Effects of endocrine disruptors from intensive poultry on fish

LIMA Fish Feed Machine,Chicken Feed Machine

The Delmarva Peninsula, consisting of eastern Maryland, most of Delaware, and the portion of Virginia east of the Chesapeake Bay, is one of the most densely concentrated poultry producing areas in the United States of America. The region generates 600 million birds and 1.6 billion pounds (726 million kg) of manure (or litter) annually. Excessive land application of poultry wastes has precipitated severe water quality problems in surface waters and groundwaters throughout the region. Impacts include harmful algal blooms, decreases in water clarity, widespread anoxia, and declines in submerged aquatic vegetation. Pollutants and pathogens in poultry litter traditionally linked to environmental degradation include nutrients and protozoan, bacterial and viral agents. In addition, recent attention has turned toward various non-traditional poultry litter-associated contaminants. These include feed additives (e.g. trace metals and antibiotics), poultry house/bedding material impurities (e.g. metals and pesticides) and faecal/urinary steroids (e.g. estrogenic and androgenic hormones). In most vertebrates, sex steroids, specifically 17-ß estradiol (E2) and testosterone, are responsible for gender differentiation, development of reproductive structures and stimulation of breeding behaviours. They are released naturally in poultry urine and faeces and persist at high concentrations and for prolonged durations (more than two years) in litter. Studies conducted on the Delmarva Peninsula and elsewhere have demonstrated the transport of E2 from poultry litter-amended fields to surface waters and groundwaters at levels sufficient to warrant environmental concern. The studies have also confirmed that these contaminants are capable of causing endocrine disruption in aquatic animals.

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