1. Dietary lysine levels modulate the lipid metabolism, mitochondrial biogenesis and immune response of grass carp, Ctenopharyngodon idellus.
- Author
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Xie, Shiwei, He, Juyun, Masagounder, Karthik, Liu, Yongjian, Tian, Lixia, Tan, Beiping, and Niu, Jin
- Subjects
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LIPID metabolism , *CTENOPHARYNGODON idella , *LYSINE , *OXIDANT status , *IMMUNE response , *LIPOLYSIS , *GLUTATHIONE peroxidase - Abstract
A 10-week experiment was conducted to evaluate the effects of dietary lysine levels on growth performance, lipid metabolism, anti-oxidant capacity, mitochondrial biogenesis and immune response of grass carp, Ctenopharyngodon idella. Fish (mean initial weight 51.01 ± 0.17 g) were fed seven diets containing graded levels of lysine (1.69 %, 1.79 %, 1.91 %, 2.01 %, 2.11 %, 2.24 % and 2.31 %). Results showed that fish fed the control diet (1.69 %) showed lower weight gain (WG) and higher feed conversion rate FCR than those fed 2.01–2.31 % lysine (P < 0.05). Viscerosomatic index decreased when dietary lysine increasing from 1.69 % to 2.11 % (P < 0.05). Suitable dietary lysine levels enhanced the lipolysis and mitochondrial biogenesis of grass carp. Total antioxidant capacity (T-AOC) in the liver was higher in fish fed 2.24 % dietary lysine than those fed diets containing 1.69 % and 1.79 % lysine (P < 0.05). The malonaldehyde (MDA) contents in liver decreased when dietary lysine increased from 1.69 % to 2.01 % (P < 0.05). Relative mRNA levels of glutathione peroxidase and catalase in liver and intestine were affected by dietary lysine levels (P < 0.05). B-cell lymphoma 2 (Bcl-2) mRNA level in liver was up-regulated and inhibitor kappa B kinase β (IKKβ) mRNA level in the intestine was down-regulated by increasing dietary lysine levels (P < 0.05). Second-order regression based on WG indicated the suitable level of lysine in feed of grass carp was 2.24 % (6.19 % protein). • Dietary deficiency of lysine would impair the growth performance and feed utilization of grass carp. • The protein synthesis, lipolysis and mitochondrial biogenesis of grass carp might be enhanced by lysine. • Immune response and anti-oxidant defense system of grass carp might be affected by dietary fish lysine levels. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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