LiFang
Publication year - 2020
Publication title -
aquaculture nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.941
H-Index - 79
eISSN - 1365-2095
pISSN - 1353-5773
DOI - 10.1111/anu.13158
Subject(s) - superoxide dismutase , biology , antioxidant , malondialdehyde , catalase , amylase , lysozyme , glutathione peroxidase , oxidative stress , alkaline phosphatase , immune system , food science , ascorbic acid , biochemistry , enzyme , immunology
This study compared the influences of differential protein levels of feed on growth, copper‐induced digestive enzyme activity, immune response, oxidative stress and Nrf2 signalling molecules genes expression of Rhynchocypris lagowski in a biofloc‐based system and traditional autotrophic system. Four hundred and fifty R. lagowski were fed four experimental dietary containing graded levels of protein from 25% to 37% (referred as biofloc technology [BFT]25, BFT29, BFT33 and BFT37, respectively) in a biofloc‐based system, and 37% crude protein level (control group) were cultured in an autotrophic system in 8 weeks. At the end of the trial, there was an improvement of 50.35%–61.64% in terms of growth performance (weight gain rate); 0.25–0.53 (U/mg prot) amylase; 6.9–8.02 (U/ml) lysozyme (LZM); and 7.98–8.12 (U/ml) total superoxide dismutase (T‐SOD) in R. lagowski cultured in BFT37 groups as compared to control. Obviously, the growth performance, digestive enzymes activity, immune response, antioxidant statue and antioxidant‐related genes expression of R. lagowski fed with the same protein level in BFT system were significantly higher than those in the control group ( p < .05). Furthermore, the level of T‐SOD in liver and kidney and interferon‐γ in liver of BFT33 group were also significantly higher than that of control group ( p < .05). Moreover, there was no notable difference of LZM, alkaline phosphatase, complement C3, C4, heat shock proteins 70, heat shock proteins 90, insulin‐like growth factor I, glutathione peroxidase, catalase, total antioxidant capacity, malondialdehyde, Ascorbic acid in gill, liver, kidney, gut and serum among the BFT29 groups and those in the control ( p > .05). Besides, bioflocs assists in regulating the expression of Nrf2 signalling molecules including Nrf2 , Keap1 , Maf , HO‐1 , CAT , CuZn‐SOD , GPX and GCLC . We summarized that despite the low protein content in feed, BFT system has the potential to promote growth performance, alleviate copper‐induced immunosuppression and oxidative stress of juvenile R. lagowski .