Effects Of Different Dietary Carbohydrate-to-lipid(CHO/L)ratio And Chromium-nicotinic On Growth Performance And Metabolism In Carp(cyprinus Carpio Jian)

1 The effect of different dietary CHO/L ratio level on growth performance,physiological and biochemical indexes of carpThe effect of different dietary CHO/L ratios(5.23,6.79,9.63,14.96,27.69)on the growth and nutritional condition of carp was determined in this study,by measuring standard growth parameters and physiological and biochemical indexes.Three replicate groups of 70 carp(initial weight 44.45±1.6)g per diet treatment were held in 15 cages(2m×1m×1m)at 30? for 63 days.The results showed that maximum WG,SGR and minimum FCR were observed in carp fed a CHO/L ratio of 6.79(P<0.05).With the increase of diary CHO/L ratio level,the crude lipid level of body and muscle at 5.23,27.69 level were significantly higher than other groups(P<0.05),and the ash content of muscle got the minimum at 14.96 level(P<0.05).While the other indexes of carp fed varying CHO/L diets did not show any discernible differences among the test groups(P>0.05).Dietary CHO/L ratio level remarkably affected the serum biochemical indexes and antioxidant capacity of carp(P<0.05).The maximum TG content and minimum T-Chol content were founded in 6.79 and 14.96 CHO/L level(P<0.05),respectively.GLU content increased with the increasing of diary CHO/L ratio(P<0.05).With the increasing of dietary CHO/L ratio level,the antioxidant capacity of carp first raised and then decreased.At dietary CHO/L ratio of 6.79,the activity of SOD in serum reached the highest level,which was significantly higher than that in fish fed diet with CHO/L ratio of 14.96 and 27.69.While the MDA content in serum and hepatopancreas got the minimum at 9.63 level.CAT activity in serum significantly decreased with the increasing dietary CHO/L ratio.At the same time,the GOT/GPT got the maximum at 27.69(P<0.05).The group fed with CHO/L ratio 6.79 showed a higher hepatopancreas and midgut protease activity.In terms of foregut protease activity diets 5.23,6.79,9.63,27.69 were not significantly different from one another but these diets were significantly better than diet 14.96(P<0.05),and there were no significant difference in hindgut(P>0.05).The hepatopancreas and foregut amylase activity reached the highest level in carp fed a CHO/L ratio of 14.96 level(P<0.05),while the midgut and hindgut amylase activity reduced with the increasing of diary CHO/L level.The lipase in all organizations showed a same trend,which raised first and then went down and got the highest level at 14.96 CHO/L level.Considered the growth,body composition,serum biochemical indexes and digestive enzymes activity,the optimal dietary CHO/L ratio of carp is 6.79~14.96.2 The effect of different dietary CHO/L ratio level on activity and m RNA expression of metabolic enzyme of carpMaterials and methods were the same as those in experiment 1.The result showed that organizations PK,HK,GK,G6 Pase,PEPCK activity first increased and then went down with the increase of dietary CHO/L ratio level.The highest serum PK activity was obsersed in fish fed diet at 9.63 CHO/L level,while the highest GK,G6 Pase and PEPCK activity were found in 6.79 CHO/L level.In hepatopancreas,the activity of PK,G6 Pase,PEPCK got maximum in 6.79 level,while the peak of GK activity was observed in 9.63 level.However,in kidney,the activity of PK,GK,G6 Pase and PEPCK got the maximum in fish fed diets with 6.79,27.69,9.63 and 9.63 dietary CHO/L level,respectively.The highest HK activity of the three organizations was found in group of 6.79 dietary CHO/L.In hepatopancreas,LPL and GE activity reduced and then raised with the increase of dietary CHO/L ratio level,and the highest LPL and GE activity were both observed in 5.23 level(P<0.05).LPL activity showed no significant difference between 5.23~14.96 level(P>0.05),but they were lower than that in 27.69 level(P<0.05),the activity of GE got the maximum in 27.69 level and got the minimum in 9.63 level(P<0.05),and other groups showed no significantly difference in kidney(P>0.05).In hepatopancreas,the activity of FAS raised firstly and then went down with the increase of dietary CHO/L ratio,and got the maximum in 6.79 level(P<0.05),while in kidney,FAS activity showed no significantly difference(P>0.05).After fasting and refeeding,hepatopancreas and kidney were taken to measure the m RNA expression of G6 Pase,PEPCK,PK,FAS,LPL,using semi-quantitative RT-PCR technology.The result showed that the PK m RNA expression raised and then went down,in hepatopancreas,PK m RNA expression got the maximum at 4h when the dietary CHO/L was between 14.96~27.69,and the others were in 6h,and in kidney,PK m RNA expression got the maximum at 6h when the dietary CHO/L was between 5.23~14.96,while the 27.69 level was in 4h(P<0.05).G6 Pase and PEPCK m RNA expression have a brief period of decline,and then raised to the maximum,in hepatopancreas,G6 Pase and PEPCK m RNA expression got the maximum at 4h when the dietary CHO/L was 5.23,and the others were in 6h;and in kidney,PK m RNA expression got the maximum at 4h when the dietary CHO/L was between 5.3~14.96,while the 27.69 level was in 6h(P<0.05).LPL m RNA expression raised first and then went down with the increase of dietary CHO/L ratio level.In Hepatopancreas,LPL m RNA expression got the maximum at 4h when the dietary CHO/L was between 9.63~14.96,and the others were in 6h(P<0.05).In kidney,LPL m RNA expression got the maximum at 4h when the dietary CHO/L was between 5.23~6.79,while the others was in 6h(P<0.05).After lasting and refeeding,FAS m RNA expression reduced and then increased with the increase of dietary CHO/L ratio level,and wich got the minimum at 6h when the dietary CHO/L was between 5.23~14.96(P<0.05).Considered the activity and m RNA expression of metabolic enzyme,high dietary CHO/L ratio can promote the activity of glycolytic,and inhibit the activity of gluconeogenesis,the optimal dietary CHO/L ratio of carp is 6.79~9.63.3 Effects of different dietary CHO/L ratio level on intestinal bacterial communities of carpIn this study,a PCR-denaturing gradient gel electrophoresis(DGGE)protocol was used to monitor the intestinal microbial communities of carp fed with different CHO/L ratio diets(5.23,6.79,9.63,14.96 and 27.69)for 30 or 60 days.Total microbial DNA were extracted directly from the intestinal and subjected to PCR and reverse transcription-PCR,and the amplicons obtained were analyzed by DGGE.The results showed that 17,21,18 OUTs were separated in foregut,midgut and hindgut of carp,respectively.Results demonstrated they were Proteobacteria,Firmicutes,Fusobacteria,Spirochaetes and Bacteroides.In conclusion,dietary CHO/L ratio can affect the types and quantities of carp intestinal flora,and Proteobacteria is the dominant bacteria,among them,Aeromonas,Pseudomonas,Acinetobacter and Bacteroides are the common intestinal bacteria.Considering the contribution of intestinal flora,the superiority flora were from Aeromonas and Pseudomonas.Although the results of this test can not accurately identify species and quantities,but can prove the relative change in intestinal flora of carp which were feed with different CHO/L dietary level diet,can provide support on the effect of bait on fish intestinal microflora,it has a certain theoretical guiding significance4 Effects of different dietary chromium-nicotinic levels on growth and related regulation mechanism of carpA 8-week experiment was conducted to evaluate the effects of dietary chromiumnicotinic on the growth and related regulation mechanism of carp.Fish(initial length 12.31±0.2 cm;initial weight 46.57±2.80 g)were stocked in triplicate tanks(40 fish per tank)and fed to satiation twice a day.Six diets were formulated by adding chromium-nicotinic at different levels of 0,1,2,4,8 and 16 mg/kg.Experiment results showed that chromium-nicotinic,especially 1 mg/kg chromium,could improve the WG,SGR and contidition factor in carp.And the FCR was also got the minimum at 1 mg/kg chromium level.Different chromium-nicotinate levels showed significant influence on serum indexes of carp.Serum T-Chol and TG content decreased significantly with the increasing dietary chromium ratio(P<0.05),and got the minmum at 1 mg/kg level;while the lowest Glu content was found in the 2 mg/kg level.At the same time,the lowest GOT,GPT activity and GOT/GPT were found in 1~2 mg/kg level(P>0.05).Organizations metabolic enzyme activity first increased and then went down with the increasing dietary chromium level.The highest serum PEPCK and G6 Pase activity were both obsersed in 1 mg/kg level,while the peak of HK activity was found in 2 mg/kg level(P<0.05).In hepatopancreas,the peak of HK and G6 Pase activity were found in fish fed diet with 1 mg/kg chromium-nicotinate,and GK activity got the maximum in 2 mg/kg level,PEPCK activity showed no significant difference between 1~8 mg/kg level,but they were higher than 0 and 16 mg/kg level(P<0.05).There were some difference in kidney,PEPCK activity signifiantly reduced in 4 mg/kg level(P<0.05)compared with other groups,while GK in 1 mg/kg level was significantly increased.G6 Pase and HK activity got the maximum at 2 mg/kg level(P<0.05).The peak of PK activity of the three organizations were found in 2 mg/kg level(P<0.05).Considering growth,serum indexes,immune ability and key metabolic enzyme activity,the suitable chromium level of carp is 1~2 mg/kg.