Study On Dietary Of Protein And Lipid Requirement In Juvenile Dabry’s Sturgeon(Acipenser Dabryanus)

This study was conducted to research the effects of dietary protein and lipid levels on growth performance, digestive enzyme activities, blood biochemical parameters and body composition of juvenile Dabry’s sturgeon(Acipenser dabryanus), so as to estimate the optimal dietary protein level for juvenile Dabry’s sturgeon. Results are as follows:An 8–week growth trail was conducted to estimate the optimal dietary protein level for juvenile Dabry’s sturgeon(average initial weight was 400.68±8.55 g). Five isoenergetic diets were formulated to contain five levels of crude protein(30.83 %、34.31 %、39.54 %、45.58 %、50.76 %) and each diet was fed to triplicate groups of thirty fish in fifteen concretetanks. The flow rate was 6 L/min. The water temperature was 24.0±1.0 °C, dissolved oxygen concentration was over 6.0 mg/L, ammonia–nitrogen concentration was less than 0.02 mg/L during the trial. The results showed that Specific growth rate(SGR) increased firstly and then decreased with the increasing of dietary protein level. Feed conversion rate(FCR) was on the contrary, which showed decreased firstly and then increased with the increasing of dietary protein level. Protein efficiency ratio(PER) showed a tendency of indifference firstly then decreasing with increasing of dietary protein level. Viscerosomatic index and Hepatosomatic index decreased significantly with the increasing of dietary protein level. The concent of plasma triglyceride(TG) and total cholesterol(T–CHO) showed no significant difference. The activities of ALT and AST which fed 50.76 % dietary protein level showed significantly higher value than other group. The experiment showed that the dietary peotein level has a positive correlation with pepsase activities and a negative correlation with amylase activities, while there is no significant difference with lipase activities. The content of crude protein and lipid in the whole body and dorsal muscle increased with the increasing of dietary protein level. Second – order regression analysis showed that the appropriate dietary protein requirement of juvenile Dabry’s sturgeon is on a scale of 41.55 % to 43.17 %.An 8–week growth trail was conducted to estimate the optimal dietary protein level for juvenile Dabry’s sturgeon(average initial weight was 417.54±5.23 g). Five isonitrogenous diets were formulated to contain five levels of crude lipid(4.87 %、7.23 %、9.63 %、12.07 %、14.04 %) and each diet was fed to triplicate groups of thirty fish in fifteen concrete tanks. The flow rate was 6 L/min. The water temperature was 24.0±1.0 °C, dissolved oxygen concentration was over 6.0 mg/L, ammonia–nitrogen concentration was less than 0.02 mg/L during the trial. The results showed that Specific growth rate(SGR) and Protein efficiency ratio(PER) increased significantly with dietary lipid level from 4.87 % to 9.63 %(P < 0.05) and then decreased significantly(P < 0.05). Feed conversion rate(FCR) decreased significantly when the dietary lipid level increased to 9.63 %(P < 0.05) and then increased significantly(P < 0.05). Condition factor(CF) showed no significant difference(P > 0.05). Hepatosomatic index(HSI) and viscerosomatic index(VSI) showed slightly increase with the increasing of dietary lipid level. The concent of plasma triglyceride(TG) and total cholesterol(T–CHO) increased slightly with the increasing of dietary lipid level. The activities of ALT and AST raised as the dietary lipid level increase, and the group fed 14.04 % lipid diet showed significantly highest value. The content of moisture in the whole body decreased significantly with increasing dietary lipid level(P < 0.05). The whole body crude lipid content is the exact opposite. The crude protein and ash of the whole body and dorsal muscle seemed to keep at constant levels between diets(P > 0.05). Second–order regression analysis showed that the appropriate dietary lipid requirement of juvenile Dabry’s sturgeon is on a scale of 9.99 % to 10.56 %.