| The Chinese Yam(Dioscorea opposita)is an important health food of the same origin as medicine and food in China.Because of its excellent quality,it is widely loved by the public.Chinese yam peel is the dander shaved during the processing of yam,which is mostly discarded as waste.Studies have shown that the main components of yam peel and yam are similar,and they also contain a large amount of active substances,which is a very promising resource.At present,the research on Chinese yam in livestock and poultry is very extensive,but as a feed additive in the field of aquaculture,there are relatively few studies,and the research on Chinese yam peel is rarely reported.The purpose of this test is to investigate the effects of Chinese yam and Chinese yam peel as feed additives on the growth,immunity,and intestinal flora of carps.To provide corresponding references for the development and application of Chinese yam-related products in the aquatic field,in order to improve the utilization of resources and increase economic benefit.In this work,375 carp with an average weight of 75.24 ± 1.32 g were selected and randomly divided into 5 groups,each group had 3 replicates,and each replicate had 25 fish.There were control group(NC group),1% Chinese yam peel addition(LYP group),2% Chinese yam peel addition(HYP group),1% Chinese yam extract addition(LCY group)and 2% Chinese yam extract addition(HCY group).After feeding for 8 weeks,the growth indexes,serum biochemical indexes,immune-related indexes,intestinal tissue morphology,intestinal enzyme activity,intestinal flora structure and diversity,short-chain fatty acid content of the experimental fish,and correlation analysis were measured.The experimental results are as follows:(1)Effect of Huai Chinese yam on growth performance and muscle components of common Carp(Cyprinus carpio)Compared with the NC group,the crude lipid content of the LYP group and the HYP group decreased(P < 0.05),while the effects of crude ash,crude protein,and moisture of carp muscle were not significant(P > 0.05);There was no statistical difference in FBW,WGR,SGR and FCR of the experimental group(P > 0.05),but WGR and SGR increased with the use of additives.Indicating that the addition of yam and yam peel has a certain growth-promoting effect on carp,but it is not obvious.(2)Improving effect of Chinese yam on common carp(Cyprinus carpio)immune functionCompared with the NC group,the serum alkaline phosphatase(ALP)concentration of each group was significantly reduced(P < 0.05).The concentrations of alanine aminotransferase(ALT)and aspartate aminotransferase(AST)in the HYP group were significantly reduced(P < 0.05).Based on the HE staining,the intestinal villi height of the HYP group and the LCY group was significantly increased compared with the NC group(P < 0.05).In addition,the intestinal villi integrity,muscle layer thickness,and number of goblet cells in the experimental group increased to a certain extent,but not significantly(P > 0.05).Scanning electron microscopy results showed that the number of intestinal mucosal folds in the experimental group was increased compared with the NC group,and it was more obvious in the HYP and HCY groups.In the head kidney,the expression level of gene IL-10 m RNA was significantly increased in the HCY group compared with NC group(P < 0.05),while the expression level of NF-κB was significantly increased in the HYP group(P < 0.05).In the hepatopancreas,gene IL-10 was significantly increased in the LYP group(P < 0.05),and TGF-β was significantly increased in the HCY group(P < 0.05).In the midgut,compared with the NC group,the expression level of gene IL-10 in the LCY group was significantly increased(P < 0.05),and the expression levels of IL-1β,TGF-β and TLR-4 genes were significantly increased(P < 0.01).In the HYP group,the expression levels of il-1,TGF-β,TLR-4,and NF-κB were significantly higher than that of the NC group(P < 0.05).TGF-β expression level significantly increased in LYP group(P < 0.05),while il-10 significantly increased in HCY group(P < 0.05).Compared with the NC group,the expression level of Occludin gene was significantly increased in the HYP group(P < 0.05),and significantly increased in the LYP and LCY groups(P < 0.01).Zo-1 was significantly increased in the LCY group(P < 0.05),indicating that yam and yam skin enhanced the protective effect of intestinal barrier.(3)Effects of Huai Chinese yam on intestinal microecology of carp(Cyprinus carpio)Compared with the NC group,the CAT and LZM activities of the LYP,HYP,LCY and HCY groups were significantly increased(P < 0.05),while SOD was significantly increased in the HYP,LCY and HCY groups(P < 0.05);MDA activity had no significant change compared with NC group(P > 0.05).(4)Effects of Chinese yam and Chinese yam peel on the intestinal flora structure and short chain fatty acids of carp(Cyprinus carpio)The contents of acetic acid,propionic acid and isobutyric acid in the 6 short chain fatty acids were significantly changed(P < 0.05).The contents of propionic acid and isobutyric acid were significantly higher in the HYP group than in the NC group Elevated(P < 0.05);acetic acid significantly increased in the LYP and HYP groups(P < 0.05),and also increased and extremely significant in the LCY and HCY groups(P < 0.01);the contents of short-chain fatty acids were significantly increased(P < 0.05).Different concentrations of Chinese yam and Chinese yam peel to the feed can change the community structure of the intestinal microbes of the carp and increase the diversity of the intestinal microorganism.At the gate level,compared with the control group,the abundance of Fusobacteria and Bacteroidetes in the experimental group increased significantly(P < 0.05),and the abundance of Proteobacteria and the ratio of Firmicutes/Bacteroidetes decreased(P < 0.05).At the genus level,the abundance of Cetobacterium increased while the number of conditional pathogens such as Aeromonas decreased.(4)Correlation analysisIn the analysis of the correlation between intestinal microorganisms and short-chain fatty acids,the flora represented by Proteobacteria,Bacteroidetes,and Fusobacteria had significant contents of intestinal short-chain fatty acids.Correlation;in the correlation analysis of intestinal microorganisms and intestinal immune genes,the immune gene IL-10 has a strong correlation with microbial abundance;in the correlation analysis of intestinal microorganisms and intestinal antioxidant enzyme activities,lysozyme(LZM)was significantly negatively correlated with Shewanella and Pseudomonas,while catalase(CAT)was related to Firmicutes,MDA,and There was a positive correlation between the abundance of Plesiomonas,superoxide dismutase(SOD)and Bacteroidetes.As a conclusion,the addition of Chinese yam and Chinese yam peel in the diet can enhance the immune performance of the carp,improve the intestinal flora,and have a certain protective effect on the physical barrier of the intestine,but it has no obvious effect on the growth performance and meat quality of the carp(Cyprinus carpio).It can be used as an immunostimulant in aquatic research. |
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