| Experiment 1 A 8-Week feeding trial was conducted to evaluate the effects of dietary Skimmed Krill Meal(SKM)on the growth performance,blood biochemical parameters and non-specific immunity of juvenile spotted halibut(Verasper variegatus)The basal diet was formulated using fish meal,Skimmed Krill meal as the main protein and fish oil as the lipid,respectively.A control diet(R0)without SKM,and other six diets with 6.33%(R10),12.66%(R20),18.99%(R30),25.32%(R40),31.66%(R50)and 63.31%(R100)of SKM supplementation in diets(10%,20%,30%,40%,50% and 100% replacement of fish meal protein)were fed to seven groups of 60.11±0.13 g juvenile spotted halibut.Results showed that 1 the specific growth rate,survival rate and feed efficiency of R10-R50 group were not significantly different from those of R0 group(P> 0.05),but decreased from R30 group.The Hepatosomatic index and Viscerosomatic index of R10-R30 group were not significantly different from those of R0 group(P> 0.05).2 The serum acid phosphatase in R10-R20 group was significantly higher than that in R0 group(P <0.05).The serum acid phosphatase of R30 group was not different from that of R0 group(P> 0.05).The serum alkaline phosphatase in R30-R100 group was significantly higher than that in R0 group(P <0.05).The serum SOD of R10 group was not different from that of R0 group(P> 0.05).The liver acid phosphatase in R10 group was significantly higher than that in R0 group(P <0.05).The liver alkaline phosphatase of R30-R40 group was not significantly different from that of R0 group(P> 0.05).The liver SOD of R10-R40 group was not significantly different from that of R0 group(P> 0.05).3 The serum total protein of R10-R50 group was significantly higher than that of R0 group(P <0.05).Viscerosomatic index and glutamate dehydrogenase of juvenile spotted halibut had no significant difference among groups(P>0.05).Above results showed that 10%~30% of Spotted krill meal levels can has same effect on growth performance,feed efficiency ratio and non-specific immunity of juvenile spotted halibutExperiment 2 In this study,a 8-week feeding experiment was conducted to determine the optimum level of skimmed krill meal(SKM,in replacement of the fishmeal)in the diet for spotted halibut,Verasper variegatus.The fishmeal and SKM were used as the main protein sources,and fish oil was used as the lipid sources.The seven isocaloric and isonitrogenous diets contained 0,10%,20%,30%,40%,50%,100% SKM.Each diet was randomly given to a triplicate of 15 fish(60.13±0.20 g)per tank in the indoor culture system.The results showed that(1)the Viscerosomatic index and Hepatosomatic index of other groups were higher than those in F100 group(P<0.05).The condition factor of F20~F30 groups was higher than that in F40 group(P<0.05).(2)The whole-body moisture and ASH of F100 group were higher than those of other groups(P<0.05).The whole-body crude protein of F10 and F100 groups was higher than that in other groups(P<0.05).The whole-body crude fatty of F30 and F50 groups was higher than that in other groups(P<0.05).The muscle moisture of F10,F20 and F50 groups was higher than that of F100 group(P<0.05).The muscle crude protein and ash of F10~F100 groups was not different from those of F0 group(P>0.05).The muscle crude fat of F20~F30 groups was higher than that in those groups(P<0.05).(3)The pepsin of juvenile spotted halibut had no significant different among groups(P>0.05).The stomach lipase of F0 and F20 groups was lower than that of F30 group(P<0.05).The stomach amylase of F30 group was higher than that of other groups(P<0.05).The intestines amylase of F0 was significantly higher than that of other groups(P<0.05).The intestines lipase of F30 and F100 groups was lower than that of other groups(P<0.05).(4)The fold height of F30 was significantly higher than that of other groups(P<0.05).The mucosa thickness and villus length of juvenile spotted halibut had no significant different among groups(P>0.05).Above results showed that 10%~50% of spotted krill meal levels can has same effect on body composition,digestive ability of juvenile spotted halibutExperiment 3 A 8 weeks experiment was conducted to investigate the effects of dietary fish oil(FO)replacement by soya-bean oil(SO)on growth,lipid deposition and fatty acid composition of juvenile spotted halibut adding krill oil or not.Eight isonitrogenous and isolipidic practical diets were formulated with SO replacing 0,25%,50% and 75% FO,respectively.A total of 720 juvenile spotted halibut with the initial body weight of(65.47±1.57)g were randomly distributed into 8 groups with 3 replicates per group and 30 fish per replicate,and the fish in each group were randomly fed one of four experimental diets.The results showed as follows: 1 the weight gain rate and feed conversion rate of spotted halibut were significantly affected by SO replacement level(P>0.05).2 Adding krill oil or not,SO replacement level had no significant effects on body composition and muscle lipid content of juvenile spotted halibut(P>0.05),but had significant effect on liver lipid content of juvenile spotted halibut(P<0.05).3 Adding krill oil or not,Fatty acid composition in muscle showed a positive correlation with dietary fatty acid composition.Compared with 100% FO group,the contents of linoleic acid(C18:2n-6)and linolenic acid(C18:3n-3)in muscle were significantly increased(P<0.05),while the contents of eicosapntemacnioc acid(EPA)and docosahexaenoic acid(DHA)in muscle were significantly decreased(P<0.05).this study suggested that there were no significant effects of replacement of dietary fish oil by soya-bean oil on growth of juvenile spotted halibut.However,the fatty acid composition of muscle were significantly influenced.Experiment 4 A 8 weeks experiment was conducted to investigate the effects of dietary fish oil(FO)replacement by soybean oil(SO)on Lipometabolism,non-specific immunity and anti-stress of juvenile spotted halibut adding krill oil or not.Eight isonitrogenous and isolipidic practical diets were formulated with SO replacing 0,25%,50% and 75% FO,respectively.A total of 720 juvenile spotted halibut with the initial body weight of(65.47±1.57)g were randomly distributed into 8 groups with 3 replicates per group and 30 fish per replicate,and the fish in each group were randomly fed one of four experimental diets.The results showed as follows: 1 Compared with 100% FO group,the contents of cholesterol and low density lipoprotein in serum were significantly increased(P<0.05),while the contents of triglyceride and high-density lipoprotein in serum were significantly decreased(P<0.05).with adding krill oil,the contents of cholesterol and low density lipoprotein in serum were significantly decreased(P<0.05),while the contents of triglyceride and high-density lipoprotein in serum were significantly increased(P<0.05).the lipoprotein lipase,hepatic lipase and total lipase of spotted halibut were not significantly affected by SO replacement level(P>0.05).2 SO replacement level had significant effects on SOD,lysozyme and catalase in soybean lecithin group(P<0.05),but had no significant effect on that in krill oil group(P>0.05).3 the survival of S75 group was lower than that of other groups(P<0.05),and survival of K25-K75 groups were similar to those of K0 group(P>0.05).this study suggested that there were significant effects of replacement of dietary fish oil by soybean oil on lipometabolism,non-specific immunity and anti-stress of juvenile spotted halibut.if adding krill oil in diet,this condition will be good. |
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