| 1.The effect of different concentrations dietary histamine on growth performance,immune response and intestinal health of grouper(Epinephelus coioides)was evaluated.630 juvenile fish(initial weight 29±0.52 g)were randomly divided into 7 groups(group T0,T1,T2,T3,T4,T5,T6)with 3 replicate per group and 30 fish per replicate.Basal diet was formulated with soybean meal,fish meal,fish oil and flour,and other six experimental diets were added with 0.5 g/kg,1 g/kg,1.5 g/kg,2 g/kg,2.5 g/kg,3 g/kg histamine,respectively.The fish were fed for 56 d.The results in the trial showed as follows:During the early period(day 0 to day 28),the weight gain rate(WGR),special growth ratio(SGR)and hepatosomatic index(HSI)of all experimental groups were lower than the control,but not significant statistically(P>0.05).The feed conversation ration(FCR)of all experimental groups were lower than the control,but not significant statistically(P>0.05).During the whole period(day 0 to day 56),the WGR and SGR of all experimental groups were lower than the control and groups T5 and T6 were lower significantly than the control(P<0.05).HSI of all experimental groups were lower than the control,but not significant statistically(P>0.05).The FCR of all experimental groups were higher than the control and group T6 increased significantly(P<0.05).Serum acid phosphatase(ACP),alkaline phosphatase(AKP),total antioxidant capacity(T-AOC),superoxide Dismutase(SOD)activities were lower significantly than the control at day 28(P<0.05).ACP,AKP and SOD activities of group T6 were lower significantly than the control and AKP,T-AOC,SOD activities of group T5 were lower significantly than the control at day 28(P<0.05).ACP,AKP,T-AOC and SOD activities were lower significantly than the control at day 56(P<0.05).AKP activity of group T5 was lower significantly than the control at day 56(P<0.05).Liver Malondialdehyde(MDA)levels of all experimental groups were higher than the control at day 28.Liver glutamic-oxaloacetic transaminase(GOT)and glutamic-pyruvic transaminase(GPT)activities of all experimental groups were lower than the control at day 28.MDA levels of group T6 and T5 were higher significantly than the control at day 28(P<0.05).GOT and GPT activities of group T6 were lower significantly than the control at day 28(P<0.05).MDA levels of all experimental groups was higher than the control at day 56.GOT and GPT activities of all experimental groups were lower than the control at day 56.MDA levels of group T5 and T6 was higher significantly than the control at day 56(P<0.05).GOT,GPT activities of group T6 was lower significantly than the control at day 56(P<0.05).Interleukin-1β(IL-1β),Serum amyloid A(SAA),C-reactive protein(CRP),Intestinal trefoil factor(ITF),Fatty acid-binding protein 2(FABP2)levels of all experimental groups were lower than the control at day 28.IL-1β、ITF、FABP2 levels of group T6 were higher significantly than the control and ITF、FABP2 levels of group T5 were higher significantly than the control at day 28(P<0.05).IL-1β,SAA,CRP,ITF and FABP2 levels of all experimental groups were higher than the control at day 56.IL-1β,ITF and FABP2 levels of group T6 were higher than the control at day 56(P<0.05).ITF level of group T5 was higher significantly than the control at day 56(P<0.05).The height of duplicature and the intestinal muscle thickness of all experimental groups were lower than the control at day 28.The height of duplicature and the intestinal muscle thickness of T5 and T6 were lower significantly than the control at day 28(P<0.05).The height of duplicature and the intestinal muscle thickness of all experimental groups were lower than the control at day 56.The height of duplicature and the intestinal muscle thickness of group T5 and T6 were lower significantly than the control at day 56(P<0.05).Intestinal microbiota results showed that relative abundance of Firmicutes decreased in groups T4,T5 and T6.At genus and phylum levels,the Beta similarity intestinal microbiota of groups T5 and T6 were different with group T0.In conclusion,the addition of 0.5-2.0 g/kg of dietary histamine did not affect growth performance,feed conversation ration and immune index,but the addition of 2.5～3.0 g/kg of dietary histamine could damage the intestinal health and immune response of the grouper and decreased growth performance and feed utilization efficiency.2.The previous study showed 2.5～3.0 g/kg of dietary histamine could damage the intestinal health and immune response of the grouper,and especially in the dose of 3.0 g/kg of dietary histamine.In this study,therefore,3.0 g/kg histamine was added in the diet as control.480 juvenile fish(initial weight 21±0.41 g)were randomly divided into 4 groups(group T1,T2,T3,T4)with 4 replicate per group and 30 fish per replicate.Basal diet was formulated with soybean meal,fish meal,fish oil and flour,and other six experimental diets were added with 1.0×108 cfu/g of Bucillus pumilus SE5,Psychrobacter sp.SE6 and B.claussi DE5,respectively.The fish were fed for 56 d.the results in the trial showed as follows:During the early period(day 0 to day 28),the WGR,SGR and HSI of all experimental groups were higher than the control,but not significant statistically(P>0.05).The FCR of all experimental groups were lower significantly than the control(P<0.05).During the whole period(day 0 to day 56),WGR,SGR and HSI of all experimental groups were higher than the control,but not significant statistically(P>0.05).The FCR of all experimental groups were lower than the control,but not significant statistically(P>0.05).ACP,AKP,T-AOC and SOD activities of all experimental groups were higher than the control at day 28 and day 56,but not significant statistically(P>0.05).MDA levels of group T5 and T6 was lower significantly than the control at day 28(P<0.05).MDA levels of all experimental groups was lower than the control at day 56,but not significant statistically(P>0.05).GOT and GPT activities of all experimental groups were higher than the control at day 28.GOT activities of group T2 and T4 was higher significantly than the control at day 28(P<0.05).GPT activities of group T2 was higher significantly than the control at day 28(P<0.05).GOT and GPT activities of all experimental groups were higher than the control at day 56,but not significant statistically(P>0.05).CRP and SAA levels of all experimental groups were lower than the control at day 28,but not significant statistically(P>0.05).IL-1β levels of all experimental groups were lower significantly than the control at day 28(P<0.05).FABP2 and ITF levels of group T2 and T3 were lower significantly than the control at day 28(P<0.05).CRP,SAA,FAPBP2 and ITF levels of all experimental groups were lower than the control at day 56,but not significant statistically(P>0.05).IL-1β levels of all experimental groups were lower significantly than the control at day 56(P<0.05).The height of duplicature and the intestinal muscle thickness of all experimental groups were higher than the control at day 28 and day 56,but not significant statistically(P>0.05).Intestinal microbiota results showed that the relative abundance of Firmicutes increased in group T4 and relative abundance of Vibrio decreased in group T3.At genus and phylum levels,the Beta similarity of T2,T3,T4 are similar to group T1.In conclusion,dietary supplemented with 2.5 g/kg and 3.0 g/kg histamine can deteriorated immune response and intestinal health of grouper,and decrease the growth performance and feed utilization.Probiotics could repair the intestinal damage induced by histamine,and improve the growth performance and immune response in grouper. |
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