| Berberine is an alkaloid extracted from Chinese herbal medicine(Coptis chinensis),which has many biological activities,such as antioxidant,antibacterial,lipid-lowering,etc.Berberine is mainly used in terrestrial animals to improve intestinal health and promote growth,and there are few reports on its application in aquatic animals.In this study,juvenile American eel(Anguilla rostrata)were fed with diets containing different levels of berberine,the growth performance and serum biochemical indices were examined,the expression of inflammatory cytokines,the intestinal histological morphology and changes in gut microbiome were studied to analysis the antiinflammatory function of berberine,and in combine with the intestinal metabonomics study to evaluate the supplemental effects of berberine and determine the suitable dosage.The results are as followed:1.Diets supplemented with 50 mg/kg-400 mg/kg berberine(termed BBR50 groups,BBR100 groups,BBR200 groups and BBR400 groups)significantly affected the final body weight,weight gain rate,specific growth rate and feed efficiency of American eels(P<0.05),and the BBR100 group was the most effective.Moisture,crude protein,crude lipid and crude ash contents were not significantly influenced by berberine supplementation(P>0.05).Serum biochemical indexes of berberine treatment groups were significantly different: Serum albumin,complement C3 and immunoglobulin M levels were significantly increased(P<0.05),and the highest value was observed in BBR100 group.There are no significant changes in activities of serum acid phosphatase and alkaline phosphatase(P>0.05)in all treatment groups except for BBR100 group.Urea nitrogen content,D-lactic acid level and diamine oxidase activity in BBR100 group decreased significantly(P<0.05).The activities of intestinal lipase and protease in BBR100 group were significantly increased(P<0.05),but there was no significant change in amylase(P>0.05).The level of total antioxidant capacity,the activities of total superoxide dismutase and glutathione peroxidase,the content of reduced glutathione were significantly increased in BBR100 group(P<0.05),but the level of malondialdehyde was significantly decreased(P<0.05).These results indicated that the supplementation of 100 mg/kg berberine in the diet can improve the immunity of juvenile American eel,enhance the abilities of intestinal digestion and absorption and antioxidant capacity,which can promote the growth of juvenile American eel.2.The expression of intestinal inflammatory factors have significant differences in berberine treatment groups.The transcription of TNF-α,IL-1B and IL-8 in BBR50,BBR100,BBR200 and BBR400 group were lower than those in control group,and the BBR100 group displayed the lowest expression level(P<0.05).The expression of IFN-γ in the four treatment groups was higher than that in the control group,and the BBR100 group displayed the highest expression level(P<0.05).The changes in intestinal histological structure were significantly different in treatment groups.The intestinal fold height,muscular thickness and number of goblet cells in BBR100 group were significantly higher than those in control group(P<0.05),and the intestinal microvilli were more densely packed together.The BBR100 and BBR400 group had obviously differences in the diversity of intestinal microflora.The Chao1 and ACE indexs of BBR100 and BBR400 groups were significantly decreased compared to the control group(P<0.05).The Shannon index of BBR100 group was significantly lower than that of control group(P<0.05),and there was no significant difference in Simpson index between BBR100 group and control group(P>0.05).At the phylum level,the core intestinal microflora were Tenericutes,Spirochaetae,Proteobacteria,Firmicutes and Bacteroidetes.At the genus level,the main bacteria genera were Novosphingobium,Azovibrio,Stenotrophomonas and Aeromonas.The relative abundances of four genera in the BBR100 group were significantly decreased compared to the control group and the BBR400 group(P<0.05).These findings indicated that to some extent,the supplementation of 100 mg/kg berberine in the diet could improve the intestinal health of American eel base on its anti-inflammatory function.3.Metabolomics analysis showed that 29 differential metabolites,mainly amino acids,fatty acids,organic acids,were filtered out from the intestinal tract samples of the BBR100 group.The expressions of 20 metabolites were up-regulated and 9 metabolites were down-regulated compared to the control group.These metabolites mainly belong to 9 metabolic pathways.Among the metabolites,L-glutamate and L-aspartic acid were the key factors,and L-glutamate participated in 5metabolic pathways,and L-aspartic acid participated in 4 metabolic pathways.These results indicated that the supplementation of 100 mg/kg berberine in the diet can promote the amino acids and protein metabolism in intestine.In conclusion,supplementation 100 mg/kg berberine can promote growth,induce anti-inflammatory and enhance the metabolic capacity,and then improve the intestinal health.Therefore,it can be considered that the suitable supplemental level of berberine in the diet for juvenile Anguilla rostrata is 100 mg/kg. |
PDF Full Text Request