Effect Of Dietary Sanguinarine On Growth,Immunity And Intestinal Health Status Of Grass Carp(Ctenopharyngodon Idella)

A 8-week feeding experiment was conducted to investigated the effects of sanguinarine on the growth performance,immunity,and intestinal health of grass carp(initial weight,91.04±0.37g).the fish meal feed with 5%fish meal and 30%crude protein was set as the control group,and high cottonseed and rapeseed diet(2%fish meal,30%crude protein,HCR group)and low-protein basal diet(4%fish meal,28%crude protein,LPB group)were two consistent low-cost basal feeds.Base on two low-cost basal feeds,0,200,400,and 800mg/Kg of 0.15%sanguinarine were further added to the feed,and finally 9 different feeds were used in this study.The experiment was implemented in the cage which the size was 2×2×2 m,and located in Che tian jiang reservoir.The grass carp were randomly distributed into 9 groups,each group had 3 replicates and each replicate had 25 fish in this experiment.The experimental results are as follows:1.Growth,digestive enzyme activity and muscle textureCompared with the control group,no significant difference was observed in the growth performance in HCR group,but a decreased tendency was found in the Survival rate(SR)of grass carp fed diet with the increase of sanguinarine level,concurrent with a trend of increase in the SR and the Weight gain rate(WRG)and the maximum value in the800mg/Kg group.Compared with the 0mg/Kg group,a significant reduction was observed in total cholesterol(T-CHO)and blood in 800mg/Kg group,in which the activities of Na~+K~+-ATPase and Creatine kinase(CK)significantly increased;0mg/Kg group had a significantly higher muscle stiffness and adhesiveness,and the chewiness,while 400 and 800mg/Kg sanguinarine could decrease the above-mentioned indexes.Compared with the control group,though a reduction in WGR and SR was observed in 0mg/Kg LPB group,no significant difference was found between two groups;SR showed an increasing trend with the increase of sanguinarum level.Compared with the 0 mg/Kg group,the GLU,TG,and CK levels in the 800 mg/Kg group were significantly increased,but did not significantly differ from that in the control group;Na~+K~+-ATP was significantly higher than that in the control group.The experimental results showed that the addition of sanguinarum in HCR and LPB diets could improved the growth performance and digestibility of grass carp,and the best growth performance was found in 800 mg/Kg in the feed of HCR.2.Immune and intestine related gene expressionCompared with the control group,grass carp at 0 mg/Kg HCR group significantly reduced intestinal Superoxide dismutase(SOD)activity,increased Malonaldehyde(MDA)content,and added 800 mg/Kg of sanguinarine significantly increased complement-C3content and SOD activity,and decreased MDA content.Further study found that,compared with the control group,the 0mg/Kg HCR group significantly had the down-regulated gene expression of MnSOD,IL-1,TLR-4,TLR-8,Clandin,occludin and ZO-2 in the intestine;800mg/Kg of sanguinarine significantly increased MnSOD,IL-1,occludin gene expression levels,and the difference was not significant,down Keep1,Nrf-2,IL-6,TNF-?gene expression levels.Compared with the control group,SOD,Catalase(CAT),Glutathione peroxidase(GSH-PX)activity,and Glutathione(GSH)content were significantly reduced in the 0 mg/Kg LPB group,and SOD was significantly increased when 800 mg/Kg sanguinisine was added,and there was no significant difference from the control group.3.Intestinal structure and intestinal microbial diversityThe addition of sanguinarine into both HCR and LPB diets caused a higher villi height and/or crypt depth(V/C value)proximal intestinal and mid intestinal,and improved the mucosal structure of the intestine.Then,histological observation found that adding sanguinarine in HCR and LPB leave the intestine damaged.The content of intestinal contents was analyzed based on 16sRNA analysis of intestinal microbial community composition.Compared with the control group,the 0mg/Kg HCR group significantly reduced the Shannon index and the number of OTUs.The addition of 800mg/Kg sanguinisine resulted in significant OUTs reduce.At the genus level,Cetobacterium,Bacteroides,and Aeromonas constitute the dominant microbial genus,0mg/Kg of HCR group extract significantly increased the abundance of Cetobacterium and Aeromonas,but not in 800mg/Kg group.The abundance of Bacteroides significantly decreased the abundance of Aeromonas significantly increased after addition of 800 mg/Kg sanguinarine,and tended to change the intestinal microbial community structure in the control group.Conclusion:Sanguinarine has the tendency of improving the growth performance of grass carp.The addition effect of HCR diet is better than that of LPB diet,and it can improve digestion and absorption,enhance the immunity and antioxidation ability,and improve the intestinal structure function and intestinal microbial community structure.