Comparison of nitrogen transformation dynamics in non-irradiated and irradiated alfalfa and red clover during ensiling

Zhihao Dong,Junfeng Li,Lei Chen,Xianjun Yuan,Tao Shao 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.10

Objective: To study the contribution of plant enzyme and microbial activities on protein degradation in silage, this study evaluated the nitrogen transformation dynamics during ensiling of non- and irradiated alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.). Methods: Alfalfa and red clover silages were prepared and equally divided into two groups. One group was exposed to γ-irradiation at a recommended dosage (25 Gky). Therefore, four types of silages were produced: i) non-irradiated alfalfa silage; ii) irradiated alfalfa silage; iii) non-irradiated red clover silage; and iv) irradiated red clover silage. These silages were opened for fermentation quality and nitrogen components analyses after 1, 4, 8, and 30 days, respectively. Results: The γ-irradiation successfully suppressed microbial activity, indicated by high pH and no apparent increases in fermentation end products in irradiated silages. All nitrogen components, except for peptide-N, increased throughout the ensiling process. Proteolysis less occurred in red clover silages compared with alfalfa silages, indicated by smaller (p<0.05) increment in peptide-N and free amino acid N (FAA-N) during early stage of ensiling. The γ-irradiation treatment increased (p<0.05) peptide-N and FAA-N in alfalfa silage at day 1, whereas not in red clover silage; these two nitrogen components were higher (p<0.05) between day 4 and day 30 in non-irradiated silages than the irradiated silages. The ammonia nitrogen and non-protein nitrogen were highest in non-irradiated alfalfa silage and lowest in irradiated red clover silage after ensiling. Conclusion: The result of this study indicate that red clover and alfalfa are two forages varying in their nitrogen transformation patterns, especially during early stages of ensiling. Microbial activity plays a certain role in the proteolysis and seems little affected by the presence of polyphenol oxidase in red clover compared with alfalfaa.

Effects of calcium propionate on the fermentation quality and aerobic stability of alfalfa silage

Dong, Zhihao,Yuan, Xianjun,Wen, Aiyou,Desta, Seare T.,Shao, Tao Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.9

Objective: To assess the potency of calcium propionate (CAP) used as silage additive, an experiment was carried out to evaluate the effect of CAP on the nitrogen transformation, fermentation quality and aerobic stability of alfalfa silages. Methods: Alfalfa was ensiled with four levels of CAP (5, 10, 15, and 20 g/kg of fresh weight [FW]) in laboratory silos for 30 days. After opening, the silages were analyzed for the chemical and microbiological characteristics, and subjected to an aerobic stability test. Results: The increasing proportion of CAP did not affect pH, lactic acid (LA) concentrations and yeast counts, while linearly decreased counts of enterobacteria (p = 0.029), molds (p<0.001) and clostridia (p<0.001), and concentrations of acetic acid (p<0.001), propionic acid (p<0.001), butyric acid (p<0.001), and ethanol (p = 0.007), and quadratically (p = 0.001) increased lactic acid bacteria counts. With increasing the proportion of CAP, the dry matter (DM) loss (p<0.001), free amino acid N (p<0.001), ammonia N (p = 0.004), and non-protein N (p<0.001) contents were linearly reduced, whereas DM (p = 0.048), water soluble carbohydrate (p<0.001) and peptide N (p<0.001) contents were linearly increased. The highest Flieg's point was found in CAP10 (75.9), represented the best fermentation quality. All silages treated with CAP improved aerobic stability as indicated by increased stable hours compared with control. Conclusion: The addition of CAP can suppress the undesirable microorganisms during ensiling and exposure to air, thereby improving the fermentation quality and aerobic stability as well as retarding the proteolysis of alfalfa silage. It is suggested that CAP used as an additive is recommended at a level of 10 g/kg FW.

Remaining useful life prediction of circuit breaker operating mechanisms based on wavelet‑enhanced dual‑tree residual networks

Tailong Wu,Yuan Yao,Zhihao Li,Binqiang Chen,Yue Wu,Weifang Sun 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.1

The remaining useful life prediction of circuit breaker operating mechanisms is crucial for the condition-based maintenance of national power grids. To realize accurate remaining useful life prediction, a novel wavelet-enhanced dual-tree residual network is proposed in this paper. Through this wavelet transform, the time series is decomposed into two components (high frequency and low frequency). Then the two decomposed components are fed into two lightweight residual neural network structures. By concatenating the dual-tree features, the remaining useful life of a circuit breaker operating mechanism can be predicted. The proposed network is validated using a full-life cycle experiment of the circuit breaker operating mechanism. Results show that the proposed method has good capability when it comes to predicting the remaining useful life of the circuit breaker operating mechanism. Along with application in the construction of smart grids and green energy, it is expected that the proposed method has potential in running state prognostics of circuit breakers.

Characteristics of isolated lactic acid bacteria and their effects on the silage quality

Siran Wang,Xianjun Yuan,Zhihao Dong,Junfeng Li,Gang Guo,Yunfeng Bai,Junyu Zhang,Tao Shao 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.6

Objective: Four lactic acid bacteria (LAB) strains isolated from common vetch, tall fescue and perennial ryegrass on the Tibetan Plateau were characterized, and their effects on the fermentation quality of Italian ryegrass (Lolium multiflorum Lam.) silage were studied. Methods: The four isolated strains and one commercial inoculant (G, Lactobacillus plantarum MTD-1) were evaluated using the acid production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. The five LAB strains were added to Italian ryegrass for ensiling at three different temperatures (10°C, 15°C, and 25°C). Results: All isolated strains (LCG3, LTG7, I5, and LI3) could grow at 5°C to 20°C, pH 3.0 to 8.0 and NaCl (3.0%, 6.5%). Strains LCG3, LTG7, I5, and LI3 were identified as Lactobacillus plantarum, Pediococcus acidilactici, Lactobacillus paraplantarum, and Lactobacillus casei by sequencing 16S rDNA, respectively. All LAB inoculants significantly (p<0.05) increased lactic acid (LA) contents and ratios of lactic acid to acetic acid, and reduced pH and ammonia nitrogen/ total nitrogen (AN/TN) compared with uninoculated silages at various temperatures (10°C, 15°C, and 25°C). Compared to the commercial inoculant G, I5, and LI3 showed similar effects on improving the silage quality of Italian ryegrass at 10°C and 15°C, indicated by similar pH, LA content and AN/TN. Conclusion: All inoculants could improve the silage fermentation quality at various temperatures (10°C, 15°C, and 25°C). At the temperature of 10°C and 15°C, strain I5 and LI3 had similar effects with the commercial inoculant G on improving the silage quality of Italian ryegrass.

The enhanced electrical transport properties of Fe3+ doped Cu2SnS3

Lei Cao,Xueli Du,Xiaohui Guo,Zhihao Yuan 대한금속·재료학회 2021 ELECTRONIC MATERIALS LETTERS Vol.17 No.6

Cu 2 SnS 3 has attracted much attention as a promising environmental-friendly thermoelectric material. In this work, theFe 3+ doped Cu 2 Sn 1- x Fe x S 3 ( x = 0–0.2) compounds were prepared by a facile route of solvothermal synthesis and microwavesintering. Due to the shallow impurity energy level and additional energy states introduced by the d-unfi lled electrons inthe valence band, Fe 3+ doping eff ectively enhanced the electrical transport properties of Cu 2 SnS 3 , and the ultra-high powerfactor of 1.11 mWK −2 m −1 at 700 K is obtained from Cu 2 Sn 0.85 Fe 0.15 S 3 . Although the smaller grain size and the residualpores of the samples prepared by hydrothermal synthesis and microwave sintering effi ciently inhibited the increase of thelattice thermal conductivity, the improvement of electrical transport leads to the increase of electronic thermal conductivityand total thermal conductivity. Therefore, the fi nal result is not satisfactory, and the maximum ZT value is only 0.63, whichis obtained from Cu 2 Sn 0.85 Fe 0.15 S 3 at 700 K.