Study On The Utilization Of Dietary Carbohydrate By Mylopharyngodon Piecus Richardson And Carassius Auratus And Their Mechanism Of Metabolism

Fishes in general utilize dietary carbohydrate poorly, but the exact mechanism of the poor utilization of carbohydrate is still unclear. Mylopharyngodon piecus Richardson and Carassius auratus are two of widely cultured fishes in our country, the former is typical carnivorous and the latter typical omnivorous. There are fewer reports about the dietary carbohydrate utilization of these two fishes. This study was conducted to evaluate the ability of these two fishes to utilize dietary carbohydrate, and then to reveal the mechanism of carbohydrate metabolism in fish.1 The effects of dietary carbohydrate kind and level on growth and health offish1.1 The effects of dietary carbohydrate kind and level on growth and body composition of Mylopharyngodon piecus Richardson and Carassius auratusIsonitrogenous (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 piecus Richardson and 15 Carassius auratus respectively. The average initial weight was 2.14g and 6.75g respectively, and the feeding rate was about 4%. Animals were held in 100x50x60cm aquaria receiving recirculated water at 23.5 ?.5癈 (feeding trial 1). Weight gain ratio, feed efficiency ratio, protein efficiency ratio, protein and lipid retention efficiency, body composition, blood composition and hepatic index were measured to study their ability to utilize various kind and level dietary carbohydrate in order to obtain the basic data for study the mechanism of carbohydrate metabolism in fish. 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, or when fed with low dietary carbohydrate than high dietary carbohydrate, suggested two fishes utilize dextrin better than glucose, and lipid better than carbohydrate. Lipid content of body, hepatic and muscle and lipid retention efficiency of fishes fed diets containing dextrin was higher than those fed with glucose, indicated that dextrin was more potent to synthesize lipid than glucose. Glycogen increased with dietary carbohydrate level increased. Weight gain and feed efficiency of Mylopharyngodon piecus Richardson was higher than Carassius auratus, but Carassius auratus seem to have more powerful ability to maintain the inner equilibrium in the body than Mylopharyngodon piecus Richardson.1.2 The effects of dietary carbohydrate kind and level on antioxidant status,some non-specific immune parameter and tolerance of Cadmium by Mylopharyngodon piecus Richardson and Carassius auratusIt was known that weight gain and feed efficiency decreased with dietary carbohydrate increasing. This study was conducted to evaluate the effect of dietary carbohydrate kind and level on antioxidant status, some non-specific immune parameter and tolerance of Cadmium by Mylopharyngodon piecus Richardson and Carassius auratus. Mylopharyngodon piecus Richardson and Carassius auratus, whose initial weight were 1.63 +0.10g and 2.40 + 0.16g respectively, were fed on one of four isocaloric and isonitrogenous diets which formulated as feeding trial 1, overfeeding. Two commercial diets, with 60% crude protein and 3% carbohydrate, or 40% crude protein and 7% carbohydrate, were fed Mylopharyngodon piecus Richardson and Carassius auratus respectively as control (feeding trial 2). Tolerance of Cadmium was conducted after 8 weeks feeding trial and Spleen indices, glycosylated haemoglobin (Ghb), haemoglobin (Hb), erthrocyte osmotic fragility(Eof), superoxide dismutase (SOD), total antioxidant ability (T-AOC), alkaline phosphatase activity (AKP), haemolytic complement activity (CH50) and Lysozyme activity (Lys) were measured after 16 weeks. Spleen indices had no statistically significant difference among groups. The antioxidant status of fishes fed test diets increased significantly than those fed commercial diets, although high level of dietary carbohydrate resulted in descent slightly. The Hb and AKP of fishes fed die...