Abstract:The purpose of this study is to explore the absorption and utilization of plant protein in artificial diets of Chinese perch.A total of 81 experimental fish with an initial weight of 13.83±0.93 g were selected to carry out the gavage feeding experiment for a week.Nine fluid isonitrogenous and isoenergetic diets,with different dietary protein resources were designed,including fish meal as the control group (FM),12.5% rapeseed meal substitution group (R12),37.5% rapeseed meal substitution group (R37),R12 supplemental with L-lysine or L-methionine (R12+L or R12+M),R37 supplemental with L-lysine or L-methionine (R37+L or R37+M),and R12 or R37 co-supplemental with L-lysine and L-methionine (R12+LM or R37+LM).The results indicated that high level rapeseed meal substitution would damage the intestinal mucosa structure and decrease the intestinal enzyme activities of Na+-K+-ATP,then restrain the intestinal absorption and transportation.But lysine supplement would effectively alleviate intestinal damage and improve intestinal absorption.Besides,it could lead to down-regulation of the adenosine monophosphate deamination enzyme (AMPD1) mRNA expression and reduce the catabolism of free amino acids,which promoted amino acid retention for protein synthesis in the muscle.However,low level rapeseed meal substitution wouldn’t affect intestinal mucosa structure and enzyme activities of Na+-K+-ATP.Lysine supplement could accelerate intestinal transportation efficiency,at the same time,lysine and methionine co-supplementation could reduce the glutamic acid dehydrogenase (GDH) mRNA expression in the liver,to further decelerate the deamination of free amino acids in the liver and promote protein synthesis,which was conducive to the growth of fish.In summary,this study confirmed that the rate of 12.5% rapeseed meal substitution is acceptable for Chinese perch,lysine supplement could further enhance intestinal transportation efficiency and decelerate deamination of free amino acids,which provided a theoretical basis for the feasibility of feeding Chinese perch with plant protein instead of fish meal.