Historical Profiles of Trace Element Concentrations in Mangrove Sediments from the Ba Lat Estuary,Red River,Vietnam

Historical profiles of trace element concentrations were reconstructed from two mangrove sediment cores collected within the Ba Lat Estuary (BLE), Red River, Vietnam. Chronologies of sediment cores were determined by the ²¹⁰Pb method, which showed that each respective sediment core from the south and north entrances of BLE provided a record of sediment accumulation spanning approximately 100 and 60 years. The profiles of Pb, Zn, Cu, Cr, V, Co, Sb, and Sn concentrations markedly increased from the years of the 1920s–1950s, and leveled out from 1950s–1980s, and then gradually decreased from 1980s to present. The profiles of Cd and Ag concentrations increased from 1920s–1940s, and then decreased from 1940s to present. The profile of Mo concentrations progressively increased from 1920s–1980s, then decreased to present. The Mn concentrations failed to show a clear trend in both sediment cores. Results from contamination factors, Pearson’s correlation, and hierarchical cluster analysis suggest that the trace elements were likely attributed to discharge of untreated effluents from industry, domestic sewage, as well as non-point sources. Pollution Load Index (PLI) revealed levels higher than other mangrove sediment studies, and the long-term variations in PLI matched significant socioeconomic shifts and population growth in Vietnam. Geoaccumulation Index showed that mangrove sediments were moderately polluted by Pb and Ag, and from unpolluted to moderately polluted by Zn, Cu, and Sb. The concentrations of Pb, Zn, Cu, Cr, and Cd exceeded the threshold effect levels and effect range low concentrations of sediment quality guidelines, implying that the sediments may be occasionally associated with adverse biological effects to benthic organisms.     

Occurrence and characterization of tomato spotted wilt orthotospovirus isolated from cucumber

European Journal of Plant Pathology - Diseases associated with tomato spotted wilt orthotospovirus (TSWV) are a serious threat to vegetable production worldwide. In 2019, leaf necrosis disease was...     

Effects of Dietary Brown Rice on the Growth Performance,Systemic Oxidative Status,and Splenic Inflammatory Responses of Broiler Chickens under Chronic Heat Stress

The aim of this study was to evaluate the effects of dietary brown rice on the growth performance, systemic oxidative status, and splenic inflammatory responses of broiler chickens under both thermo-neutral and chronic heat stress conditions. Forty 12-day-old male broiler chickens (ROSS 308) were randomly assigned to two groups and fed either a control diet (corn-based) or a brown rice-based diet. After seven days (19 days old), both groups were randomly divided into two sub-groups (n=10), one of which was exposed to heat stress (33°C for 14 days), while the other was maintained at 24°C. Heat exposure reduced the body weight gain and feed intake (p<0.01) of both groups. In terms of oxidative plasma states, heat exposure reduced the glutathione peroxidase activity and increased the ceruloplasmin content, while the 2-thiobarbituric acid reactive substance and reduced glutathione levels were not affected adversely. Heat exposure activated the immune responses, as evidenced by increased plasma immunoglobin levels, and altered splenic immune-related gene expressions including heat shock proteins, toll-like receptor 4, and interleukin-12. Under both thermo-neutral and heat stress conditions, dietary brown rice improved the growth performance, decreased the immunoglobulin levels, and down-regulated the expression of splenic immune-related genes of broilers, although their systemic oxidative status was not affected. Dietary brown rice should be considered as a valuable component of broiler chicken feeds subjected to both thermo-neutral and heat stress conditions. The positive effects of brown rice on bird performance may be associated with the modulation of the immune responses, as reflected by the decreased production of immunoglobulins and altered splenic immune-related gene expression.