Research Of Carbohydrate And Lipid Metabolism In Muscles And Liver In Barbodes Schwanenfeldi During Exercise Training

Swimming, an important aspect of the lives in most teleost fish species, is closely related to important biological processes such as growth, early development, reproduction, feeding and escape. Fish show a great variety of swimming behaviors and strategies in different physiological and environment conditions. From a physiological point of view, fish can make rapidly response to the changed of swimming intensity, which the most direct response is material metabolism and energy supply in the organism. Moreover, the sources and levels of lipid in feed also have a profound effect on the material and energy metabolism in fish. In order to investigate the characteristics of carbohydrate and lipid metabolism in muscles and liver of fish, as well as the interactive effect of dietary lipid levels and training intensities on carbohydrate and lipid metabolism, two experiments were conducted in present thesis. And Barbodes schwanenfeldi was chosed as the experimental subject. The results had contributed to the understanding of metabolism characteristics in fish under swimming training, and provided the theoretic foundation for flowing water cultivates of fish. 1. The characteristics of carbohydrate and lipid metabolism in the muscles and liver in B. schwanenfeldi undering exercise trainingThree experimental groups were included based on swimming training intensities. Control group swimming with velocity of 0.0bl s-1, low intensity training group swimming with velocity of 1.0bl s-1, and high intensity training group swimming with velocity of 2.0bl s-1 during the training sessions. The experiment was conducted over 4 weeks and training time was 20 h in every day. The fish were fed to satisfaction twice daily. The effect of training on growth, body compositions, and the metabolism of carbohydrate and lipid in muscle and liver were investigated, which results as follows.The training have the positive effect to body growth(P>0.05), and the crude protein contents of muscles and liver were significanly increased with increasing training intensities(P<0.05), but the crude lipid contents in muscles were all significantly decreased in 2.0bl s-1 group compared with that in control group(P<0.05). The training have no significant effect on glycolysis in red muscle, but an opposite result was observed in white muscle which the glycogen content was significantly decreased but HK and PK activities were all significantly increased with increasing training intensities(P<0.05). The lipolysis in red muscle was significantly improved by swimming training, which the activities of key enzymes in lipolysis as HSL, CACT-I, HOAD and COX were all significantly increased with increasing training intensities(P<0.05). However, the lipolysis in white muscle was significantly restrained by swimming training. The glycogen content in liver was significantly decreased with increasing training intensities(P<0.05), but the opposite results were observed in the concentrations of TG and FFAs in plasma(P<0.05), which means the liver played an important role to maintain blood glucose levels. And the absorption and transportation of lipid in fish body by blood was also improved by swimming training.Swimming training also can affect markedly on the percentage composision of fatty aicds in muscles and liver. In the red muscle, the percentage of ?saturates was significantly decerased with increasing training intensity(P<0.05), but the opposite results were observed in the ?monoenes and ?PUFA(P<0.05). In the white muscle, the percentage of ?saturates had no significant difference among groups, however, the ?monoenes was significantly decreased in 2.0bl s-1 group and an opposite result was existed in ?PUFA(P<0.05). The percentage of ?monoenes in the liver was significantly increased in training groups, but the ?saturates in abdominal muscle in 2.0bl s-1 group was significantly lower than that in control group(P<0.05). However, the ?PUFA in abdominal muscle was significantly increased in 2.0bl s-1 group compared with that in control group(P<0.05). The results suggested that the saturated fatty acids in red muscle but monounsaturated fatty acids in white muscle were used priority as energy substances, and the saturated fatty acids in abdomal muscle likely transferred to active tissues as energy substances. 2. Effects of dietary lipid levels and swimming training on the metabolism of carbohydrate and lipid in B. schwanenfeldiTwo experimental factors, dietary lipid levels and training intensities, were included in the trial. Four diets were made on the basis of the lipid levels: D1, 6.29%; D2, 8.74%; D3, 11.19% VI and D4, 13.64%, respectively. And three training intensities were included: control group, 0.0bl s-1; low intensity group, 1.0bl s-1, and high intensity group, 2.0bl s-1. The experiment was conducted over 8 weeks and training time was 20 h in every day. The fish were fed to satisfaction twice daily(09:00 and 18:00 hours) with the experimental diets. Effects of dietary lipid levels and training intensities on the metabolism of carbohydrate and lipid, as well as the interaction between the two factors, were investigated. Which results as follows.The growth and CF of fish had not been affected by the dietary lipid levels and training, but the HSI was significantly decreased with increasing dietary lipid levels and training intensities(P<0.05). A decreased of crude protein contents but significantly increased(P<0.05) of crude lipid contents in muscles were observed in high dietary lipid level, however, the contents of crude protein and lipid in liver were all improved by high dietary lipid level(P>0.05). Moreover, the crude protein contents in muscles and liver were improved by training, but the opposite results were existed in crude lipid contents. Furthermore, the glycogen content in white muscle was significantly decreased with increasing dietary lipid levels(P<0.05). The glycolysis in muscles were depressed by high dietary lipid levels, which the HK and PK activities were all significantly decreased with increasing lipid levels in dietary(P<0.05). On the contrary, an significantly increased of HK and PK activities in muscles were observed in training groups(P<0.05). ACS and ACD are the key enzymes in lipolysis, the lipolysis in white muscle was stimulated by increased dietary lipid levels but opposite result existed in red muscle, which the ACD activity in white muscle was significantly increased with increasing dietary lipid levels but ACD and ACS activities in red muscle were all significantly decreased in high lipid level groups(P<0.05). Conversely, the lipolysis was decreased in white muscle but improved in red muscle under swimming training(P<0.05). The two factors, dietary lipid levels and training intensities, have a significantly interaction to glycolysis and lipolysis in muscles(P<0.05).The glycogen content in liver was significantly decreased with increasing both lipid levels in diet and training intensities(P<0.05), and the HK and PK activities were significantly increased in D4 but decreased in 1.0bl s-1 group(P<0.05). The results suggested that the glycolysis in liver was improved by high lipid levels in diet but depressed by training. The activities of GS and GP were all significantly decreased with increasing lipid levels and training intensities(P<0.05). The ACD activity in liver was markedly increased in group D4 but significantly decreased in 1.0 bl s-1 group(P<0.05), suggested that the lipolysis in liver was improved by high dietary lipid level but depressed by training. Moreover, the synthesis of fatty aicds in liver were all depressed by high dietary lipid level and training, which the FAS activity was significantly decreased with increasing both lipid levels in diet and traing intensities(P<0.05). The activities of LPL, HL and GE in liver were all significantly decreased with increasing lipid levels in diet(P<0.05), suggested that more lipid in blood was absorbed by liver. However, the increased activities of them was observed in 1.0 bl s-1 group, inferred that swimming training can reduce the lipid absorption from blood to liver. Furthermore, the ADA and GDH activities in liver were all significantly increased in D4 group but significantly decreased in training groups(P<0.05), suggested that swimming training had a positive effect on liver health but a negative effect was caused by high dietary lipid levels. The significantly interactions of dietary lipid levels and training intensities were also existed in carbohydrate and lipid metabolism in liver(P<0.05). With the observed by the light microscope, some of the liver cells in high dietary lipid level group had many fat droplets, showed characteristic vacuolation and the nucleus had been moved to the periphery of the cell. These symptoms are particularly associated with fatty liver, however, the swimming training in present study played an active role in promoting the liver health.