摘要
This dissertation was primarily focused on the immune response,inflammatory response and molecular mechanisms in the skin,head kidney and spleen of grown-up grass carp(Ctenopharyngodon idella).Six iso-nitrogen diets differing in lysine concentrations(5.6,8.5,11.6,14.4,17.5 and 20.7 g/kg)were fed to 540 grass carp(164.85±0.79 g)for 60 d.After that,grass carp were challenged by Aeromonas hydrophila for 6 d.This study revealed that lysine deficiency(1)suppressed the growth performa,nce of the fish and decreased their ability to resist skin lesion morbidity,(2)impaired the immune organ s immune response by decreasing the gene expressions of mucin,liver-expressed antimicrobial peptide(LEAP)-2B,β-defensin-1 and LEAP-2A and the production of antibacterial compounds of grown-up grass carp,and(3)aggravated the inflammatory response of immune organs in the fish by increasing the gene expressions of pro-inflammatory cytokines(interferon y2[IFN-γ2],tumor necrosis factorα[TNF-α],interleukin[IL]-15,IL-17D,IL-12p40,IL-6 and IL-8)and down-regulating anti-inflammatory cytokines(IL-11,transforming growth factorβ1[TGF-β1],IL-10 and IL-4/13A),which were tightly correlated with signal transducer and activator of transcription(STAT)1 and STAT3 signaling pathway,respectively.The different phenomenon in the skin,spleen and head kidney of fish may be correlated with the difference in gene subtype.In addition,using quadratic regression analysis of percent weight gain(PWG),skin lesion morbidity,and the lysozyme activities in the spleen and head kidney,the dietary lysine requirements for grown-up grass carp were estimated to be 13.58,13.51,14.56 and 14.18 g/kg,respectively.
基金
National Key R&D Program of China(2019YFD0900200,2018YFD0900400)
National Natural Science Foundation of China for Outstanding Youth Science Foundation(31922086)
the Young Top-Notch Talent Support Program of National Ten-Thousand Talents Program,the Earmarked Fund for China Agricultural Research System(CARS-45)
Outstanding Talents and Innovative Team of Agricultural Scientific Research(Ministry of Agriculture)
Foundation of Sichuan Youth Science and Technology Innovation Research Team(2017TD0002)
Key Research and Development Plan in Sichuan Province(2018NZ0007)
Supported by Sichuan Science and Technology Program(2019YFN0036).