Effects Of Aparagus Oligosaccharides And Algae Residue On The Physiological Characteristics Of Tilapia

Recent studies have showedthat oligosaccharides contain the active ingredients with antiviral,anti-tumor,anti-oxidation,immune-regulation,and other biological activities.In the field of medicine and functional food,oligosaccharides showthe great application prospect.Compared with other oligosaccharides,oligosaccharides derived from seaweed havenot been large-scale developed and utilized.Gracilaria lemaneiformis is the fourth largest cultivated algae of China,usually used to extract agar and abalone aquaculture.Agar residue is the main component of dietary fiber,there are almost no reports about the production of dietary fiber from waste residue in dietary fiber industry.The reports about the development and utilization of the agar residue are rarely and there areno relevant reports of patent.Agar residue has a great potential of development.Tilapia is an important freshwater aquaculture economic fishes andthe output occupies the second place of freshwater fish in the world.There is no exclusive high-quality fish feed for Tilapia currently.Through feeding Tilapia with the fish feed with asparagus oligosaccharide and algae residue,we can study the physiological characteristics of tilapia and so as to promote the application of Gracilaria lemaneiformis oligosaccharides and algae residue in fish feed.Asparagus was degraded by microbial enzyme to preparelemaneiformis oligosaccharides and algae residue,which wasincludedin fish feed.We add 0.1% asparagus oligosaccharide or 10% algae residue in the basic feed.The test groups were divided into three groups according to different feeds,namelycontrol group,oligosaccharide group and algal residue group.The experiment lasted for 7 months.First of all,we investigate the influence on the intestinal microbial diversity of Tilapia after adding asparagus oligosaccharides or algae residue feed.The intestinal flora of Tilapiawith different fish feeds was studied by Illumina high throughput sequencing technology,which obtained a lot of data,effective information and rich sequence results.We classified reads whose sequences shared more than 97% similarity into the same OTU and then we conducted OTU analysis,species annotation,alpha diversity and beta diversity analysis.The results showed that the intestinal flora of the three groups were all rich in diversity and the species and quantity of the intestinal flora were increased gradually from foregut to hindgut.The abundance regarding intestinal microflora community of oligosaccharide group was significantly higher than that in the other two groups,suggesting that Gracilaria lemaneiformis oligosaccharides may change the diversity of intestinal flora in a certain extent.The dominant bacteria in the three groups are Proteobacteria and Bacteroidetes,besides of these bacteria,oligosaccharide group and algal residue group has the dominant bacteria of TM7.The intestinal dominant flora control group,oligosaccharide group and algal residue group is overall similar and foregut and midgut of flora is more similar.Secondly,we study the influence on fatty acid of Tilapia after adding asparagus oligosaccharides or algae residue feed with GC-MS.We got 12 kinds of saturated fatty acids and 17 kinds of unsaturated fatty acids from control group,unsaturated fatty acids contained 8 kinds of unsaturated fatty acids and 9 kinds of polyunsaturated fatty acids.We got 6 kinds of saturated fatty acids and 15 kinds of unsaturated fatty acids,from oligosaccharide group,there were 7 kinds of unsaturated fatty acids and 8 kinds of polyunsaturated fatty acids.We got 7 kinds of saturated fatty acids and 15 kinds of unsaturated fatty acids,there were 7 kinds of unsaturated fatty acids and 8 kinds of polyunsaturated fatty acids.These results showed that the types of unsaturated fatty acids were similar in the three groups,but the amount of saturated fatty acids in the control group were about 2 times of the oligosaccharides group and algal residue group.As for the fatty acid content,additionof asparagus oligosaccharides or algal residue diet can significantly increase the Tilapia fatty acid ARA and relative contents of DHA / EPA ratio.Finally,we study the influence on fishy odor of Tilapia after adding asparagus oligosaccharides or algae residue feed with GC-MS.To get the relative content of chemical composition,we detected the volatile substances by data analysis using the software Excel 2007,quantitative analysis by using area normalization method,and peak identification by searching against the NIST05 standard fingerprint database.The control group had 31 kinds of volatile substances while oligosaccharides group and algal residue groups were 25.The types of volatile substance of control group are more than that of oligosaccharide group and algal residue group.In this experiment,the chemicals which have low threshold and high odor are halogenated alkanes,acids,amines and aldehydes.The relative content of these substances decreased in oligosaccharide group and algae residue group.These results showed that fishy odor of oligosaccharide group and algae residue group were lower than of control group and were consistent with the food sensory evaluation results.The results of the study showed that asparagus oligosaccharide and algae residue can increase the intestinal flora diversity of Tilapia,decrease the amount of saturated fatty acid of Tilapia,improve the ARA and relative contents of DHA/EPA ratio,reduce fishy odor,which maypromote the development of the potential of tilapia exclusive high quality feed.