Carbohydrates are the most economical source of energy in fish feeds, but most fish have limited ability to utilize carbohydrates. It has been reported that phosphoenolpyruvate carboxykinase 1 (pck1) is involved in carbohydrate metabolism, lipid metabolism, and other metabolic processes. However, direct evidence is lacking to fully understand the relationship between pck1 and glucose and lipid metabolism. Here, we generated a pck1 knockout zebrafish by CRISPR/cas9 system, and a high-carbohydrate diet was provided to 60 days post-fertilization (dpf) for 8 weeks. We found that pck1-deficient zebrafish displayed decreased plasma glucose, elevated mRNA levels of glycolysis-related genes (gck, pfk, pk), and reduced the transcriptional levels of gluconeogenic genes (pck1, fbp1a) in liver. We also found decreased triglyceride, total cholesterol, and lipid accumulation and in pck1-/- zebrafish, along with downregulation of genes for lipolysis (acaca) and lipogenesis (cpt1). In addition, the observation of HE staining revealed that the total muscle area of pck1-/- was substantially less than that of WT zebrafish and real-time PCR suggested that GH/IGF-1 signaling (ulk2, stat1b) may be suppressed in pck1-deficient fish. Taken together, these findings suggested that pck1 may play an important role in the high-carbohydrate diet utilization of fish and significantly affected lipid metabolism and protein synthesis in zebrafish. pck1 knockout mutant line could facilitate a further mechanism study of pck1-associated metabolic regulation and provide new information for improving carbohydrate utilization traits.
Keywords: CRISPR/cas9; Glycolipid metabolism; Protein synthesis; Zebrafish; pck1.
© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.