In recent years,high-fat diet(HFD)has been widely applied in aquaculture,which reduces the intestinal health of cultured fish.The current study evaluated the protective effects of nano-selenium(nano-Se)on intestinal health of juvenile grass carp(Ctenopharyngodon idella)fed with HFD.A total of 135 experi-mental fish were fed with a regular diet(Con),a HFD(HFD)and a HFD containing nano-Se at 0.6 mg/kg(HSe)for 10 weeks.The results showed that dietary nano-Se significantly improved the survival rate and feed efficiency which were reduced by HFD in juvenile grass carp(P＜0.05).Also,nano-Se(0.6 mg/kg)supplement alleviated intestinal damage caused by the HFD,thus maintaining the integrity of the in-testine.Moreover,it significantly up-regulated the expression of genes related to tight junction(ZO-1,claudin-3 and occludin),anti-oxidization(GPx4a andGPx4b),and the protein of ZO-1 in the intestine of juvenile grass carp,which were depressed by the HFD(P＜0.05).Furthermore,nano-Se supplementation significantly suppressed the expressions of genes related to the inflammation,including inflammatory cytokines(IL-8,IL-1β,IFN-y,TNF-α and IL-6),signaling molecules(TLR4,p38 MAPK and NF-κB p65),and protein expression of NF-κB p65 and TNF-α in the intestine of juvenile grass carp which were induced by the HFD(P＜0.05).Besides,dietary nano-Se normalized the intestinal microbiota imbalance of juvenile grass carp caused by the HFD through increasing the abundance of the beneficial bacteria,e.g.,Fuso-bacteria.Finally,dietary nano-Se increased the production of short chain fatty acids(SCFA)in the in-testine,especially for butyric acid and caproic acid,which were negatively related to the increase of intestinal permeability and inflammation.In summary,supply of nano-Se(0.6 mg/kg)in HFD could effectively alleviate intestinal injury of juvenile grass carp by improving intestinal barrier function and reducing intestinal inflammation and oxidative stress.These positive effects may be due to the regulation of nano-Se on intestinal microbiota and the subsequently increased beneficial SCFA levels.

Sha Liu;Haibo Yu;Pengju Li;Chi Wang;Guohao Liu;Xiaotian Zhang;Cheng Zhang;Meng Qi;Hong Ji

College of Animal Science and Technology,Northwest A&F University,Yangling,712100,China;Key Laboratory of Se-enriched Products Development and Quality Control,Ministry of Agriculture and Rural Affairs,Ankang,725000,China

动物营养（英文）

[1]Sha Liu;Haibo Yu;Pengju Li;Chi Wang;Guohao Liu;Xiaotian Zhang;Cheng Zhang;Meng Qi;Hong Ji-.Dietary nano-selenium alleviated intestinal damage of juvenile grass carp(Ctenopharyngodon idella)induced by high-fat diet:Insight from intestinal morphology,tight junction,inflammation,anti-oxidization and intestinal microbiota)[J].动物营养（英文）,2022(01):235-248

HSe,testine,GPx4a,andGPx4b,Fuso,caproic

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