Abstract As a commercial carnassial fish, largemouth bass (Micropterus salmoides) consumes a large amount of forage fish as food annually. To reduce the use of forage fish, a formulated diet was utilized in a largemouth bass culture. Although they have been improved upon for 10 years, formulated diets still cannot meet the nutritional needs of largemouth bass. The formulated diet and forage fish were separately used to feed fish in an experimental group (FDG) and control group (FFG) to investigate the effects of a commercial formulated diet on the growth performance and liver histomorphology and transcriptomics of largemouth bass. After the 8-month feeding trial, fish fed the formulated diet exhibited a significantly lower weight gain rate (WGR) and specific growth rate (SGR) but a higher hepatosomatic index (HSI) and hepatocyte vacuolization score. A further transcriptomic difference analysis demonstrated all of the physiological changes in the process of liver injury caused by the formulated diet. Several key genes involved in the process of liver disease, including gk (glucokinase), pck (phosphoenolpyruvate carboxykinase), acetyl-CoA acetyltransferase cytosolic-like (acat cytosolic-like), type-2 ice-structuring protein (type-2 isp), tf (transferrin), col6a3 (collagen type VI alpha 3), and TBT-bp (tributyltin-binding protein), showed significant differences in their expression patterns between the two diet groups. KEGG analysis showed that the differentially expressed genes in both females and males were involved in important pathways, including glycolysis, the citrate cycle (the TCA cycle), pathogenic E. coli infection and fatty acid biosynthesis. The results suggest that the extra carbohydrates in the formulated diet were transformed into fatty acids and that the synthesized fatty acids with the lipids in the formulated diet accumulated heavily in the liver, leading to inflammation and liver injury in largemouth bass.

中文翻译：

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组织学检查和转录组分析发现配方饲料中大口黑鲈的肝损伤

摘要 大口黑鲈（Micropterus salmoides）作为一种商业肉食性鱼类，每年都要消耗大量的饲料鱼作为食物。为了减少饲料鱼的使用，在大口黑鲈养殖中使用了配方饲料。尽管经过10年的改进，配方饲料仍然不能满足大口黑鲈的营养需求。实验组（FDG）和对照组（FFG）分别使用配方饲料和饲料鱼喂鱼，以研究商业配方饲料对大口黑鲈生长性能和肝脏组织形态学和转录组学的影响。经过8个月的喂养试验，饲喂配方饲料的鱼表现出显着较低的增重率 (WGR) 和特定生长率 (SGR)，但具有较高的肝体指数 (HSI) 和肝细胞空泡化评分。进一步的转录组差异分析证明了配方饮食引起的肝损伤过程中的所有生理变化。肝病过程中涉及的几个关键基因，包括gk（葡萄糖激酶）、pck（磷酸烯醇丙酮酸羧激酶）、乙酰辅酶A乙酰转移酶胞质样（acat cytosolic-like）、2型冰结构蛋白（2型isp） 、tf（转铁蛋白）、col6a3（VI 型胶原蛋白 alpha 3）和 TBT-bp（三丁基锡结合蛋白）在两个饮食组之间的表达模式上显示出显着差异。KEGG分析表明，雌性和雄性差异表达的基因参与重要途径，包括糖酵解、柠檬酸循环（TCA循环）、致病性大肠杆菌感染和脂肪酸生物合成。结果表明，配方日粮中多余的碳水化合物转化为脂肪酸，合成的脂肪酸与脂质中的脂质在肝脏中大量积累，导致大嘴黑鲈发炎和肝损伤。