GAO Zihan, WEI Wei, YUE Miao, LI Yixin, CUI Yanrong, XU Baoke, LI jin, WEI Fulei, LIANG Jian
To inquire mechanism of Gymnocypris przewalskii adaptation to alkalinity changes through glucose metabolism,G. przewalskii with body weights of 126.67 g±8.88 g were reared in an 85 cm×56 cm×62 cm tank containing either freshwater (control group) or four experimental alkalinities of 25%,50%,75% and 100%,prepared using NaHCO3 and Na2CO3 dissolved in tap water (NaHCO3∶Na2CO3 = 9∶1).The important indicators of G. przewalskii glucose metabolism were determined,including glycogen content,glucose (GLU) content,and the activities of pyruvate (PA),hexose kinase (HK),pyruvate kinase (PK),phosphoenolpyruvate (PK),phosphoenolpyruvate carboxylase (PEPCK),glucose 6 phosphate dehydrogenase (G6PD),and fructose 1,6 bisphosphate aldolase (FBA).The results showed that,with increasing alkalinity,the hepatic glycogen,muscle glycogen,and GLU content in the gills and kidneys increased and then decreased,and the GLU in the muscle gradually decreased.As the alkalinity increased,PA in the gills increased and then decreased,and PA in the kidneys,liver,and muscle decreased and then increased.The activities of HK,PK,PEPCK and G6PD in the gills showed an increasing trend with increasing alkalinity,and the activities of FBA in the kidneys and liver gradually rose.A heatmap showed that glucose metabolism processes in the gills,kidneys,and liver were promoted by increasing alkalinity to some extent,while glucose metabolism in the muscle was inhibited as alkalinity increased.As alkalinity increased,fba-c was commonly expressed in the gills,kidneys,intestine,and liver,and the expression level of fba-c in the gills and kidneys increased and then decreased.The maximum expression levels were observed in the 75% alkalinity group.In conclusion,the gills,kidneys,and liver responded to alkalinity changes by increasing glucose metabolism,while muscle responded to alkalinity changes by inhibiting glucose metabolism,leading to rapid adaptation to different alkalinity levels in G. przewalskii.
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in the cultured water (P<0.05),and significantly increased the growth rate and specific growth rate of L. vannamei by 16.32%,17.52%,and 40.18%.and 40.06%,respectively.There was no significant difference in survival rate among the three groups (P>0.05).The richness of the L. vannamei intestinal flora and the water flora is significantly increased in the experimental group (P<0.05).The addition of the XYB4 strain inhibited the growth of harmful bacteria,such as Photobacterium and Tenacibaculum,and promoted the growth of beneficial nitrifying bacteria,such as Nitrospirae.In conclusion,the application of XYB4 can effectively reduce the concentrations of 
