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Stability and Micro-mechanisms of Lignin-improved Soil in a Drying-wetting Environment
Gaoqiang Wang,Xianghui Kong,Yanhao Zhang,Quanman Zhao,Xiao Feng 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8
To evaluate the long-term service performance of subgrade with high-liquid-limit soil improved by lignin, a drying-wetting cycle test was carried out for the improved soil with 3% lignin content, and comparison was made with quicklime-improved soil with the same properties in terms of pH, unconfined compressive strength (UCS), appearance, and volume stability. Using a scanning electron microscope (SEM), the microscopic characteristics of the lignin-improved soil were analyzed qualitatively and quantitatively. By analyzing the evolution law of the soil microstructure and pores under the action of drying-wetting cycles, the strength degradation mechanism of the improved soil was discussed at the microscopic level. The test results showed that the soil pH value of the lignin-improved soil was more beneficial to the ecological environment compared with that of the quicklime-improved soil. Furthermore, the stability of the lignin-improved soil was better than that of the quicklime-improved soil due to strength loss and increased volume expansion rate caused by the drying-wetting cycles. In terms of the microstructure, the cementing materials enhanced the agglomeration of the soil by wrapping grains and filling pores. Under the action of drying and wetting, the number of pores inside the soil increased, and the soil structure loosened. Under drying and wetting conditions, the strength degradation of the lignin-improved soil was the result of the interaction of pore development and cementing materials dissolution.
Song, Xiaozhen,Luo, Junrong,Fu, Daibo,Zhao, Xianghui,Bunlue, Kornmatitsuk,Xu, Zhensong,Qu, Mingren Asian Australasian Association of Animal Productio 2014 Animal Bioscience Vol.27 No.10
The present aim was to investigate the effects of traditional Chinese medicine prescriptions (TCM) on body temperature, blood physiological parameters, nutrient apparent digestibility and growth performance of beef cattle under heat stress conditions. Twenty-seven beef cattle were randomly divided into three groups as following; i) high temperature control (HTC), ii) traditional Chinese medicine prescriptions I+high temperature (TCM I) and iii) traditional Chinese medicine prescriptions II+high temperature (TCM II) (n = 9 per group). The results showed that the mean body temperature declined in TCM II treatment (p<0.05). Serum $T_3$ and $T_4$ levels with TCM I and TCM II treatments elevated (p<0.05), and serum cortisol levels of TCM I treatments decreased (p<0.05), compared with the HTC group. Total protein, albumin, globulin in TCM II treatments elevated and blood urea nitrogen levels of both TCM treatments increased, but glucose levels of both TCM treatments decreased, compared with the HTC group (p<0.05). The apparent digestibility of organic matter and crude protein with TCM I treatment increased, and the apparent digestibility of acid detergent fiber elevated in both TCM treatments (p<0.05). Average daily feed intake was not different among three groups, however average daily gain increased and the feed:gain ratio decreased with both TCM treatments, compared with the HTC group (p<0.05). The present results suggest that dietary supplementation with TCM I or TCM II improves growth performance of heat stressed beef cattle by relieving heat stress responses and increasing nutrient apparent digestibility.
Yang Zhuqing,Bao Linbin,Song Wanming,Zhao Xianghui,Liang Huan,Yu Mingjin,Qu Mingren 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.2
Objective: The aim of this study was to investigate the impact of dietary nicotinic acid (NA) on apparent nutrient digestibility, rumen fermentation, and rumen microbiota in uncastrated Xiangzhong black cattle. Methods: Twenty-one uncastrated Xiangzhong black cattle (385.08±15.20 kg) aged 1.5 years were randomly assigned to the control group (CL, 0 mg/kg NA in concentrate diet), NA1 group (800 mg/kg NA in concentrate diet) and NA2 group (1,200 mg/kg NA in concentrate diet). All animals were fed a 60% concentrate diet and 40% dried rice straw for a 120-day feeding experiment. Results: Supplemental NA not only enhanced the apparent nutrient digestibility of acid detergent fiber (p<0.01), but also elevated the rumen acetate and total volatile fatty acid concentrations (p<0.05). 16S rRNA gene sequencing analysis of rumen microbiota revealed that dietary NA changed the diversity of rumen microbiota (p<0.05) and the abundance of bacterial taxa in the rumen. The relative abundances of eight Erysipelotrichales taxa, five Ruminococcaceae taxa, and five Sphaerochaetales taxa were decreased by dietary NA (p< 0.05). However, the relative abundances of two taxa belonging to Roseburia faecis were increased by supplemental 800 mg/kg NA, and the abundances of seven Prevotella taxa, three Paraprevotellaceae taxa, three Bifidobacteriaceae taxa, and two operational taxonomic units annotated to Fibrobacter succinogenes were increased by 1,200 mg/kg NA in diets. Furthermore, the correlation analysis found significant correlations between the concentrations of volatile fatty acids in the rumen and the abundances of bacterial taxa, especially Prevotella. Conclusion: The results from this study suggest that dietary NA plays an important role in regulating apparent digestibility of acid detergent fiber, acetate, total volatile fatty acid concentrations, and the composition of rumen microbiota.