Effect Of Dietary Protein?Carbohydrate To Lipid Ratios? Fe Sources And Cu Sources On Nutrition Physiological Function Of Juvenile Pearl Gentian Grouper ( Epinephelus Lanceolatus?×E.Fuscoguttatus?)

8-week feeding trial of juvenile pearl gentian grouper?Epinephelus lanceolatus?×E.fuscoguttatus??with an initial average weight of?6⁹?g was conducted to assess the correlation of the dietary protein to growth of juvenile pearl gentian grouper,serum hormone and digestive enzyme activities,what could to explain the effects of dietary protein levels on healthy growth.To evaluate the growth performance,feed utilization,serum indexes,digestive enzyme activity and glycolipid metabolism,and intent to seek an appropriate carbohydrate to lipid ratios?CHO:L ratios?to meet maximize the use of non-protein energy for growth of fish.To investigate the effects of three kinds Fe sources and Cu sources on growth,antioxidant enzymes,elements contents and intestinal morphology.The experimental results of this paper are as follows:1.Grouper[average body weight?6.50±0.00?g]were randomly divided into 6groups with 4 replicates in each group.The fish were fed isoenergetic and isolipidic experimental diets with protein levels 35%,40%,45%,50%,55%and 60%,respectively.The results showed that weight gain ratio?WGR?and specific growth rate?SGR?of the fish fed with 50%protein diet were significantly higher than those of fish fed other protein level diets?P<0.05?.The concentrations of total protein?TP?in 50%group and 60%group were significantly higher than 35%group?P<0.05?.The concentration of growth hormone?GH?and Insulin?INS?in 50%group was significantly lower than than that in other groups?P<0.05?.The highest Insulin-like growth factors-??IGF-??concentration was found in 45%group and significantly higher than than that in other groups?P<0.05?.Pepsin and intestinal trypsin activities in 50%group was significantly higher than than that in other groups?P<0.05?.With increasing dietary protein levels,intestinal amylase activities was decreased,the lowest value was found in 55%group and 60%group and significantly lower than than that in other groups?P<0.05?.There was extremely significantly negative correlation between WGR and GH.According to these results,Based on broken-line regression analysis of WGR,a diet containing 51.57%protein is recommended for efficient growth of juvenile pearl gentian grouper.2.Six isonitrogenous?50.27%?experimental diets were formulated using red fish meal,dehulled soybean meal,wheat gluten flour and chicken powder as protein sources,fish oil,soybean oil and soybeam lecithin as lipid sources,corn starch as carbohydrate source containing various carbohydrate to lipid ratios?C/L?:0.82?1.03?1.28?1.58?1.94and 2.27.Grouper[average body weight?7.70±0.05?g]were randomly divided into 6groups with 4 replicates in each group.Resultes show that there were no significant differences in final body weight?FBW?,WGR and SGR among experimental groups?P>0.05?.The retention rate of protein?PRR?increased then decreased with increasing dietary CHO:L ratios,Fish fed the diet containing 1.03 and 1.58 CHO:L ratios higher than 2.27 C/L group?P<0.05?.Total sugar of dorsal muscle gradually decreased with dietary CHO:L ratios from 0.82 to 1.58.The Glucose?GLU?content and insulin?INS?in serum trended to increase as the dietary CHO:L ratio increased,while triglyceride?TG?,cholesterol?CHOL?content and glucagon?GC?in serum decreased.content significantly decreased with dietary CHO:L ratios increasing.Pepsin,intestinal lipase and hepatic amylase activities increased then decreased with increasing dietary CHO:L ratios.Intestinal amylase activities decreased with dietary CHO:L ratios increasing.The activities of hexokinase?HK?and 6-phosphofructokinase-1?PFK-1?significantly increased with dietary CHO:L ratios increasing,and the highest value was reached at 1.94,significantly higher than that in the other groups?P<0.05?.The activities of pyruvate kinase?PK?and citrate synthase?CS?increased and then descended as the dietary CHO:L ratio increased.The activity of phosphoenolpyruvate carboxykinase?PEPCK?decreased with dietary CHO:L ratios increasing,except 1.94 C/L group.The activities of glycogen synthase?GSase?in 1.03 C/L,1.58 C/L and 1.94 C/L groups were significantly higher than that in other groups?P<0.05?.Fish fed the diet containing 1.58 CHO:L ratio had the lowest glycogen phosphorylase?GPase?values among all treatments,significantly higher than that in other groups?P<0.05?.The activities of Carnitine palmitoyltransferas?CPT?,Acetyl-CoA Carboxylase?ACC?,Hormone sensitive lipase?HSL?and Adipose triglyceride lipase?ATGL?increased and then descended as the dietary CHO:L ratio increased,reachs the peak at dietary CHO:L ratio of 1.94 C/L group,significantly higher than that in other groups?P<0.05?.The activities of lipoprotein lipase?LPL?and hepatic lipase?HL?and Total lipase descended and then increased as the dietary CHO:L ratio increased,fish fed the diet containing 1.58 CHO:L ratio was lower than that in other groups?P<0.05?.Based on second-order polynomial regression analysis of SGR,a diet containing 1.66carbohydrate to lipid ratios recommended for efficient growth of juvenile pearl gentian grouper.3.The effects of dietary iron sulfate?FeSO₄?,glycine chelated iron?II??Fe-Gly?II???iron hydroxymethionine?MHA-Fe?on growth,morphological characteristics,antioxidative enzymes,elements content and intestinal morphology of juvenile pearl gentian grouper were evaluated.Juvenile pearl gentian grouper with the average body weight of?9.00±0.49?g were randomly divided into 3 groups with 3 replicates in each group and 30 fish in each replicate.The fish in those groups were fed isonitrogenous and isolipidic experimental diets with 3 different iron sources.The experiment lasted 8weeks.The results showed that three kinds of Fe sources were no significant influences on fish SR?WGR?SGR?P>0.05?.The condition factor?CF?in MHA-Fe group was significantly higher than that in another two groups?P<0.05?.The CAT activity of liver in MHA-Fe group was significantly higher than that in FeSO₄ and Fe-Gly?II?groups?P<0.05?.MDA activity of liver in MHA-Fe group was significantly lower than that in FeSO₄ and Fe-Gly?II?groups?P<0.05?.T-SOD activity of liver in FeSO₄ group was significantly lower than that in Fe-Gly?II?and MHA-Fe groups?P<0.05?.Fe contents of whole fish and vertebrae in MHA-Fe group were significantly higher than those in FeSO₄and Fe-Gly?II?groups.The plica height?PH?of foregut?midgut and hindgut in MHA-Fe group were significantly higher than those in FeSO₄ and Fe-Gly?II?groups?P<0.05?,the plica width?PW?of foregut,midgut and hindgut in MHA-Fe group were significantly lower than in another two groups?P<0.05?.The muscle thickness?MT?of midgut in MHA-Fe group was significantly higher than that in FeSO₄ and Fe-Gly?II?groups?P<0.05?.According to the fish growth,CAT activity,elements content and intestinal morphology,dietary adding MHA-Fe could improve antioxidant capacity of juvenile pearl gentian grouper by increasing the activity of CAT,T-SOD and reducing MDA activity,as well as iron deposition.MHA-Fe and Fe-Gly?II?can ameliorate intestinal health.4.The effects of dietary copper sulfate?CuSO₄??glycine chelated copper?Cu-Gly??copper hydroxymethionine?Cu-MHA?on growth,antioxidant enzymes and intestinal morphology of juvenile pearl gentian grouper were evaluated.Juvenile pearl gentian grouper with the average body weight of?9.00±0.00?g were randomly divided into 3groups with 3 replicates in each group and 30 fish in each replicate.The fish in those groups were fed isonitrogenous and isolipidic experimental diets with 3 different copper sources.The experiment lasted 8 weeks.The results showed that 1)The WGR?survival ratio?SR?in Cu-Gly and Cu-HMA groups were significantly higher than CuSO₄group?P<0.05?.2)The HSI and viscerosomatic index?VSI?in Cu-HMA group was significantly higher than CuSO₄ and Cu-Gly groups?P<0.05?.There was no significant difference in CF among all groups?P>0.05?.3)Cu contents of vertebrae in Cu-Gly and Cu-HMA groups were significantly higher than CuSO₄ group?P<0.05?.4)The serum concentrations of TG and low density lipoprotein cholesterin?LDLC?in CuSO₄ group was significantly higher than Cu-Gly and Cu-HMA groups?P<0.05?.And The serum concentrations of high density lipoprotein cholesterin?HDLC?in CuSO₄ group was significantly lower than Cu-Gly and Cu-HMA groups?P<0.05?.5)The activity of serum ceruloplasmin?CP?in CuSO₄ group was significantly higher than Cu-Gly and Cu-HMA groups?P<0.05?.6)The plica height?PH?of midgut and hindgut in Cu-HMA group were significantly higher than those in CuSO₄ and Cu-Gly groups?P<0.05?.According to the fish growth,morphological characteristics,serum biochemical indices,antioxidant enzymes,elements content and intestinal morphology,dietary adding Cu-Gly and Cu-HMA could improve intestinal morphology and serum lipid metabolism,and then ameliorate growth of juvenile pearl gentian grouper.