Study On The Difference Of Shape,respiratory Physiology And Organ Function Enzyme Activity Between Different Weight Gain Performance Groups Of Juvenile Black Seabream

The Sparus macrocephalus juvenileof 2 months old[body mass?0.7-16.7g?,body length?4-9cm?]were chosen to be the experimental objects,and 3,000 randomly selected Sparus macrocephalus juvenile from the same pool were weighed according to 5%,20.6%,48.3%,21.0%and 5.2%.They were divided into five groups of A?6.8-16.7g?,B?4.5-6.7g?,C?2.8-4.4g?,D?2-2.7g?,E?0.7-1.9g?in descending order,then the effects of phenotypic frame traits on body mass and net body mass were measured in five groups of weight gain performance,29 phenotypic trait differences,back muscle texture characteristics,oxygen consumption rate and asphyxiation point differences in visceral tissue digestive enzyme activity,sputum and total visceral tissue antioxidant enzymes and ATPase activity.?1?Determination of phenotypic framework traits of Sparus macrocephalus juvenile with different weight gain.After the correlation analysis and the path analysis,the body length,anal length,head width and DE are the main phenotypic traits affecting group A.Body length,head length,head height,CD and GH are the main phenotypic traits affecting group B.Head width and lateral length are the main phenotypic traits affecting group C.Body length,anal length,head width and AN are the main phenotypic traits affecting group D.Body length is the main phenotypic trait affecting group E.Body length and head width are the main phenotypic traits affecting the whole population.The multiple regression equations affecting the five groups and taking A,B,C,D,and E as a whole are as follows:A:BW=0.174L₂+0.603L₈+0.254DE-11.842NW=0.124L₂+0.096L₄+0.456L₈+0.238DEB:BW=0.148L2+0.222L6-0.086CD+0.142GH-6.33NW=0.099L₂+0.197L₆+0.089L₇+0.09GH-7.677C:BW=0.072L₃+0.188L₈-0.574NW=0.135L3-1.849D:BW=0.128L₂+0.081AN-1.936 NW=0.028L₂+0.076L₃+0.111L₈+0.041AN E:BW=0.089L₂-2.566NW=0.082L₂-2.443Overall:BW=0.177L₂+0.487L₈-7.818NW=0.145L₂+0.274L₈-6.414;?2?The determination of 29 morphological traits measured in this study reached significant difference and both showed A>B>C>D>E?P<0.05?;among the 28morphological proportion indicators,The index similarities of A-B,C-D,D-E,AC,BC,and CE were 75%,50%,43%,21%,18%,and 10%respectively.The C25?Fulton's index?and C26?heavy and long index?ratios achieved significant differences and both showed A>B>C>D>E?P<0.05?;Principal component analysis was carried out on the proportion of morphology,and 5 principal components were extracted,and the cumulative contribution of variance was 82.358%;The experimental group A was defined as fast-growing group.The experimental groups B,C,D,and E were classified into common groups.By discriminant analysis,the discriminant variables of C9?head width/body length?,C10?head height/body length?,C13?eye diameter/body length?,C17?tail length/body length?,and C18?tail height/body length?were the Fisher classification function,the comprehensive discriminant rate of which was 96.25%.?3?After texture analysis,the hardness of the back muscles of the five groups of experimental juveniles showed A>B>C?D>E,the adhesion showed A<B<C<D?E,and the elasticity showed A>B>C.>D?E,both cohesiveness and recovery showed A>B>C?D>E,chewiness showed A>B>C>D>E,and the index similarity of CD and DE was 50%and 40%.There were significant differences in hardness,adhesion,elasticity,cohesiveness,chewiness and recovery between the other three groups and the fast-growing groups of A and B?P<0.05?.?4?The mean night,mean day,and average daily oxygen consumption rate of the five groups of juveniles were determined.The oxygen consumption rate and the oxygen content of the asphyxiation point increased with the decrease of the weight gain performance of juvenile fish.The visceral protease activity,lipase activity and amylase activity of Sparus macrocephalus juvenile showed A?B?C?D<E,A?B<C<D?E and A<B?C<D?E respectively;The enzyme activities of SOD,POD and CAT in the whole viscera of Sparus macrocephalus juvenile were A<B?C?D<E,and the activities of antioxidant enzymes SOD,POD and CAT of alfalfa were A?B>C?D?E,A>.B>C>D?E and A?B>C?D?E;The Na⁺/K⁺-ATPase activity and Ca²⁺/Mg²⁺-ATP enzyme activity of whole viscera were A<B?C<D?E and A<,respectively.B?C?D?E,the Na⁺/K⁺-ATP and Ca²⁺/Mg²⁺-ATPase activities in gills were A?B>C?D?E.