NUTRITION
PIH-129
pork industry handbook
PURDUE UNIVERSITY COOPERATIVE EXTENSION SERVICE • WEST LAFAYETTE, INDIANA
Mycotoxins and Swine Performance
Authors
Mark A. Diekman, Purdue University
M. Terry Coffey, Rose Hill, North Carolina
E. Dale Purkhiser, Michigan State University
David E. Reeves, University of Georgia
Les G. Young, University of Guelph
Reviewers
William L. Flowers, North Carolina State University
Duane Miksch, University of Kentucky
Donald H. Scott, Purdue University
Trevor K. Smith, University of Guelph
Fungi
Plants and animals may serve as excellent hosts for many fungi. Spores from fungi (molds) are primarily spread by water and air and come into contact with plants in the field or with grain in storage facilities. Factors that influence the degree of fungal infestation in grain are moisture, temperature and availability of oxygen. Other factors such as insect population, physical condition of grain or susceptibility of certain grain hybrids will also influence whether fungal proliferation will occur under a given set of environmental conditions.

In general, the livestock consumption of feedstuffs containing fungi is not toxic. Most fungal-infected grain is not toxic because toxin-producing species of fungi must compete with nontoxic species to grow; only a small portion of the fungal species produces toxins; and suitable environmental conditions for fungal growth may be different from the conditions suitable for toxin production. Quality of the grain can be reduced by fungal infestations, but most problems with livestock consuming fungal-infested grain result from consumption of mycotoxins produced by fungi.

Mycotoxins
Mycotoxins are toxins produced by fungi on or in grain or feedstuffs when conditions are favorable for their development. Fungi that produce mycotoxins of economic importance to pork producers are Aspergillus, Penicillium, Claviceps and Fusarium. These fungi produce the following mycotoxins: aflatoxins, ochratoxins, ergots, trichothecenes and resorcylic acid lactones (Table 1).

Aflatoxins. Aflatoxins are produced by Aspergillus flavus. This fungus can germinate at lower moisture levels of 15% to 17%, but infection and growth require higher moistures. Aflatoxin production appears to be higher at grain moisture levels of 22% to 26% and temperatures of 82° to 90° F. Conditions for growth are ideal when temperatures remain high both day
and night, but growth decreases dramatically at temperatures above 95°F. Although Aspergillus flavus is abundant in the southeastern United States, drought-stressed com in Indiana and Illinois in 1978, 1983, 1988 and 1991 contained aflatoxin in scattered fields.

Table 1. Feedstuffs that support growth of various fungi, the genera and species of fungi commonly found, and the family of mycotoxins and toxins that are known to impair performance of swine.
Feedstuffs	Fungi Genera/ Species	Mycotoxins Family/ Toxins
Corn, Wheat Rice, Barley Oats, Rye Milk Blood Meal	Aspergillus flavus parasiticus nomius ochraceus	Aflatoxins Ochratoxin Ochratoxin A
Stored Corn, Wheat, Barley	Penicillium viridicatum	Ochratoxin Citrinin
Rye, Wheat Barley	Claviceps purpurea	Ergot
Corn Wheat, Barley	Fusarium graminearum	Trichothecenes Deoxynivalenol
Mixed Feed		Diacetoxyscirpenol Diacetylnivalenol Nivalenol T-2 Toxin Resorcylic acid lactones Zearalenone
	moniliforme	Fumonisin B 1, B2
Cooperative Extension Work in Agriculture and Home Economics. State of Indiana, Purdue University and U.S. Department of Agriculture Cooperating. H. A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the Acts of May 8 and June 30, 1914. We adhere to the policy that all persons shall have equal opportunity and access to our programs and facilities.