Dynamic changes and characterization of the protein and carbohydrate fractions of native grass grown in Inner Mongolia during ensiling and the aerobic stage

Du, Zhumei,Risu, Na,Gentu, Ge,Jia, Yushan,Cai, Yimin Asian Australasian Association of Animal Productio 2020 Animal Bioscience Vol.33 No.4

Objective: To improve the utility of native grass resources as feed in China, we investigated the dynamics of protein and carbohydrate fractions among Inner Mongolian native grasses, during ensiling and the aerobic stage, using the Cornell Net Carbohydrate and Protein System. Methods: Silages were prepared without or with lactic acid bacteria (LAB) inoculant. We analyzed the protein and carbohydrate fractions and fermentation quality of silages at 0, 5, 15, 20, 30, and 60 d of ensiling, and the stability at 0.5, 2, 5, and 10 d during the aerobic stage. Results: Inner Mongolian native grass contained 10.8% crude protein (CP) and 3.6% water-soluble carbohydrates (WSC) on a dry matter basis. During ensiling, pH and CP and WSC content decreased (p<0.05), whereas lactic acid and ammonia nitrogen (N) content increased (p<0.05). Non-protein N (PA) content increased significantly, whereas rapidly degraded true protein (PB₁), intermediately degraded true protein (PB₂), total carbohydrate (CHO), sugars (CA), starch (CB₁), and degradable cell wall carbohydrate (CB₂) content decreased during ensiling (p<0.05). At 30 d of ensiling, control and LAB-treated silages were well preserved and had lower pH (<4.2) and ammonia-N content (<0.4 g/kg of fresh matter [FM]) and higher lactic acid content (>1.0% of FM). During the aerobic stage, CP, extract ether, WSC, lactic acid, acetic acid, PB₁, PB₂, true protein degraded slowly (PB₃), CHO, CA, CB₁, and CB₂ content decreased significantly in all silages, whereas pH, ammonia-N, PA, and bound true protein (PC) content increased significantly. Conclusion: Control and LAB-treated silages produced similar results in terms of fermentation quality, aerobic stability, and protein and carbohydrate fractions. Inner Mongolian native grass produced good silage, nutrients were preserved during ensiling and protein and carbohydrate losses largely occurred during the aerobic stage.

Influence of microbial additive on microbial populations, ensiling characteristics, and spoilage loss of delayed sealing silage of Napier grass

Cai Yimin,Du Zhumei,Yamasaki Seishi,Nguluve Damiao,Tinga Benedito,Macome Felicidade,Oya Tetsuji 아세아·태평양축산학회 2020 Animal Bioscience Vol.33 No.7

Objective: To measure whether a microbial additive could effectively improve the fermentation quality of delayed-sealing (DS) silage, we studied the effects of inoculants of lactic acid bacteria (LAB) and cellulase enzyme on microbial populations, ensiling characteristics, and spoilage loss of DS silage of Napier grass in Africa. Methods: Quick-sealing (QS) and DS silages were prepared with and without LAB (Lactobacillus plantarum) inoculant, cellulase enzymes, and their combination. The QS material was directly chopped and packed into a bunker silo. The DS material was packed into the silo with a delay of 24 h from harvest. Results: In the QS silage, LAB was dominant in the microbial population and produced large amounts of lactic acid. When the silage was treated with LAB and cellulase, the fermentation quality was improved. In the DS silage, aerobic bacteria and yeasts were the dominant microbes and all the silages were of poor quality. The yeast and mold counts in the DS silage were high, and they increased rapidly during aerobic exposure. As a result, the DS silages spoiled faster than the QS silages upon aerobic exposure. Conclusion: DS results in poor silage fermentation and aerobic deterioration. The microbial additive improved QS silage fermentation but was not effective for DS silage.

Community of natural lactic acid bacteria and silage fermentation of corn stover and sugarcane tops in Africa

Cai Yimin,Du Zhumei,Yamasaki Seishi,Nguluve Damiao,Tinga Benedito,Macome Felicidade,Oya Tetsuji 아세아·태평양축산학회 2020 Animal Bioscience Vol.33 No.8

Objective: To effectively utilize crop by-product resources to address the shortage of animal feed during the dry season in Africa, the community of natural lactic acid bacteria (LAB) of corn stover and sugarcane tops and fermentation characteristics of silage were studied in Mozambique. Methods: Corn stover and sugarcane tops were obtained from agricultural field in Mozambique. Silage was prepared with LAB inoculant and cellulase enzyme and their fermentation quality and microbial population were analyzed. Results: Aerobic bacteria were the dominant population with 107 colony-forming unit/g of fresh matter in both crops prior to ensiling, while 104 to 107 LAB became the dominant bacteria during ensiling. Lactobacillus plantarum was more than 76.30% of total isolates which dominated silage fermentation in the LAB-treated sugarcane top silages or all corn stover silages. Fresh corn stover and sugarcane tops contain 65.05% to 76.10% neutral detergent fiber (NDF) and 6.52% to 6.77% crude protein (CP) on a dry matter basis, and these nutrients did not change greatly during ensiling. Corn stover exhibits higher LAB counts and water-soluble carbohydrates content than sugarcane top, which are naturally suited for ensiling. Meanwhile, sugarcane tops require LAB or cellulase additives for high quality of silage making. Conclusion: This study confirms that both crop by-products contain certain nutrients of CP and NDF that could be well-preserved in silage, and that they are potential roughage resources that could cover livestock feed shortages during the dry season in Africa.

Tuning the Mechanical Properties of Silkworm Silk Fibres by Thermally Induced Modification of Crystalline Nanostructure

Shan Du,Weitao Zhou,Xing Jin,Yimin Zhang,Xiangxiang Chen,Jin Zhang,Jingliang Li,Xungai Wang 한국섬유공학회 2021 Fibers and polymers Vol.22 No.2

Antheraea pernyi and Bombyx mori silk fibres, the most important and the subjects of several studies, have attractedwidespread attention due to their exceptional mechanical properties and promising applications. However, the determinantsbehind the variations of mechanical property between these two fibres still remains unknown. In this paper, the nanocrystallinestructures of these two silk fibres were tuned by thermal treatment in order to understand how the structure affects themechanical properties of fibres. It has been found that, along with an increase in temperature for thermal treatment, theincrease in the intramolecular β-sheet leads to progressive increase in longitudinal modulus and radial hardness, whilst thereduction in crystallinity results in great reduction in breaking tensile strength. The yield strength is proportional to theaverage crystallite size which increases along with the annealing temperature. Compared to B. mori, A. pernyi silk fibres havemore obvious temperature-dependant structural changes. These findings explain how size effects can be exploited to createbioinspired materials with tuneable mechanical properties.

Research on Vibration Characteristics of Spur Gear System with Pitting Fault Considering the Elastohydrodynamic Lubrication Condition

Chunlong Deng,Yimin Shao,Hongling Zheng,Minggang Du,Yang Yang 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10

Pitting fault is easily observed in gear system, dynamics models are commonly established to study the vibration characteristics affected by pitting fault. However, most of the dynamics models ignore the elastohydrodynamic lubrication (EHL) in gear system, which plays an important role in early fatigue failure of gears. Therefore, a dynamics model is proposed to study the vibration characteristics of spur gear system with pitting fault based on the three-dimensional line contact elastohydrodynamic lubrication (3D-EHL) model. In this model, both the transverse torsional dynamics model with gear pitting fault and the 3D-EHL model are coupled through an iterative method. Firstly, the transient rolling and sliding velocity, radius of curvature, and dynamic tooth force will be calculated based on the transverse torsional dynamics model, and which are then applied in the 3D-EHL model to perform contact analysis on a single continuously meshing teeth pair. Secondly, the transient pressure and film thickness distribution calculated based on the 3D-EHL model are used to determine the rolling, sliding friction, and viscous damping of the gear pair. After that, these parameters are substituted into the dynamics model to obtain the vibration characteristics of gear system with pitting fault. Finally, different working conditions are compared based on the proposed model, the results show that the EHL has an effect on the vibration characteristics of gear system with pitting fault.

Differences in the starvation-induced autophagy response in MDA-MB-231 and MCF-7 breast cancer cells

Wanyun Zhu,Hong-Jiang Wei,Hong-Ye Zhao,Hao Qu,Kaixiang Xu,Baoyu Jia,Haifeng Li,Yimin Du,Guangming Liu 한국통합생물학회 2017 Animal cells and systems Vol.21 No.3

Breast cancer is a heterogeneous disease with distinct subtypes that have made targeted therapy of breast cancer challenging. Previous studies have demonstrated that an altered autophagy capacity can influence the development of breast cancer. However, the molecular differences in starvationinduced autophagic responses in MDA-MB-231 and MCF-7 cells have not been fully elucidated. In this study, we found that an increase of LC3B-II protein expression level and a decrease of the p62 protein expression level in both cells treated by Earle’s balanced salt solution. Meanwhile, we observed an increase of autophagosome using transmission electron microscopy and an enhancement in the green fluorescence intensity of LC3B protein by confocal microscopy. Furthermore, we detected the expression of 13 autophagy-related (ATG) genes and 11 autophagy signaling pathway-related genes using qPCR. Among 13 ATG genes, we found that 6 genes were up-regulated in treated MDA-MB-231 cells, while 4 genes were up-regulated and 1 gene was down-regulated in treated MCF-7 cells. In addition, among 11 autophagy signaling pathway-related genes, 7 genes were up-regulated in treated MDA-MB-231 cells, while 5 genes were up-regulated and 1 gene was down-regulated in treated MCF-7 cells. These findings suggest that the autophagic response to starvation was different in the two treated cell lines, which will contribute to further study on the molecular mechanism of starvation-induced autophagy and improve the targeted therapy of breast cancer.