Advanced In The Study Of Utilization Of Carbohydrate By Black Carp (Mylopharyngodln Piceus Richardson)

There are two experiments conducted in this paper,the first experiment is about the effects of dietary carbohydrate kind and level on growth and body composition of Mylopharyngodon piceus,and the second experiment is about the response of antioxidant status,non-specific immunity and Cadmium tolerance to dietary carbohydrate in juveniles of black carp(Mylopharyngodln piceus Richardson ).Lab 1:Isonitrogenous(35%crude protein) and isocaloric(16.4KJ/g) diets containing 20%(L) or 40%(H) glucose(G) or dextrin(D) were fed 8 weeks to triplicate groups of 30 Mylopharyngodon piceus.The average initial weight was 2.14g. Weight gain ratio,feed efficiency ratio,protein efficiency ratio,protein and lipid retention efficiency,body composition were measured to study their ability to utilize various kind and level dietary carbohydrate.Fishes had significant better weight gain, feed and protein efficiency,and protein retention efficiency when fed the diets with dextrin than those fed with glucose,and when fed with low dietary carbohydrate than high dietary carbohydrate,suggested both fishes utilize dextrin better than glucose,and lipid better than carbohydrate.Fishes fed diets containing dextrin obtained not only higher lipid retention efficiency but also higher Lipid content of body,hepatic and muscle than those fed with glucose,which indicated that dextrin was more potent to synthesize lipid than glucose.Glycogen increased with increasing of dietary carbohydrate level.Lab 2:Four isonitrogenous(35%DM)and isocalorie(16.4 kJ g^-1 DM) diets with two types(dextrin and glucose) and two levels(20%and 40%respectively) of carbohydrates were each fed to three replicate tanks of black carp(Mylopharyngdon piceus Richardson) for 16 weeks to determine the antioxidant status and non-specific immunity.The initial body weight was 1.63±0.10g.Another group of black carp with initial body weigh 4.3±0.5g was tripartite fed the same diets for 8 weeks to analyze the livability 24h after Cadmium injected.No significant difference(p＞0.05) were observed among groups in weight gain rate,spleen indices and pancreatic indices.The GHb was higher in fish fed diet with high carbohydrate compare to that with low carbohydrate (p＜0.05).The pancreatic SOD,plasma SOD and plasma T-AOC in fish fed diet with glucose were higher than that with dextrin(p＜0.05),and the pancreatic T-AOC in fish fed diet with high carbohydrate was higher than that with low carbohydrate(p＜0.05).No significant difference was observed among groups in CH50 and Lysozyme(p＞0.05). The Erythrocyte Osmotic Fragility was lower in fish fed high carbohydrate diet than that fed low carbohydrate diet(p＜0.05).The livability after Cadmium injected didn't affected by diet(p＞0.05).These results indicated that the black carp can tolerate 40% dietary carbohydrate and carbohydrate can improved the antioxidant status.