Water pollution Oxygen-depleting substances may be natural materials such as plant matter (e.g. leaves and grass) as well as man-made chemicals. Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs the gills of some fish species. Alteration of water's physical chemistry includes acidity (change in pH), electrical conductivity, temperature, and eutrophication. Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to an extent that increases the primary productivity of the ecosystem. Depending on the degree of eutrophication, subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions
Natural growth promoter Natural growth promoter Natural growth promoters (NGPs) are feed additives for farm animals. Different categories of feed additives for farm animals are referred to as natural growth promoters (NGPs) or non-antibiotic growth promoters. They are commonly regarded as favorable alternatives to antibiotic growth promoters (AGPs) in livestock production. NGPs include predominantly organic acids, probiotics, prebiotics, synbiotics, phytogenics, tannins, feed enzymes and immune stimulants., an ongoing search for alternatives has created a large variety of NGPs for pigs, poultry, ruminants and aquatic species. The main advantage of NGPs over AGPs is that they do usually not bear any risk regarding bacterial