Abstract: An 8-week feeding trial was conducted to evaluate the effects of dietary carbohydrate sources including cassava starch (CS) and wheat starch(WS), and carbohydrate/protein ratio (C/P) on growth performance, food utilization, carbohydrate metabolic enzyme activities, and regulatory factor contents related to glycometabolism, including insulin receptor(IR), glucose transporter(GLUT2) and hexose kinase (HK) mRNA expression levels in hepatopancreas, and GLUT2 and sodium, potassium and glucose co-transporters (SGLT1) mRNA expression levels in intestine of common carp Cyprinuscarpio. Common carp juveniles with initial body weight of (55.73±3.55)g were reared in a 1.0 m ×1.0 m×1.5 m net cage and fed isolipidic and isoenergetic diets with C/P of C5%/P32%, C10%/P30%, and C20%/P28% prepared by CS and WS at water temperature of 28-32 ℃. The maximal amylase activity was observed in midgut of the juveniles fed the diets containing CS and WS in the C10%/P30% group, significantly higher than that in C20%/P28% group (P<0.05). In the fish fed the diets containing CS, there were significantly higher hepatopancreas phosphofructokinase (PFK) and pyruvate kinase (PK) activities, and lower phosphoenopyruvate carboxykinase (PEPCK) activity in C10%/P30% group than those in C5%/P30% group (P<0.05). The maximal serum insulin (INS) level was found in C10%/P30% group and the maximal glucagon (GC) level in C20%/P28% group, significantly higher than those in other groups (P<0.05). In the fish fed the diets containing WS, however, there were significantly higher activities of PFK, glucose-6-phosphate dehydrogenase (G6PD), PEPCK，and glycogen synthase (GS) in C5%/P32% group than those in C20%/P28% group(P<0.05). Fish fed CS diets had significantly higher glucose level than the fish fed WS diets did at the same C/P ratio (P<0.05). In the fish fed the diets containing CS, the GLUT2 and HK mRNA expression levels were significantly higher in hepatopancreas of the fish in C10%/P30% group than in other groups, while IR mRNA expression level was significantly higher in C10%/P30% group than that in C5%/P32% group (P<0.05). Fish fed the CS diet had significantly higher SGLT1 and HK mRNA expression levels in C10%/P30% group than fish fed WS diet in other goups did (P<0.05). No significant differences in mRNA expression levels of IR, GLUT2 and HK were found in the juveniles fed the diets containing WS at all C/P ratios(P>0.05). There was significantly higher SGLT1 mRNA expression level in intestine of the fish fed the diets containing CS than that in the fish fed the diets containing WS at the same C/P ratio(P<0.05). The findings indicated that CS and WS have superior protein-sparing effect at the appropriate dietary carbohydrate to protein ratio, CS being better than WS.
孙金辉, 范泽, 崔培, 程镇燕, 白东清, 乔秀亭. 不同类型淀粉及糖蛋白质比对鲤糖代谢能力的影响[J]. 大连海洋大学学报, 2019, 34(2): 220-227.
SUN Jin-hui, FAN Ze, CUI Pei, CHENG Zhen-yan, BAI Dong-qing, QIAO Xiu-ting. Effects of dietary carbohydrate sources and carbohydrate/protein ratios on carbohydrate metabolism of common carp. Journal of Dalian Ocean University, 2019, 34(2): 220-227.
2019, Vol. 34 
