Mercury pollution has been studied in Finland since 1960. In the 1960 's, industrial use of Hg was about 50 t yr−1, 80% of which was consumed by chlor-alkali plants. In the 1980's, about 19, to 25 t yr−1 Hg was used and compared to past consumption, its use has decreased by 40 to 50%. In 1987, the import of Hg through raw materials
and other sources in Finland was, however about 170 t yr−1 which is rather high. There are no detailed statistics about Hg emissions in the 1960's. In 1967, air and water emissions
of Hg were 2.8 and 8.3 t yr−1 respectively. In 1987, estimated air emission of Hg was 3.48 t yr−1 whereas water emission was 0.15 t yr−1 Aquatic emission has been lowered by 50% which is due to the fact that pulp and paper industries stopped using Hg as slimicide.
On the other hand, the air emission of Hg has not decreased. This is due to the high Hg content in raw materials used by metallurgical
and power plants. 相似文献
Dirofilaria immitis is the causative agent of cardiopulmonary dirofilariasis in the Canine family. The aim of the study was to evaluate the efficacy of the ethanolic extract of Azadirachta indica leaves (EEA) against the microfilaria (mf) of D. immitis in vitro. EEA was evaluated for different compound classes through HPTLC. Relative motility, mortality and morphological alterations were observed in the mf after exposure to EEA. The effect of EEA on redox status in the treated mf was evaluated by some key enzymatic and non-enzymatic parameters. An enhanced reactive oxygen species (ROS) level in the treated mf along with altered redox status was evident. DNA fragmentation and terminal-deoxynucleotidyl-transferase dUTP nick end labeling (TUNEL) confirmed apoptosis. In addition, western blotting revealed down-regulation of anti-apoptotic protein and up-regulation of pro-apoptotic proteins. Taken together, the microfilaricidal activity of EEA can be attributed to its capacity to inflict oxidative stress culminating in apoptosis. 相似文献
A 2 × 2 × 2 factorial experiment was designed to study the effect of microbial phytase (MP), citric acid (CA), and crude protein (CP) and their interactions on mineral utilization by rohu, Labeo rohita, juveniles. Two basal diets containing 25% (subnormal) or 35% (normal) CP were supplemented with MP (units, U/kg) and CA (%) at 0, 0; 500, 0; 0, 3; and 500, 3, respectively and fed to 125 juveniles (average initial weight: 13.16 g/fish). MP did not affect fecal ash content but CA (3%) addition activated MP. Apparent absorption of Zn, its content in whole body and plasma, was significantly (P < 0.05) higher in CA‐ and MP‐fed groups. Interaction between CA and MP was found for increased absorption of Na, P, K, Mn, Mg, Fe, and N, their concentrations in whole body and plasma. Cu and Ca absorption, and their concentration in body and plasma were increased as a result of addition of CA, MP, or their interaction. Thus, bioavailability of major minerals was highest in groups fed diets containing 500‐U MP and 3% CA. This improvement was more prominent in subnormal CP diet. Growth performance was also highest in this group. Thus, CA and MP at 25% CP diet had synergistic effect on mineral bioavailability in L.rohita. 相似文献
A 60‐day feeding trial was conducted to quantify the effects of microbial phytase supplementation on apparent absorption, whole body and bone contents of minerals in Pangasius pangasius fingerlings. Seven isoprotein (35.67%) and isocaloric (3870 kcal kg?1) diets were prepared with graded levels of supplemental phytase at 0 (T1), 150 (T2), 250 (T3), 350 (T4), 500 (T5), 1000 (T6) and 2000 (T7) FTU (Phytase Units) kg?1. Three hundred and fifteen fingerlings of P. pangasius (1.97–2.05 g) were randomly distributed in seven treatments with three replicates each. There was significant increase (P<0.05) in tissue protein content in phytase‐supplemented groups compared with the control. Apparent absorptions of calcium (Ca), phosphorus (P), magnesium (Mg), manganese (Mn), zinc (Zn), iron (Fe), potassium (K), copper (Cu) and cobalt (Co) were significantly (P<0.05) higher in the phytase‐supplemented groups than the control group. Faecal ash and P contents were significantly (P<0.05) higher in the control (T1) than the phytase‐supplemented groups. Whole‐body contents of Ca, P, Zn, Fe, Cu and Co were significantly (P<0.05) improved by the dietary supplementation of phytase‐barring Mg and Mn. Concentrations of bone Ca, P, K, Cu and Co were significantly (P<0.05) higher in phytase‐supplemented groups. Bone ash contents (40.77–44.85%) were increased concomitantly with the increased level of phytase inclusion upto 500 FTU kg?1 diet. It was observed that a minimum dose of 250 FTU phytase kg?1 diet improved the mineral absorption and utilization in P. pangasius fingerlings. 相似文献
Trametes versicolor is a mushroom used as a traditional Chinese medicine (Yun-zhi) for a wide array of seemingly disparate conditions. We hypothesized that many of its multiple purported activities could be mediated through stimulation of beneficial mutualist components of the microbiota. Human fecal microbiota was cultured anaerobically to determine its ability to ferment a common extract of T. versicolor, designated polysaccharide peptide (PSP), and the ability of PSP to alter the composition of the microbial community. The presence of PSP and fructooligosaccharides (FOS, a common prebiotic) in the medium, but not cellulose, significantly increased levels of Bifidobacterium spp. PSP also elevated Lactobacillus spp., while reducing Clostridium spp., Staphylococcus spp. and Enterococcus spp. Levels of Streptococcus spp., Bacteroides spp. and Escherichia did not significantly change. Fermentation of PSP increased the concentration of organic acids (lactate and short-chain fatty acids), decreased the pH, and induced β-galactosidase and β-glucosidase activities. The genera of the human microbiota that are promoted by FOS and other prebiotics are also stimulated by the Trametes versicolor extract, PSP. Thus, Trametes versicolor, a common East Asian botanical, contains putative prebiotic agents that alter human gut microbiota and pH. This prebiotic-like activity may help explain some of the plethora of the health benefits attributed to this traditional Chinese medicine. 相似文献
Aquaculture is growing post-haste in recent years particularly in the fish and shrimp production. The rapid growth of aquaculture and increasing demand for fish have led to a rapid development of the fish and shrimp industry, resulting in increased production of both fish and shrimps. As a result, there is a greater risk of disease outbreaks. Mass mortalities in aquaculture are primarily due to infectious diseases caused by bacteria, viruses, and fungi. Among them, viral diseases are the most devastating, causing huge loss in the production of both cultured fish and shellfishes. There are several effective methods of treatment for these disease outbreaks. This review focuses on various methods of controlling the viral pathogens using various treatment methods like use of medicinal plants and seaweed extracts, bioactive compounds from actinomycetes, vaccines, probiotic microbes, chemicals, nanoparticles, and green synthesis of nanoparticles.
The aim of this study was to examine the immunomodulatory effect of high levels of dietary vitamin C in healthy and immunocompromised rohu (Labeo rohita) treated with aflatoxin B1 (AFB1). Four groups of rohu were fed experimental diets containing either no vitamin C or supplemented with vitamin C at 500 ppm for 60 days. On the first day of feeding, one group fed the high vitamin C diet and one fed the vitamin C deficient diet, were injected intraperitoneally with a single doses of AFB1 at 1.25 mg kg(-1) body weight. The effect of AFB1 and high dietary vitamin C on specific and non-specific immunity, and disease resistance against Aeromonas hydrophila were examined in the rohu. The ability of vitamin C to counteract immunosuppression induced by AFB1 was also examined. Specific immunity indicated by haemagglutination and haemolysin titres against sheep red blood cells (SRBC), and bacterial agglutination appeared to be unaffected by either the AFB1 treatment or the vitamin C enriched diet. A significant reduction was observed in the non-specific immunity of AFB1-treated fish, however, indicated by lowered bactericidal and lysozyme activities. High dietary vitamin C, on the other hand, enhanced the non-specific immunity of fish, including an enhanced phagocytic ratio and increased serum lysozyme activity. Feeding a high level of dietary vitamin C to AFB1-treated fish increased these parameters to levels similar to those found in control fish. High dietary vitamin C significantly (p < 0.05) enhanced protection against Aeromonas hydrophila infection in both healthy and immunocompromised fish. Results from this study help to establish the beneficial effect of dietary vitamin C on AFB1-induced immunosuppression, as well as confirming the immunostimulatory effect of vitamin C in rohu. 相似文献