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The Land surface of the Sichuan Basin is characterized by complexity and diversity， with frequent occurrences of heavy rainfall.This study utilizes global reanalysis data from the U.S.National Centers for Environmental Prediction and various categories of land use data， including default land use data from the WRF model， MODIS （Moderate Resolution Imaging Spectroradiometer）， and USGS （United States Geological Survey）.Additionally， the 2015 LUCC2015 （Land use datasets in China 2015） datasets and the 2015 GLASS （Global Land Surface Satellite） land use datasets are incorporated.The WRF（Weather Research and Forecasting）model is used to simulate a heavy rainfall event in Sichuan Province.The impact of changes in land surface classification and variations in terrain height on heavy rainfall is discussed through four sets of land use experiments and two sets of terrain sensitivity experiments.The results indicate that the experiments involving different land use types have a significant impact on regions experiencing heavy precipitation.In comparison to the MODIS experiment， the precipitation distribution from the USGS experiment is more concentrated， with a larger coverage area for intense precipitation centers； the LUCC2015 experiment results in a reduction in rainfall intensity in the northeastern part of the Sichuan Basin， accompanied by a more concentrated precipitation distribution； the GLASS experiment simulation， characterized by a relatively uniform land use， results in a reduction in the intensity of both intense precipitation centers.Additionally， the precipitation centers in the northeastern part of Sichuan shift southward.Various land use types also exert influence on near-surface meteorological parameter fields.Through a comprehensive analysis of the various land use experiments， it is evident that a reduction in urban built-up areas results in a decrease in 2 m temperature by 0.5 to 1 ℃； the reduction in vegetation coverage results in an increase in 2 m temperature and an enhancement of 10 m wind speed； the decrease in surface roughness leads to a significant enhancement in 10 m wind speed， with a magnitude of change ranging from 2 to 4 m·s-1.Compared to the default land use types in WRF， the simulated results under the underlying surface types in the LUCC2015 experiment are better.The topography exerts a pronounced influence on heavy rainfall.Following the reduction in elevation of the western mountainous region in the basin， the absence of mountain barriers allows for a more abundant presence of lower-level water vapor and energy.Consequently， moisture and energy can be transported to more northern regions of Sichuan.With the reduction in elevation of the terrain， the low-level airflow intensifies convergence ahead of the mountains， triggering stronger upward motion of air and resulting in enhanced precipitation intensity.This phenomenon leads to a westward shift in the precipitation location and a more concentrated coverage of rainfall.Conversely， with the uplift of the terrain， the mountainous barrier impedes the entry of warm and moist airflow from the south.As a result， energy and moisture become more dispersed， causing a reduction in airflow convergence in the western and eastern parts of the basin.The weakening of low-level airflow ascent leads to a decrease in precipitation intensity and a more dispersed distribution of rainfall.

This study uses the Weather Research Forecast Model （WRF） numerical forecast system and the Three-Dimensional Variational Data Assimilation （WRF-DA） system to investigate the impact of assimilating data from the Micro-Wave Humidity Sounder 2 （MWHS-2） onboard FY-3C and the Microwave Humidity Sounder （MHS） from NOAA-19 （National Oceanic and Atmospheric Administration-19） on the simulation and prediction of heavy rainfall events in the Yarlung Zangbo Grand Canyon.Three assimilation schemes are compared： the control （Con） scheme， the NOAA-19 scheme （MHS） and the FY-3C scheme （MWHS-2）.The results indicate that assimilation of MHS and MWHS-2 microwave radiance data using WRF-3DVAR （Three-Dimensional Variation） improves the simulation performance compared to the Con experiment.It improves the accuracy of the precipitation location， although the MWHS-2 experiment shows a northern bias in the precipitation area.Satellite data assimilation significantly improves the moisture field， but its effect on heavy rain intensity is less pronounced than its effect on precipitation area improvement.Data assimilation enhances the 700 hPa meridional wind component， leading to increased moisture transport within the study area.With respect to temperature， the assimilation of satellite microwave moisture data has a moderately positive effect， which forming an unstable vertical temperature structure in the 700~400 hPa layer， conducive to the generation and development of precipitation.Overall， the simulation results of the MHS experiment outperform those of MWHS-2， especially in the wind field， temperature and humidity fields.In addition， the root mean square error changes in the 24-hour forecast of the MWHS-2 experiment are relatively stable， indicating that MWHS-2 satellite data are more advantageous for medium to long-term simulation studies.

Abstract Docosahexaenoic acid (DHA) can improve human and animal health, particularly including anti-inflammatory, antioxidant, anticancer, neurological, and visual functions. Schizochytrium sp. is a marine heterotrophic protist producing oil with high DHA content, which is widely used in animal and food production. However, different fermentation conditions have intensive impacts on the growth and DHA content of Schizochytrium sp. Thus, this study aimed to enhance the DHA yield and concentration of Schizochytrium sp. I-F-9 by optimizing the fermentation medium. First, a single-factor design was conducted to select a target carbon and nitrogen source from several generic sources (glucose, sucrose, glycerol, maltose, corn syrup, yeast extract, urea, peptone, and ammonium sulfate). The Plackett–Burman design and the central composite design (CCD) were utilized to optimize the fermentation mediums. Schizochytrium sp. in 50-mL fermentation broth was cultured in a 250 mL shake flask at 28 °C and 200 rpm for 120 h before collecting the cell pellet. Subsequently, the cell walls were destroyed with hydrochloric acid to extract the fatty acid using n-hexane. The DHA content was detected by gas chromatography. The single-factor test indicated that glucose and peptone, respectively, significantly improved the DHA content of Schizochytrium sp. compared to the other carbon and nitrogen sources. Glucose, sodium glutamate, and sea crystal were the key factors affecting DHA production in the Plackett–Burman test (P = 0.0247). The CCD result showed that DHA production was elevated by 34.73% compared with the initial yield (from 6.18 ± 0.063 to 8.33 ± 0.052 g/L). Therefore, the results of this study demonstrated an efficient strategy to increase the yield and content of DHA of Schizochytrium sp.

Disease is the main reason for the use of antimicrobials in calf rearing, and antibiotics are commonly used to treat calves, including for unknown diseases. This leads to antimicrobial resistance, which is a challenge to the livestock industry and public health. Plant products containing high levels of phytochemicals may improve the immunity and resistance of calves against infections, thereby reducing the use of antimicrobials. This study aimed to investigate the effect of Phyllanthus emblica (Amla) fruit powder (PE) supplementation on antioxidant capacity and immune response of preweaning dairy calves. One hundred, 2-day-old, male Holstein calves were randomly assigned into five treatment groups receiving 0, 5, 10, 20, and 40 g/d PE supplementation. Antioxidant and immune indices and pro- and anti-inflammatory cytokines were analyzed from serum samples, whereas 16S rRNA was analyzed from rumen fluid and fecal samples. PE supplementation, at 5 g/d, protected calves against oxidative stress and improved antioxidant enzymes and immune and anti-inflammatory responses, showing its immunity-enhancing and protective roles against infections. However, the antioxidant capacity and immune response decreased with increasing PE levels, illustrating the adverse effects of PE supplementation at higher doses. The analysis of ruminal and fecal bacterial community abundance detected higher proportions of Firmicutes at an early age, and a higher Bacteroidetes to Firmicutes ratio at weaning, in calves supplemented with 5 g/d PE. This contributed to the development of the immune system in early life, and improved immune and anti-inflammatory responses at a later age. The overall results suggest that PE could be supplemented at 5 g/d for preweaning dairy calves to protect against oxidative stress and infections while maintaining normal gut microbial hemostasis.

ABSTRACT We evaluated the difference between rumen bacteria in Tan sheep fed either by grazing or in a feedlot. The aim was to provide a theoretical basis for ruminant nutrition and meat quality based on rumen fermentation. Twenty-four three-month-old Tan sheep were randomly and equally divided into two groups, the grazing group and ration group. Five sheep of each group were selected for slaughter at six months of age. Ruminal contents were collected and assessed to identify rumen bacteria, based on 16S rDNA sequencing analysis. A total of 17 phyla were identified, among which Bacteroidetes, Firmicutes, and Proteobacteria were dominant in both groups. The abundance of Firmicutes was higher in grazing group than in the ration group, while that of Proteobacteria was opposite. Besides the dominant phyla differences, the abundance of Fibrobacteres, Tenericutes, Elusimicrobia, and Cyanobacteria was significantly higher in the grazing group compared with the ration group. At genus level, a total of 174 genera were identified. The abundance of Rikenellaceae_RC9_gut_group, Dialister, Lachnospiraceae_NA, Catonella, Ruminococcaceae_UCG-014, Lachnospiraceae_NK3A20_group, and Fibrobacter in the grazing group was higher than in the ration group. However, the abundance of Succinivibrionaceae_NA was lower in the grazing group, and Succinivibrionaceae_UCG-001 showed a decreasing trend in the grazing group. The two feeding methods may influence the rumen bacterial composition, including the abundance of dominant bacteria, as well as the cellulolytic- and carbohydrate-degrading bacteria in the rumen of Tan sheep.