Open AccessThe optimum thymol requirement in diets of Channa argus : effects on growth, antioxidant capability, immune response and disease resistance
Author(s) -
Kong YiDi,
Li Min,
Xia ChangGe,
Zhao Jing,
Niu Xiaotian,
Shan XiaoFeng,
Wang GuiQin
Publication year - 2021
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.13217
Subject(s) - thymol , biology , glutathione peroxidase , superoxide dismutase , transaminase , feed conversion ratio , alkaline phosphatase , antioxidant , malondialdehyde , glutathione , catalase , medicine , endocrinology , food science , biochemistry , enzyme , body weight , essential oil
In the present study, we aimed to evaluate the effects of dietary thymol on growth, antioxidant status, liver health, immune response and disease resistance of snakehead fish ( Channa argus ) (initial weight, 11.86 ± 0.15 g). The fish were fed for 56 days with a basal diet supplemented with thymol at 0, 150, 300, 450, 600 and 750 mg/kg, leading to six experimental diets. The final body weight (FBW), weight gain (WG), protein efficiency ratio (PER) and specific growth rate (SGR) were increased as dietary thymol level increased, arriving a summit value at 450 mg/kg dietary thymol level, and then, values of these indices started to decrease when dietary thymol level further rose, and feed conversion ratio (FCR) is the opposite state. Our results showed a significant increase ( p < .05) in the superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH‐Px) activities in liver, spleen, head kidney and intestine with diets supplemented with 300 and 450 mg/kg thymol compared to the control and significantly decrease ( p < .05) in the malondialdehyde (MDA) activity. Results showed that dietary supplementation with 300 and 450 mg/kg thymol significantly increased ( p < .05) the serum acid phosphatase (ACP), alkaline phosphatase (AKP), lysozyme (LZM) activities and immunoglobulin M (IgM), complement 3 (C3), complement 4 (C4) concentrations of C. argus compared to the control, and decreased ( p < .05) the serum glutamic‐pyruvic transaminase (ALT) and glutamic‐oxaloacetic transaminase (AST) activities. Moreover, the expression of HSP70 , TNF‐α , IL‐1β and IL‐8 were down‐regulated in liver, head kidney and intestine by dietary supplementation with 300 and 450 mg/kg thymol, and the expression of IL‐10 and TGF‐β was up‐regulated. After challenge with Aeromonas veronii , survival rates in all thymol treatment groups were significantly increased ( p < .05). Consequently, our results indicate that adequate dietary supplementation thymol can effectively enhance the growth, antioxidant status, immune response and disease resistance of C. argus , and the optimum dietary thymol requirement for maximum WG of C. argus was estimated to be 356 mg/kg.