Document Type

Thesis - Open Access

Award Date

1970

Degree Name

Master of Science (MS)

Department

Animal Science

Abstract

Ochratoxin is a toxin produced by fungus Aspergillus ochraceus Wilh. This is one of the poisonous metabolites, like aflatoxin, which when ingested by livestock, poultry, and human beings could produce toxigenic effects—so-called mycotoxicoses. The fungus A. ochraceus is widely distributed in nature and often found in soil and vegetation. Scientists, while searching for causative agents of certain diseases not of bacterial, viral, or nutritional origin, conducted a series of experiments a few decades ago using different species of fungi grown on food and feedstuffs. Toxic effects concurrent with antimicrobial activity of certain species of molds created problems in separating one effect from the other. With the advancement of research techniques such as chemical extraction, purification, and different biological assay procedures, these scientists were able to isolate the disease-causing molds, and the so-called mycotoxicoses came to light. Schofield (1924) in Canada first reported on the naturally occurring mycotoxicoses and reproduced the disease experimentally, using different species of molds (Aspergillus species particularly) isolated in his laboratory. He was not a mycologist, but studied the toxicity of varying levels of moldy sweet clover hay. With the type of fungus prevailing on the substrata, he was able to induce in rabbits sign which closely resembled mild cases of sweet clover poising among cattle. Considerable progress has already been made in different parts of the world in isolating the toxic and antibiotic strains of fungus found on contaminated foodstuffs of both plant and animal sources. Toxic metabolites of the genus Aspergillus causing aflatoxicosis (one of several mycotoxicoses) have been thoroughly reviewed since early 1960, whereas ochratoxin, another metabolite of the Aspergillus species, which is supposed to be similar in toxic effects, has escaped extensive research. This toxin was first described by Merwe et at. (1965) in South Africa. Reports so far available provide very little evidence regarding its toxicity in poultry and other species. Mold-damaged commodities, principally wheat and corn, have always been regarded as harmless and acceptable for use in animal feeds. This use has been a common practice in underdeveloped countries and to some extent in the rest of the world also. Recent developments indicate that the seriousness of mycotoxins must be recognized.

Library of Congress Subject Headings

Poultry -- Feeding and feeds

Toxins

Chickens -- Feeding and feeds

South Dakota State University Theses

Format

application/pdf

Number of Pages

57

Publisher

South Dakota State University

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