| China is a large country in aquaculture and has a huge demand for feed.In recent years,the proportion of aquatic feed in China’s commercial feed production has reached about 10%.In 2018,China’s aquatic feed output increased to 22.11 million tons,and the output is still increasing year by year.Nile tilapia,commonly known as African catfish,belongs to the Cichlid family Cichlididae.It was introduced in China in the late stage.The tilapia has strong environmental adaptability,short breeding cycles,fast growth,rich nutrition and delicious meat.It is very popular in the aquaculture industry,and it is often used as a model animal in the scientific research field.Vitamin E is a fat-soluble vitamin that is an indispensable and important factor in the application of fish feed formulations.Vitamin E deficiency can cause symptoms or diseases such as muscular dystrophy and hemoglobin breakdown in farmed fish.At present,research on the antioxidant and immunoregulatory properties of vitamin E is extensive in the aquatic field,but there are few studies on the effects of vitamin E on fish from molecular water products.Therefore,the first part of this experiment is to explore the effect of vitamin E deficiency on the transcriptome of tilapia liver from the perspective of vitamin E deficiency.The second part is to discuss whether the high content of vitamin E and the culture time will affect the composition of the Gut microbes of tilapia by adding high content of vitamin E.In the first part of the experiment,Nile tilapia was fed with 0 vitamin E supplemented compound feed and 50 mg / kg vitamin E supplemented compound feed for 8 weeks of breeding experiments,and then RNA-Seq technology was used.The Nile tilapia liver transcriptome was sequenced.A total of 1,279,964 clean reads were obtained from the sequencing results,and 359 genes with significant differential expression were screened out,of which 189 differentially expressed genes were significantly up-regulated and 170 differential genes were significantly Down.Among them,Ubc7,Ubc6,Hrd1,UBE2G2,HRD1,Ubc H5,TAK1,MHC,Cyt C,APC,PKA,APOB,APOA and other genes were significantly up-regulated,PRSS,CTRL,CELA,CPA,CPB,p53,STAT,IRF6,Ins,etc.Significant down-regulation occurred.These differentially expressed genes are closely related to immune function and lipid transport and accumulation.The results of the transcriptome were verified by q PCR.Further research on the function of differentially expressed genes found that the differential genes are mainly enriched with two GO functional categories: molecular function and biological process.The KEGG pathway enrichment analysis of differential genes found that the differential genes are mainly concentrated in pathways related to antioxidant and immune,including pancreatic secretion pathway,protein processing pathway in endoplasmic reticulum,lipid digestion and absorption pathway,herpes simplex Viral infection pathway,HTLV-I infection pathway.This indicates that vitamin E deficiency may have a significant effect on the antiviral mechanism of Nile tilapia immune regulation.The results of this experiment will help to better understand the application of vitamin E in fish feed formulation and improve the production efficiency of aquaculture animals.In the second part of the experiment,tilapia feed was made with 100 mg/kg of vitamin E supplementation,and a two-week breeding experiment was conducted.Three batches of fish were sampled at two-day intervals to separate the samples into different To investigate whether the addition of high levels of vitamin E and the different culture times will have a significant effect on the structure of the intestinal flora of tilapia.Through the analysis of alpha diversity and Beta diversity of each group of samples,it was found that the differences in microbial abundance and diversity in individual samples in different breeding periods were not significant.After analyzing the differences between the experimental group and the control group,it was found that the change in AKKermansia in the experimental group and the control group was significantly different,and it was a biomarker that reflected the differences between the two groups.Conclusion: Vitamin E deficiency has a significant effect on the antiviral ability of Nile tilapia,and its effect may be through the three key genes of p53,STAT1,and IRF6.In addition,vitamin E deficiency may cause differential expression of a variety of pancreatic digestive enzyme expression genes,thereby causing the Nile tilapia to digest and absorb nutrients.In terms of intestinal microbes,feeding a compound feed supplemented with 100mg/kg of vitamin E will not significantly affect the structure and composition of the intestinal flora of Nile tilapia. |
