Toxins and Poisons

Mycotoxicoses

INTRODUCTION A mycotoxicosis is a disease caused by a toxic metabolite of fungi (mycotoxin). Hundreds of mycotoxins are recognized, but the toxicity, occurrence, and target organs are varied among these naturally occurring toxins.

Ergotism is caused by Claviceps spp., which attack cereal grains. Aflatoxins are highly toxic and carcinogenic mycotoxins produced by A. flavus, A. parasiticus, and Penicillium puberulum. Hepatotoxicity is the primary effect in nearly all animals. Ergotism is caused by Claviceps spp., which attack cereal grains. Ergotism is characterized by vascular, neurologic, and endocrine disorders.

Moniliformin is produced by Fusarium moniliforme and other Fusarium spp. Cardiotoxic and nephrotoxic in poultry.

Ochratoxins are among the most toxic mycotoxins to poultry Ochratoxins are among the most toxic mycotoxins to poultry. These nephrotoxic metabolites are produced chiefly by Penicillium viridicatum and Aspergillus ochraceous.

DIAGNOSIS Diagnosis of a mycotoxicosis begins with the assessment of the clinical history and signs. A definitive diagnosis of mycotoxicosis involves identification and quantification of specific toxins. Analytic techniques for mycotoxins include chromatography (thin-layer, gas, liquid), mass spectrometry, and monoclonal antibody-based technology.

TREATMENT Toxic feed should be removed and replaced with unadulterated feed. Increasing the crude protein, dietary energy, and vitamin supplementation can counteract the effects of aflatoxin. Substandard management practices are especially detrimental to poultry stressed by mycotoxins and should be corrected.

PREVENTION Feed Manufacturing and Management Antifungal Agents Organic acids Detoxification with Adsorbents Inorganic mineral adsorbents or binders including various clays, soils, and zeolites

Poisons Poisons are not major causes of production loss or disease in poultry in most countries, although some, such as lead, pesticides, and botulism, are significant in wild birds.

Poisoning occurs more frequently in free- range and backyard flocks and in village poultry where birds forage in neighboring gardens and fields or receive household waste and weeds cut from roadsides and fields.

ANTIMICROBIALS, ANTICOCCIDIALS, AND GROWTH PROMOTANTS Most reports of poisoning with chemotherapeutic agents involve inappropriate use or overdose of anticoccidials or growth promotants. Sulfonamides were used as the primary form of prevention and treatment for coccidiosis. Difficult to mix evenly in feed, and they have low solubility in acidic water. Hemorrhagic syndrome.

In adults, there is a marked decrease in egg production and shell quality; brown eggs may be depigmented

Aminoglycoside Antibiotics After subcutaneous injection, gentamicin causes depression in turkey poults, edema and hemorrhages at the injection site, and large, pale, and nephrotic kidneys

ANTHELMINTICS All anthelmintics are probably toxic if a sufficient overdose is given, but generally birds are more resistant than mammals to anthelmintics. Levamisole, tetramisole and Ivermectin

Arsenic: Toxic effects include diarrhea, nervous signs, and cyanosis Arsenic: Toxic effects include diarrhea, nervous signs, and cyanosis. There is inflammation of the digestive tract including crop, proventriculus, and gizzard, hepatosis, and nephrosis. Lead: Clinical disease usually is seen as wasting, ataxia, lameness or paralysis, and anemia.

Vitamin A: Excess vitamin A reduces egg production and growth rate and causes osteodystrophy and osteoporosis. Vitamin D3 (cholecalciferol): kidney failure occur in chicks.

DISINFECTANTS AND FUMIGANTS Fumigants are products producing toxic gases used to control rodents, insects, fungi, and bacteria. They can cause toxicity when inhaled or ingested. Phenolic disinfectants can be toxic when inhaled or absorbed through skin.