This study aimed at investigating the effects of dietary protein levels on the growth and liver transcriptome in juvenile Ancherythroculter nigrocauda. Six semi-purified diets were formulated containing 25 (control), 30, 35, 40, 45, and 50% protein. Each diet was fed to three groups of 35 fish (mean initial weight: 5.86 ± 0.10 g) for 56 days. The rate of weight gain and specific growth rate increased with dietary protein levels from 25% to 40%, but remained unchanged when fed with 45 or 50% dietary protein. The feed conversion ratio was significantly influenced by the dietary protein levels, being the lowest in fish fed 40% protein. Illumina RNA-seq analysis was performed to investigate liver gene expression changes under different dietary protein treatments. A total of 367.78 million clean reads were obtained from the six libraries. Compared with 25% protein treatment library, there were 734, 1946, 1755, 2726, and 1523 upregulated genes, and 407, 1882, 1865, 2216 and 1624 downregulated genes in the 30, 35, 40, 45, and 50% protein treatment libraries, respectively. Trend analysis of these differentially expressed genes (DEGs) identified six statistically significant trends. A series of DEGs that related to protein metabolism, growth and development, lipid metabolism and immune and stress response were identified. Moreover, gene ontology enrichment analysis of the DEGs demonstrated that cellular process, single-organism process, metabolic process and biological regulation were the most highly overrepresented biological processes. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that protein processing in endoplasmic reticulum, PPAR signaling pathway, complement and coagulation cascades, and cytochrome P450 (CYP450s) were significantly enriched in the dietary protein treatment groups. Furthermore, qPCR results showed excellent agreement on those of RNA-seq for both up- and down-regulated genes (including fasn, accα, SCD, CPT-I, igf1, ST, AST, trdmt1, hsp70, cyp450, MHC-II, C4, tgfβ, ube4b, apoE and abcb7). Thus, our results provide the baseline information for the feed formulation and nutritional research for A. nigrocauda.

这项研究旨在调查日粮蛋白水平对黑An鱼的生长和肝脏转录组的影响。配制了六种半纯饮食，其中含有25％（对照），30％，35％，40％，45％和50％的蛋白质。将每种饮食喂给三组，每组35条鱼（平均初始重量：5.86±0.10 g），持续56天。饮食蛋白质水平从25％增加到40％，体重增加率和比生长率增加，但以45％或50％饮食蛋白质喂养时，体重增加和特定生长率保持不变。饲料转化率受日粮蛋白质水平的显着影响，在饲喂40％蛋白质的鱼中最低。进行Illumina RNA-seq分析以研究在不同饮食蛋白处理下肝脏基因表达的变化。从这六个库中总共获得了367.78百万次干净读取。与25％的蛋白质处理文库相比，共有734、1946、1755、2726和1523个上调基因，以及407、1882、1865，2216和1624分别下调了30％，35％，40％，45％和50％蛋白质处理库中的基因。这些差异表达基因（DEG）的趋势分析确定了六个统计学上显着的趋势。鉴定了一系列与蛋白质代谢，生长和发育，脂质代谢以及免疫和应激反应有关的DEG。此外，DEGs的基因本体论富集分析表明，细胞过程，单一生物过程，代谢过程和生物调节是最高度代表的生物过程。京都基因与基因组百科全书》的富集分析显示，在饮食蛋白处理组中，内质网中的蛋白加工，PPAR信号通路，补体和凝血级联以及细胞色素P450（CYP450s）显着丰富。fasn，accα，SCD，CPT - I，igf1，ST，AST，trdmt1，hsp70，cyp450，MHC - II，C4，tgfβ，ube4b，apoE和abcb7）。因此，我们的研究结果为黑曲霉的饲料配方和营养研究提供了基础信息。