Effect Of High Carbohydrate Levels In The Dietary On Growth Performance,Immunity And Hsp70of Carassius Auratus Gibelio

Allogynogenetic Crucian Carp bred by artificial insemination using of Carassius auratus gibelio Block as female parent which is natural gynogenetic and Cyprinus carpio var. singuonensis as male parent. It has become a major strain of carp in China with characteristics of growing fast, widely food habit, less disease and so on. In order to study the capability of utilizing carbohydrate in the diet and the effects of different carbohydrate diets on Allogynogenetic Crucian Carp, artificial purified feed with normal (including35%carbohydrate) and high (including50%carbohydrate) level carbohydrate were applied.168individuals of Allogynogenetic Crucian Carp (35.60±1.11g) were divided into the two carbohydrate level groups, and each group has three replicates which were cultured in aquarium with automatic temperature control culturing system with recycling water for10weeks. After that, indicators of fish growth, hepatosomatic, liver pyruvate kinase activities, plasma biochemical indices, immune indicators, plasma insulin and cortisol levels and HSP70expression levels in liver, heart, spleen and kidney were measured.1. Effect of high carbohydrate level diets on the growth, dry matter apparent digestibility, blood parameters and hepatic glycogen of Allogynogenetic Crucian Carp.Fed with different carbohydrate level diets for70days, the fish weight of each cylinder was statisticed and calculated, such as weight gain rate, specific growth rate, feed conversion rates. The results showed the specific growth rate, weight gain rate and protein utilization efficiency were significantly higher than normal carbohydrate group(35%CHO), but no significant difference between normal carbohydrate group(35%CHO) and high carbohydrate group(50%CHO)on feeding rate, feed conversion rates, muscle composition, hepatosomatic indices, gonad indices and fullness coefficient. It indicated50%level digestible carbohydrate of diet might inhibit the growth.During the process of fed different carbohydrate diets, there was a lower trend on total plasma protein of35%CHO group and a trend of decreasing on50%CHO group. The plasma triglycerides and total cholesterol of35%CHO group and50%CHO group presented a trend of increase first and then decrease. Compared with35%CHO group, the total plasma protein, triglycerides and cholesterol content of50%CHO group didn’t significantly change(P>0.05). It indicated50%carbohydrate level in feed didn’t affect plasma total protein, triglyceride and total cholesterol levels of Allogynogenetic Crucian Carp.Fed with different carbohydrate level diets, blood glucose and hepatic glycogen content had a significant upward trend on35%CHO group and50%CHO group. Compared with35%CHO group, hepatic glycogen content of50%CHO group was significantly (P<0.05) lower on35d. This shows that35%and50%carbohydrate levels in diet obviously prompted the blood glucose and hepatic glycogen content increased.2. Effect of high carbohydrate levels diets on plasma insulin, lactate and hepatic pyruvic acid, pyruvate kinase activities of Allogynogenetic Crucian CarpDuring the process of fed different carbohydrate diets,35%CHO group and50%CHO group presented an up trend on plasma insulin level and hepatic pyruvate kinase activity. On70d, plasmas insulin content of50%CHO group was significantly(P<0.05) lower than35%CHO group, while PK activity of50%CHO group higher than35%CHO group on70d.lt indicated plasma insulin content increased with carbohydrate level increased because of the effect of glycolysis strengthened and accelerated to transform the excessive carbohydrate.During the process of fed different carbohydrate diets, hepatic pyruvic acid content of the two groups increased first and then decreased, and there was no significant differences between35%CHO group and50%CHO group on35d and70d(P>0.05). The changes were not same with pyruvate kinase activity, which indicated pyruvate kinase is a key rate-limiting enzyme for hepatic pyruvic acid synthesis. Maybe there were many other rate-limiting reactions during this glycolysis process. With these interactions of multiple factors, pyruvic acid presented such a phenomenon.During the process of fed different carbohydrate diet, the plasma lactate of35%CHO group and50%CHO group sustained decreased. Compared with35%CHO group,50%CHO group lactate content was significantly (P<0.05) increased by32.93%. From the perspective of carbohydrate metabolism, these were almost the same with pyruvic acid and pyruvate kinase in the trend, which showed that it produced more pyruvic acid, consumed more oxygen and resulted more lactate of50%CHO group during the process of carbohydrate metabolism.3. Effect of high carbohydrate levels diet on plasma and hepatic immune parameters of Allogynogenetic Crucian CarpDuring the process of fed different carbohydrate diets, the hepatic MDA content of35%CHO group presented a trend of increase first and then decrease, and50%CHO group had a up trend. The50%CHO group was significantly (P<0.05) higher than35%CHO group on hepatic MDA content on70d. The hepatic SOD, T-AOC, ALT, AST and AKP content of35%CHO group and50%CHO group presented a trend of decreasing. The hepatic AST content was significantly lower than35%CHO group (P<0.05) on70d.35%CHO group performed rising with time goes on the lysozyme concentration, while50%group rised after decreased slightly. On30d,70d, there was no significant(P>0.05) differences between35%CHO group and50%CHO group. This shows that50%carbohydrate level of diet may impact the immune system of Allogynogenetic Crucian Carp and is likely to cause negative stresses.4. Effect of high carbohydrate levels in diet on plasma cortisol hormones and HSP70gene expression levels of liver, kidney, heart and spleen of Allogynogenetic Crucian CarpDuring the process of fed different carbohydrate diets, the normal(35%CHO) group showed continuously increasing on plasma cortisol and the high(50%CHO) group decreased after rapid increased. On35d, the plasma cortisol levels was significantly higher than35%CHO group (P<0.05). From the result, we thought50%carbohydrate of diet may caused some stress to Allogynogenetic Crucian Carp.The relative expression levels of HSP70in liver, spleen, kidney and heart were measured by Real-time PCR. Fed with different carbohydrate diets, the HSP70expression levels in liver, spleen, kidney and heart of high (50%CHO) carbohydrate level dietary were all increased. And the HSP70expression levels in liver and spleen of50%CHO group was significantly (P<0.05) higher than35%CHO group. It meant that liver and spleen of fish were more sensitive to carbohydrate, and caused changes of the HSP70gene expression levels rapidly. In addition, the high carbohydrate level (50%CHO) of diet may caused stress to Allogynogenetic Crucian Carp.