Effects of high-carbohydrate on glycolysis and tricarboxylic acid cycle in two fish species with different feeding habits

PAN Wenbo; LI Lulu; BAO Yuchen; ZHAO Yuhua

doi:10.13557/j.cnki.issn1002-2813.2025.16.010

Abstract：The study aimed to investigate the effects of high-carbohydrate on glycolysis and tricarboxylic acid cycle in Micropterus salmoides and Megalobrama amblycephala.The liver primary cell culture experiment was conducted on Micropterus salmoides(D)and Megalobrama amblycephala(T),with three treatments,control group(group CD),isotonic group(group DS),and high glucose group(group HCD).After 48 hours of cultivation,the activity of key enzymes involved in glucose metabolism and the content of intermediate products were detected.A total of 180 experimental fish with similar sizes were selected for each fish species in the feeding experiments.For each species,the fish were randomly divided into two groups,with three replicates per group and 30 fish per replicate.The groups DCD and TCD were fed with a basal diet,while the groups DHCD and THCD were fed with a high-carbohydrate diet.The results showed that compared with the groups CD and DS,the group HCD significantly elevated the activities of glucose kinase(GK),phosphofructokinase(PFK),pyruvate kinase(PK),citrate synthase(CS),isocitrate dehydrogenase(IDH),andα-ketoglutarate dehydrogenase(α-KGDH),as well as the concentrations of pyruvate(PA),isocitrate(IA),andα-ketoglutarate(α-KA)(P＜0.05).Compared with the basal diet,the high-carbohydrate diet significantly increased serum glucose(GLU)content,and lanine aminotransferase(ALT),and aspartate aminotransferase(AST)activities in two types of fish(P＜0.05),significantly increased the activities of GK,IDH,and α-KGDH,and the concentrations of IA and α-KA,significantly increased the mRNA expression levels of the glucokinase gene(gk),isocitrate dehydrogenase gene(idhi),and α-ketoglutarate dehydrogenase gene(α-kgdh)(P＜0.05).The study shows that high-carbohydrate can enhance the glycolysis and tricarboxylic acid cycle metabolism of fish by increasing the activity of key enzymes and the content of intermediate products,and the ability of herbivorous Megalobrama amblycephala to regulate glycolysis and tricarboxylic acid cycle is superior to that of carnivorous Micropterus salmoides.