Plant essential oils improve growth performance by increasing antioxidative capacity, enhancing intestinal barrier function, and modulating gut microbiota in Muscovy ducks

ABSTRACT: Essential oils (EO) are known for their antioxidant, anti-inflammatory, antimicrobial, and growth-promoting properties. However, data rgarding their impact on the intestinal health and gut microbiota of ducks remain limited. Thus, this study aimed to investigate the effects of plant EO on the growth performance, intestinal health, and gut microbiota of Muscovy ducks. A total of 360 healthy male Muscovy ducks aged 1 d were randomly divided into 4 groups with 6 replicates and 15 ducks per replicate. Ducks were fed basal diets supplemented with 0, 100, 200, or 300 mg/kg EO. The results showed that 200 mg/kg EO supplementation significantly (P < 0.05) increased the final body weight and average daily gain, while significantly (P < 0.05) decreased the feed conversion ratio during the 56-d experimental period. Furthermore, dietary 200 mg/kg EO significantly (P < 0.05) enhanced antioxidant capacity and immune function and improved the barrier function of the intestine. Additionally, 16S rDNA sequencing analysis results showed that 200 mg/kg EO favorably modulated the cecal microbial diversities and composition evidenced by the increased (P < 0.05) the abundances of short-chain fatty acid-producing bacteria (e.g., Subdoligranulum and Shuttleworthia) and decreased (P < 0.05) abundances of potential enteric pathogenic bacteria (e.g., Alistipes, Eisenbergiella, and Olsenella). The relative abundance of beneficial bacteria was positively correlated with antioxidant, immune, and barrier function biomarkers. Overall, these findings revealed that dietary supplementation with 200 mg/kg EO had several potentially beneficial effects on the growth performance of Muscovy ducks by improving antioxidant capacity, enhancing the intestinal barrier function and favorably modulating gut microbiota

Antioxidant Properties of Probiotic Bacteria

Oxidative stress defines a condition in which the prooxidant–antioxidant balance in the cell is disturbed, resulting in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells’ viability. Probiotics have been known for many beneficial health effects, and the consumption of probiotics alone or in food shows that strain-specific probiotics can present antioxidant activity and reduce damages caused by oxidation. However, the oxidation-resistant ability of probiotics, especially the underling mechanisms, is not properly understood. In this view, there is interest to figure out the antioxidant property of probiotics and summarize the mode of action of probiotic bacteria in antioxidation. Therefore, in the present paper, the antioxidant mechanisms of probiotics have been reviewed in terms of their ability to improve the antioxidant system and their ability to decrease radical generation. Since in recent years, oxidative stress has been associated with an altered gut microbiota, the effects of probiotics on intestinal flora composition are also elaborated

Environmental Influences on Forest Fire Regime in the Greater Hinggan Mountains, Northeast China

Fires are the major disturbances in the Greater Hinggan Mountains, the only boreal forest in Northeast China. A comprehensive understanding of the fire regimes and influencing environmental parameters driving them from small to large fires is critical for effective forest fire prevention and management. Assisted with satellite imagery, topographic data, and climatic records in this region, this study examines its fire regimes in terms of ignition causes, frequencies, seasonality, and burned sizes in the period of 1980–2005. We found an upward trend for fire occurrences and burned areas and an elongated fire season over the three decades. The dates of the first fire in a year did not vary largely but those of the last fire were significantly delayed. Topographically, spring fires were prevalent throughout the entire region, while summer fires mainly occurred at higher elevations under severe drought conditions. Fall fires were mostly human-caused in areas at lower elevations with gentle terrains. An ordinal logistic regression revealed temperature and elevation were both significant factors to the fire size severity in spring and summer. Other than that, environmental impacts were different. Precipitation in the preceding year greatly influenced spring fires, while summer fires were significantly affected by wind speed, fuel moisture, and human accessibility. An important message from this study is that distinct seasonal variability and a significantly increasing number of summer and fall fires since the mid-1990s suggest a changing fire regime of the boreal forests in the study area. The observed and modeled results could provide insights on establishing a sustainable, localized forest fire prevention strategy in a seasonal manner

Unprecedented snow darkening and melting in New Zealand due to 2019–2020 Australian wildfires

Wildfire events have recently shown a rapid increase in frequency and scale due to the warmer present-day climate; however, their potential effects on the cryosphere are difficult to assess. Catastrophic wildfires in Australia during 2019–2020 emitted large amounts of light-absorbing particles (LAPs) to the atmosphere. Satellite observations indicate that these LAPs caused unprecedented snow-darkening of glaciers in New Zealand through long-range transport and deposition, with their effects lasting for up to three months in January–March 2020, influencing >90% of total glacier/snow and leading to a mean broadband snow-reflectance reduction of 0.08 ± 0.03. This snow darkening accelerated snowmelt by ~0.41 ± 0.2 cm day–1 during the southern summer, equivalent to that caused by a ~1.8 °C increase in air temperature. This indicates the significant impact of the 2019–2020 Australian wildfires on the hydrologic cycle in New Zealand, exceeding that of the local climate warming of ~1.5 °C since the preindustrial period. Wildfire-induced snow darkening is not limited to New Zealand. Future projections of wildfire incidence indicate widespread effects of snow darkening on the global cryosphere

Historical Changes of Black Carbon in Snow and Its Radiative Forcing in CMIP6 Models

Black carbon in snow (BCS) has a significant impact on global climate and is an important component of Earth system modeling. Here, we provide a comprehensive evaluation of BCS simulations in the Coupled Model Intercomparison Project Phase 6 (CMIP6) and its radiative forcing on a global scale. Overall, the multi-model mean generally captures the characteristics of BCS spatial patterns, with maximum concentrations in East Asia and the Tibetan Plateau (~120 ng&middot;g&minus;1), and the lowest in Antarctica (~0.05 ng&middot;g&minus;1). The BCS concentrations in all CMIP6 multi-model mean and individual models generally exhibit a temporally increasing trend globally, with particularly large increases after the 1940s. In terms of seasonal cycles, individual models are generally consistent in most regions. Globally, BCS concentrations are highest around January and lowest in September. The albedo reduction in the Tibetan Plateau and East Asia simulated by the CMIP6 multi-model mean reached ~0.06 in 2014 and may influence climate more than expected

Historical Changes of Black Carbon in Snow and Its Radiative Forcing in CMIP6 Models

Black carbon in snow (BCS) has a significant impact on global climate and is an important component of Earth system modeling. Here, we provide a comprehensive evaluation of BCS simulations in the Coupled Model Intercomparison Project Phase 6 (CMIP6) and its radiative forcing on a global scale. Overall, the multi-model mean generally captures the characteristics of BCS spatial patterns, with maximum concentrations in East Asia and the Tibetan Plateau (~120 ng·g−1), and the lowest in Antarctica (~0.05 ng·g−1). The BCS concentrations in all CMIP6 multi-model mean and individual models generally exhibit a temporally increasing trend globally, with particularly large increases after the 1940s. In terms of seasonal cycles, individual models are generally consistent in most regions. Globally, BCS concentrations are highest around January and lowest in September. The albedo reduction in the Tibetan Plateau and East Asia simulated by the CMIP6 multi-model mean reached ~0.06 in 2014 and may influence climate more than expected

Divergent features of the upper-tropospheric carbonaceous aerosol layer: effects of atmospheric dynamics and pollution emissions in Asia, South America, and Africa

The upper-tropospheric carbonaceous aerosol layer (TCAL) represents the increase of aerosols in the upper-troposphere. It was first discovered over Asia but was found in this study to also occur over South America and Africa. The TCALs over three regions typically exist during the strong deep convection season, with the Asian, South American, and African TCALs showing peak intensity during July–August, October–December, and November–December, respectively. Over Asia, the TCAL has the highest altitude and widest spread due to strongest deep convection and upper-troposphere anticyclonic system. TCAL intensity is highest in South America maybe due to heaviest pollutant emissions. Anthropogenic pollution from India and western China produces two Asian TCAL centers, whereas widespread wildfires result in single centers over South America and Africa. TCAL radiative effect at the top of the atmosphere has warming effects over Asia (+0.23 W m ^−2 ), whereas cooling effects perform over South America (−0.54 W m ^−2 ) and Africa (−0.20 W m ^−2 ) owing to its altitude and the divergent strengths of black-carbon absorption and organic-carbon scattering

Which global reanalysis dataset has better representativeness in snow cover on the Tibetan Plateau?

&lt;jats:p&gt;Abstract. The extensive snow cover across the Tibetan Plateau (TP) has a major influence on the climate and water supply for over 1 billion downstream inhabitants. However, an adequate evaluation of variability in the snow cover fraction (SCF) over the TP simulated by multiple reanalysis datasets has yet to be undertaken. In this study, we used the Snow Property Inversion from Remote Sensing (SPIReS) SCF dataset for the water years (WYs) 2001–2017 to evaluate the capabilities of eight reanalysis datasets (HMASR, MERRA2, ERA5, ERA5L, JRA55, CFSR, CRAL, and GLDAS) in simulating the spatial and temporal variability in SCF in the TP. CFSR, GLDAS, CRAL, and HMASR are good in simulating the spatial pattern of climatological SCF, with lower bias and higher correlation and Taylor skill score (SS). By contrast, ERA5L, JRA55, and ERA5 have a relatively good performance in terms of SCF annual trends among eight reanalysis datasets. The biases in SCF simulations across reanalysis datasets are influenced by a combination of meteorological forcings, including snowfall and temperature, as well as by the SCF parameterization methods. However, the primary influencing factors vary among the reanalysis datasets. Additionally, averaging multiple reanalysis datasets can enhance the spatiotemporal accuracy of SCF simulations, but this enhancement effect does not consistently increase with the number of reanalysis datasets used. &lt;/jats:p&gt

Polysaccharide from Hericium erinaceus improved laying performance of aged hens by promoting yolk precursor synthesis and follicle development via liver-blood-ovary axis

ABSTRACT: Little information is available on the effect of Hericium erinaceus polysaccharides (HEP) on laying hens, especially on improving liver and ovarian health and function. Therefore, this study was conducted to investigate the impacts of HEP on liver and ovarian function to delay the decline in the laying performance of aged hens. A total of 360 fifty-eight-wk-old laying hens were randomly allocated to 4 treatments, with 6 replicates of 15 birds each. After 2 wk of adaptation, the birds were fed basal diet (CON) or basal diets supplemented with 250, 500, and 750 mg/kg of HEP (HEP250, HEP500, and HEP 750, respectively) for 12 wk. The results showed that, compared with CON, hens fed HEP had significantly increased laying performance (P < 0.05) and promoted follicle development, as evidenced by the increased numbers of hierarchical follicles, small follicles, and total follicles (P < 0.05). Birds fed 500 mg/kg of HEP improved the liver function by increasing T-AOC activity (P < 0.05) and decreasing hepatic oxidative stress and inflammatory responses (inflammatory cell infiltration) caused by aging. The lipid metabolism was improved, and yolk precursor synthesis was promoted in the liver of HEP-treated laying hens by upregulating the mRNA expression of FAS, MTTP, PPAR-α, APOVLDL-Ⅱ, and VTG-Ⅱ (P < 0.05). In addition, HEP significantly decreased ovarian inflammation by regulating the mRNA levels of NF-κB, IL-1β, IL-6, and TNF-α (P < 0.05). As a result, the contents of E2, LH, and FSH in serum and the gene expression of ERα of the liver and FSHR of the ovary increased in HEP-treated hens (P < 0.05). In conclusion, dietary HEP supplementation exhibited potential hepatic and ovarian protective effects, thereby increasing the laying performance of aged hens by enhancing reproductive hormone secretion hormone secretion and promoting yolk precursor synthesis and follicle development via the liver–blood–ovary axis. The optimal supplementation level of HEP in aged hens was 500 mg/kg

Differences in Sulfate Aerosol Radiative Forcing between the Daytime and Nighttime over East Asia Using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) Model

The effect of aerosols is an important indicator of climate change. Sulfate aerosols, as the major scattering aerosols, which have attracted more and more attention in recent years. The Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) were utilized to investigate the spatial distribution of sulfate aerosols and their radiative forcing characteristics over East Asia in 2010. Results showed that sulfate aerosols were mainly distributed over eastern China (24&#8315;43&#176; N, 101&#8315;126&#176; E), especially in the Sichuan Basin. The concentration of sulfate aerosols decreased with increasing altitude over East Asia. It also exhibited obvious seasonal variations, where the largest range of sulfate aerosol concentrations was found in summer, with a maximum of 2.4 &#956;g kg&#8722;1 over eastern China. Although sulfate aerosol concentrations varied slightly during day and night, there was still a significantly difference in the sulfate aerosol radiative forcing. Specifically, the magnitude of the direct radiative forcing induced by sulfate aerosols at the surface was approximately &#8722;3.02 W m&#8722;2 in the daytime, while that was +0.24 W m&#8722;2 in the nighttime. This asymmetric change that was caused by the radiative forcing of sulfate aerosols between day and night would have significant impacts on climate change at the regional scale