Toxicity
The chapter describes metal toxicity (Lead, Zinc, Mercury, Copper, Iron, Arsenic), organophosphate toxicity, organochlorine toxicity and polytetrafluroethyelene (teflon) toxicity in pet birds with remedies.
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Toxicity Indranil Samanta and Samiran Bandyopadhyay
4.1
Heavy Metal Toxicity
Heavy metals (lead, zinc, mercury, cobalt, nickel, cadmium, selenium) are potent toxic substances and are included in the world health organization’s (WHO) list of chemicals with public health concern. Toxicity of heavy metals depends on their oxidative state (redox-active and redox-inactive) in the environment and their reactions with other compounds. Redox-active metals (copper, iron) can generate reactive hydroxyl radicals which are toxic for cellular mitochondria, microsomes and peroxisomes. Redox-inactive metals (lead, nickel, cadmium) destroy cellular antioxidants (e.g. glutathione). Exposure to heavy metals for prolonged period can cause decline in carotenoid levels, survival period, reproductive performances, expression of singing behaviour and feather brightness; oxidative stress and genetic alterations in passerine birds such as in pied flycatchers (Ficedula hypoleuca) and great tits (Parus major). Offspring sex-ratio is not altered in great tits (Parus major) exposed to heavy metals. Feather of birds (great tits, blackbirds, robins, blackcaps, raptors, seabirds) act as an indicator (‘biomonitor’) for accumulation of heavy metal in birds as well as in the local environment. Origin of heavy metal in feathers is either exogenous (from contaminated dust, sand, vegetables and water) or endogenous (from contaminated blood during formation of keratin). Lead and cadmium are mostly exogenous and mercury is considered as endogenous metal. The birds prefer to deposit or excrete the heavy metals in their feathers, uropygial glands, salt glands, eggs and egg shells.
4.1.1 Lead Toxicosis (Plumbism) Lead toxicosis is reported from parrots, wild kea (Nestor notabilis), raptors and wild waterfowls. Ingestion is the major route of lead transfer into the birds from the environment. The plants in lead rich soils can accumulate the lead in their fruits and © Springer Nature Singapore Pte Ltd. 2017 I. Samanta and S. Bandyopadhyay, Pet Bird Diseases and Care, DOI 10.1007/978-981-10-3674-3_4
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Toxicity
leaves. Transfer of lead to the birds occurs through the consumption of fruits, insects and soils (ground foraging birds). In households, paint, lead batteries, wine bottle tops, curtain weights, windows, electrical clips, car exhaust fumes act as major source of lead toxicosis. Ingested lead usually remains in the GI tract for a long time and following degradation in the proventriculus or gizzard, this is being slowly released in blood. Lead is deposited in soft tissues and bone over the time. Lead has severe impact over multiple organs. It causes necrosis of the epithelial lining of GI tract and damage to the endothelial cells. It also causes increased fragility of the erythrocytes and bone marrow suppression leading to reduced generation of RBCs and other blood cells. Degeneration of brain capillaries may cause severe cerebral oedema. Lead concentration of 0.2 ppm and above in blood is considered as toxic. Acute lead poisoning causes
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