| In this study,the Southern Catfish(Silurus meridionalis)larvae(weight 45.85 ±3.82g)and Grass Carp(Ctenopharyngodon idellus)larvae(weight 47.51 ± 2.87g)were objects,and starved for 0,3,7,14,21,28 days in the condition of 27.5±0.5?.In order to explore the physiological and ecological mechanisms of two different types of nutrient fish to response of starvation stress,we observed effects of experimental treatment on growth and energy metabolism of the fish.The main results were as follows:1.there was no significant change in body weight and body length of two kinds of fish after 28 days of starvation,but their condition factor decreased significantly(p<0.05).The liver organ index of two kinds of fish after 28 days of starvation were significantly lower than their initial states(p<0.05);liver organ index of Grass Carp was significantly higher than that of Southern Catfish before starvation,but the difference of liver organ index between two species was not obvious after 28 days of starvation,and the former declined more.2.Protein content of Grass Carp before treatment was significantly higher than that of Southern Catfish(p<0.05),but it was significantly lower than that of Southern Catfish after 28 days of starvation(p<0.05);but the change of fat content in two kinds of fish was contrary to their protein content.The fat content of Southern Catfish was lower than that of Grass Carp,and its protein content decreased less than Grass Carp.3.The energy density of two kinds of fish after 28 days of starvation were significantly lower than their initial states(p<0.05);energy density of Grass Carp was significantly higher than that of Southern Catfish before starvation,but the difference of energy density between two species was not obvious after 28 days of starvation.The energy budget equation of Southern Catfish: 100G=39.1E+59.59MS+1.31Ma;The energy budget equation of Grass Carp: 100G=39.58E+55.84MS+4.58 Ma.4.The resting metabolic rates(RMR)of Grass Carp were significantly higher than that of Southern Catfish in each starvation time(p<0.05),and its RMR was decreasing with the starvation time prolonged;while RMR of Southern Catfish was increased and then decreased.5.Liver mitochondrial state 3 respiration rates of Southern Catfish were decreased in starvation time,but the values of Grass Carp were increased;the former was significantly higher than the latter in initial state,but after starvation for 28 days the former was significantly lower than that of the latter(p<0.05).Brain mitochondrial state 3 respiration rates of Southern Catfish were increased with the prolongation of starvation time,while Grass Carps' were declined;kidney and heart mitochondrial state 3 respiration rates of two fish were decreased with the prolongation of starvation time;mitochondrial state 3 respiration rates in the heart of Southern Catfish in each of detection time were less than Grass Carp,but the values of the kidney were significantly higher than that of Grass Carp(p<0.05).Brain mitochondrial state 3respiration rate of Southern Catfish were significantly lower than that of Grass Carp befor sravation,but after starvation for 14 days,brain mitochondrial state 3 respiration rates of Southern Catfish were significantly higher than that of Grass Carp(p<0.05).The change of activity of cytochrome C oxidase in each tissue was similar to mitochondrial 3 respiration rate.The main conclusion were as follows:1.It show that Southern Catfish and Grass Carp have specific tissue and specific species of physiological ecology mechanism to fight with hunger stress.2.By discussion,it is conclued that Southern Catfish and Grass Carp have different types of nutrition,especially predatory behavior pattern,so they have the differen evolution of energy ecological strateges to adapt starvation stress;3.the results of this study support carnivorous fish more resistant to hunger than herbivorous fish. |
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