| With the continuous development of aquaculture industry,the use of antibiotics and pharmaceutical feed additives has resulted in the lack of high-quality feed,drug resistance in animals and drug residues in livestock and poultry products.It is particularly important to seek new high-quality feed raw materials and establish matching high-yield and high-quality cultivation techniques.Ramie stems and leaves are rich in nutrients,and have antioxidant,antibacterial,anti-inflammatory,anti-cancer and other effects,which can be used as high-quality feed materials.It can not only fill the feed gap in our country,alleviate the contradiction between human and livestock,but also enhance the immunity of livestock and poultry,reduce the addition of antibiotics,and promote the healthy development of animal husbandry.However,there was no systematic study on the high-yield and high-quality cultivation and harvesting technology for feeding ramie cultivation and the mechanism of ramie bacteriostasis and disease resistance.Hence,feeding potential of ramie cultivars were evaluated by production yield and feeding value and phenolic components,antioxidant activity as well as anti-inflammatory properties of leaf extracts were analyzed in this work.In addition,fertilization and harvest height were tested,and the effects of different cutting intensity on root molecular changes were studied by transcriptome.The main results are as follows:1.Screening of Ramie deeding resources and evaluation of feeding value of excellent germplasmsAccording to the crude protein content,47 high protein samples were selected from134 Ramie Germplasm resources.According to fresh grass yield,dry weight yield,crude protein yield and phosphorus content,47 high protein germplasm resources were analyzed by principal component analysis.Finally,Qianjiangxianma(QJX),Luzhuqing(LZQ),Lubandou(LBD),Douchanghema(DCH),Linshuizhuma(LSZ),Dazhuhuangbaima(DZB),Xingwenxiaoma(XWX),Libodadouma(LBM),and Dazhuhongma(DZH)were obtained with high feeding potential and compared with Zhongsizhu No.1(ZSZ).Rooting and propagation of stem-tip cuttings were carried out in greenhouse for 6 months and transplanted to the field.After growing in the field for 1 year,the comparative experiment of feed yield and quality was carried out.The results showed that the feed yield and quality of 4 varieties of Douchanghema,Dazhuhongma,Libodadouma and Dazhuhuangbaima were better than Zhongsizhu No.1.2.Analysis of phenolic components in Ramie leaves and evaluation of their biological activitiesThe phenolic constituents and antioxidant activities of alcohol extracts from leaves of 10 ramie varieties(9 selected excellent ramie feeding resources and Zhongsizhu No.1)were compared.The content of total phenolic compounds ranged from 0.52 to 2.41 mg/g dry weight,and the content of total flavonoids varied from 0.40 to 2.50 mg/g dry weight.The highest contents were found in cultivar Luzhuqing and the lowest levels were found in Libodadouma.UPLC-ESI-QTOF-MS analysis enabled to tentatively identify 15compounds in ten cultivars,mainly chlorogenic acid,rutin,p-coumaroylmalic acid,caffeoylmalic acid,feruloylquinic acid,hyperoside and isoquercetin.The highest contents of chlorogenic acid,rutin and p-coumaroylmalic acid were found in cultivar Luzhuqing with 439.49?g/g dry weight,339.97?g/g dry weight and 345.93?g/g DW,respectively.All cultivars performed differently on the antioxidant capacity and?-glucosidase inhibitory ability.Qianjiangxianma and Luzhuqing were the top two cultivars.The effects of ethanol extracts from Ramie leaves on NO production in RAW264.7mice cells were studied.The results showed that ethanol extracts from Ramie leaves had significant inhibitory effects on NO production in macrophages stimulated by LPS,and the inhibitory effects increased with the increase of ethanol extract concentration.3.Effects of fertilization and harvest height on forage yield and quality of RamieFour fertilization modes H:winter cultivation 1500 kg/hm~2 rapeseed cake fertilizer plus high chemical fertilizer(N 300 kg/hm~2,P 150 kg/hm~2,K 300 kg/hm~2);O:winter cultivation 1500 kg/hm~2 rapeseed cake fertilizer;L:low chemical fertilizer(N 150 kg/hm~2,P 75 kg/hm~2,K 150 kg/hm~2);CK:no fertilizer and six harvest heights(30 cm,40 cm,50cm,70 cm and 80 cm)were used to split plot test.Huazhu No.5(5-year-old)was studied for two continuity years and results showed that the optimum forage harvest height was50-70 cm,and the optimum fertilization mode was 1500 kg/hm~2 rapeseed cake fertilizer in winter with high chemical fertilizer(N 300 kg/hm~2,P 150 kg/hm~2,K 300 kg/hm~2).4.Study on molecular mechanisms of root response to cutting stress in Ramie by transcriptionomicsRNA was extracted from 30 cm(harvested 10 times)and 70 cm(harvested 8 times)ramie fleshyroot harvested 1 year later,and high-throughput transcriptome sequencing was carried out using Illumina HiSeq TM 2000 platform.448 differentially expressed genes were obtained,of which 282 were up-regulated and 166 were down-regulated.These differentially expressed genes mainly come from bHLH,EFR,Zinc finger,MYB,NAC and WRKY gene families.The soluble sugar content of ramie fleshyroot after harvesting for one year was analyzed.The results showed that the soluble sugar content in Ramie roots increased significantly with the increase of harvesting times.Five phenolic substances,chlorogenic acid,proanthocyanidin dimer,epicatechin,progeranidin dimer and proanthocyanidin trimer,were identified in Ramie fleshyroot by UPLC-ESI-QTOF-MS and the content of phenolic substances increased with the cutting times. |
PDF Full Text Request