| In order to develop a feed suitable for the production of juvenile blunt snout bream(Megalobrama amblycephala)nutritional balanced diet and vitamin compatibility on high temperature pull reticulum stress.This study was conducted to investigate the effects of six different dietary on growth index,anti-stress indicators,immunity,and antioxidant capacity and anti-stress-related gene expression of juvenile blunt snout bream(Megalobrama amblycephala).The experiment included two parts:Part 1 Effect of feed vitamins and fat levels on growth performance and body composition of juvenile blunt snout bream(Megalobrama amblycephala)Six groups isonitrogenous feed were produced,Dl:basal diet(fat content is 5%)+vitamin formula 1;D2:basal diet(fat content is 5%)+ vitamin formula 2;D3:basal diet(fat content is 5%)+ vitamin formula 3;D4:basal diet(fat content is 7%)+ vitamin formula 3;D5:basal diet(fat content is 7%)+ vitamin formula 3+choline +VC;D6:basal diet(fat content is 5%)+ vitamin formula 1+ Anti-stress additive.Four hundred and eighty fishes(average initial weight:74.98 ±0.04 g)were fed 3 times(8:00,11:30,16:00)daily for 8 weeks indoor at first,then transferred to outdoor feed 6 weeks.Each diet was tested in four replicates,and each replicate had 20 fishes.The results showed that the water temperature was low,and fishes grow lowly,and had high feed conversion ratio indoor.Weight gain of group 2 was significantly higher than D1、D4、D5、D6(P<0.05).It showed good growth speed at a low temperature(22 ℃).There were not significantly different(P>0.05)between D1、D3、D4、D6.Weight gain of D5 was the lowest.FCR of D5 was significantly higher than the other groups(P<0.05),other groups were not significant(P>0.05).After 8 weeks of indoor cultivation,we transferred the fishes to the corresponding outdoor cages(1mXlm Xlm)and fed six weeks.This phase of the water temperature gradually increased and stabilized at 32℃,The results showed that weight gain of D3 was significantly higher than the other groups(P<0.05)after six weeks fed,other groups were not significant(P>0.05),FCR of outdoor stage is significantly lower than the indoor cultivation stage,FCR of D5 was significantly higher than the other groups(P<0.05),other groups were not significant(P>0.05).D4 had the lowest FCR.Effect of six groups on body composition as follows:D4 had the lowest water content,no significant difference(P>0.05)between other groups;the group 4 had the highest fat content,was significantly higher than D3,D5,D6(P<0.05).Therefore,under the same conditions,the D4 had a good growth performance.Part 2 Effect of feed vitamins and fat levels on pull reticulum stress of juvenile blunt snout bream(Megalobrama amblycephala)This study was conducted to investigate the effects of six different feed on juvenile blunt snout bream(Megalobrama amblycephala)anti-stress indicators,immunity,antioxidant capacity and influence with the expression of anti-stress-related genes.The conceptual design was the same to the first experiment.The results showed that the difference between the pre-stress treatment groups was not significant(P>0.05),The blood glucose content of D2,D4 and D6 are less than the other three groups.The blood glucose levels were increased significantly after the stress(P<0.05);Cortisol levels of D2 was significantly lower than other groups(P<0.05)before the stress test,and significantly increased(P<0.05)after the stress,cortisol levels of D1 did not change substantially after the stress,Cortisol levels of D3 had increased after stress,Cortisol levels of D4 decreased slightly after stress,D5 and D6 cortisol levels were decreased after stress;The lactate levels of plasma were increased significantly(P<0.01)in each groups after the stress.The plasma NO content of the D4 was significantly lower than other groups(P<0.05)before stress,but it had significantly increased(P<0.05)after the stress and its content is higher than other groups(P<0.05),The NO content of D1 and D6 increased slightly after stress,The plasma NO levels of D2,D3 and D5 have declined after stress.Before stress.The plasma CAT content of D1,D4 were higher than other groups,They had significantly increased(P<0.05)after the stress.The plasma CAT content of group were higher than other groups except D6,The plasma CAT content of D6 was significantly increased(P<0.05)after stress;The plasma MDA content of D3 was significantly higher than other groups(P<0.05)before the stress,The plasma MDA content have decreased after stress except D1 and D5;The plasma GPT content had significantly increased(P<0.05)after the stress,The D3 and D5 plasma GPT content had higher then other groups,and the other groups were not significant(P>0.05);The plasma GOT content of each groups had significantly increased(P<0.01)after stress;The liver HSP70 and TNF-a gene expression levels of each groups had significantly increased(P<0.05)after stress;the difference between treatment groups was not significant(P>0.05),The liver HSP70 expression of D2,D4,D6 had a obvious rise,the other three groups of HSP70 expression also increased;The liver gene expression of TNF-a of each groups had significantly increased(P<0.05),The liver TNF-α gene expression of D1 and D2 were higher than other groups,the gene expression of D2 significantly increased significantly(P<0.05).The results showed that under the high temperature and net stress,Optimizing vitamin compatibility can have a strong anti-stress. |
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