| Part 1: An 8-week feeding experiment was conducted to evaluate the effects of fishmeal replacement by soybean meal(SM)on growth performance,body composition,digestion and metabolism of juvenile hybrid grouper(?Epinephelus fuscoguttatus×?Epinephelus lanceolatus).Five isonitrogenous and isoenergetic diets were formulated by replacing 0,20%,40%,60%,80% of fishmeal protein with soybean meal(SM0 to SM80)respectively.A total of 450 juveniles with an average body weight of(47.18±0.45)g were randomly assigned into 5 groups with 3 replicates per group and 30 fish per replicate.Results showed as follows: 1)There was no significant influence on growth performance and feed utilization of juveniles when soybean meal substitution was less than 40% and the weight gain rate(WGR),specific growth rate(SGR),protein efficiency ratio(PER)and daily feed intake(DFI)of the juveniles were significantly decreased in group SM60 and group SM80(P<0.05).2)With the increasing of dietary soybean meal content,the crude protein content in whole body decreased and the values of group SM20 to group SM80 were significantly lower than that of group SM0(P<0.05),the crude ash content in whole body was significant lower when dietary soybean meal content was more than 40%,the moisture content in muscle significantly increased while crude protein and crude lipid content significantly decreased in group SM80(P<0.05),dietary inclusion of SM(SM20 to SM80)significantly reduced several amino acid content of muscle such as Met,Leu and Lys and so on(P<0.05).3)Dietary inclusion of SM(SM20 to SM80)significantly reduced intestinal trypsin activity(P<0.05),pepsin and intestinal amylase activities decreased significantly in group SM60 and group SM80(P<0.05).4)The activities of alanine transaminase(ALT)and aspartate transaminase(AST)decreased with the increasing of dietary soybean meal content and were significantly lower in group SM40 to group SM80(P<0.05),the activity of Glucose-6 – phosphatase(G6PC)was significantly higher in group SM20 and group SM40.In conclusion,Soybean meal can replace 40% of the fish meal and higher replacement level will lower the growth of juveniles.Part 2: The aim of the experiment was to determine the effects of fish meal replacement by soybean meal on serum biochemical parameters and antioxidant capacity of juvenile hybrid grouper(?Epinephelus fuscoguttatus×?Epinephelus lanceolatus).Five isonitrogenous and isoenergetic diets by replacing 0,20%,40%,60%,80% of fishmeal protein with soybean meal(SM0 to SM80)were each fed to triplicate groups of juveniles(mean initial weight 47.18±0.45g)for 8 weeks.Results showed that: The activity of aspertate aminotransferase(AST)and alanine aminotransferase(ALT)in serum were increased significantly in group SM60 and group SM80 while total protein(TP)and glucose(GLU)content were significantly decreased(P<0.05).The content of triglycerides(TG)and low-density lipoprotein(LDL)were significantly increased and high-density lipoprotein(HDL)content had the opposite trend(P<0.05)in group SM60 and group SM80.2)The serum total antioxidant capacity(T-AOC)in group SM60 and group SM80 were significantly lower than that in group SM0(P <0.05).The content of malondialdehyde(MDA)in group SM80 was significantly higher than that in group SM0(P<0.05).The T-AOC and superoxide dismutase(SOD)activity of liver were significantly decreased while MDA content was significantly increased in group SM60 and group SM80(P<0.05).In conclusion,appropriate substitution had no significant influence on serum biochemical parameters of juveniles and higher replacement could adversely affect the deposition of protein and fats and reduce antioxidant capacity of juveniles.Part3: An 8-week feeding experiment was conducted to evaluate the effects of fishmeal replacement by hydrolyzed soybean meal(HSM)on growth performance,body composition,digestion and metabolism of juvenile hybrid grouper(?Epinephelus fuscoguttatus×?Epinephelus lanceolatus).Five isonitrogenous and isoenergetic diets were formulated by replacing 0,20%,40%,60%,80% of fishmeal protein with hydrolyzed soybean meal(HSM0-80)respectively.A total of 450 juveniles with an average body weight of(47.18±0.45)g were randomly assigned into 5 groups with 3 replicates per group and 30 fish per replicate.Results showed as follows: 1)The WGR and SGR of the juveniles were increased significantly in group HSM40 while the WGR,SGR and PERin group HSM80 were significantly lower than that of other groups(P<0.05).When dietary hydrolyzed soybean meal content was more than 40%,The DFI of the juveniles were significantly increased(P<0.05).2)With the increasing of dietary hydrolyzed soybean meal content,the crude lipid content in whole body and muscle decreased and the values of group HSM40 to group HSM80 were significantly lower than that of other groups(P<0.05),the crude ash content in whole body was significant higher in group HSM40 and group HSM60(P<0.05),there was no significant difference in the content of amino acids of muscle among the replacement groups(P>0.05).3)With the increasing of dietary hydrolyzed soybean meal content the pepsin and trypsin activities increased and then decreased and were significantly lower in group HSM80(P < 0.05),the activity of lipase was significantly lower when dietary hydrolyzed soybean meal content was more than 60%.4)The activities of ALT decreased significantly in group HSM80(P<0.05),with the increasing of dietary hydrolyzed soybean meal content the activity of FAS decreased and was significantly lower in group HSM80(P<0.05),The activities of G6 PC was significantly higher in group HSM20 and group HSM40.In conclusion,replacing up to 60% of dietary fishmeal with hydrolyzed soybean meal does not reduce the growth of juvenile hybrid grouper and optimal replacement level was 40%.Part4: The aim of the experiment was to determine the effects of fish meal replacement of soybean meal on serum biochemical parameters and antioxidant capacity of juvenile hybrid grouper(?Epinephelus fuscoguttatus×?Epinephelus lanceolatus).Five isonitrogenous and isoenergetic diets by replacing 0,20%,40%,60%,80% of fishmeal protein with hydrolyzed soybean meal(HSM0 to HSM80)were each fed to triplicate groups of juvenile s(mean initial weight 47.18±0.45g)for 8 weeks.Result showed that:1)The activity of ALT in serum was significantly decreased in group HSM40 and group HSM60(P<0.05),the content of ALB in HSM40 and HSM60 group were significantly increased(P<0.05),The contents of CHO?TG and LDL in group HSM60 and HSM80 were significantly decreased(P<0.05).2)The serum T-AOC in group HSM20 was significantly higher than that in other groups(P<0.05),the activity of SO D in group HSM60 and HSM80 were significantly increased(P<0.05).The T-AOC of liver in group HSM40 and the activity of SOD in group HSM40 and HSM60 were significantly increased(P<0.05),and the content of MDA in HSM60 and HSM80 group was significantly decreased(P<0.05).In conclusion,HSM could promote the synthesis and metabolism of protein and could improve the fat accumulation and improve the antioxidant capacity of juveniles. |
PDF Full Text Request