Managing Mycotoxin-Contaminated Grain In Hog Feeding

Pigs consuming mycotoxins above their tolerance level will face health and reproductive problems.  ( National Pork Board )

Heavy rains this summer and fall have caused concerns about the development of fungi molds in grain. Some fungi molds in grain can produce harmful compounds called mycotoxins. Pigs consuming mycotoxins above their tolerance level will face health and reproductive problems. 

There are no known methods of detoxifying mycotoxins in contaminated grain. Thus, it’s essential to prevent mycotoxin production by properly storing grains. There are a few ways to reduce the harmful effects of mycotoxins on swine health and performance.

Feed possibly contaminated feed or grain to a small number of "test" animals and closely watch them for signs of mycotoxin toxicity.

Prepubertal gilts are often good "test" animals if you suspect the feed contains zearalenone (swollen vulvas) or vomitoxin (reduced feed intake).

Collect samples of the suspect grain and send them to a commercial analytical laboratory to determine mycotoxin levels. Once you know the levels, you can blend contaminated grain with good quality grain to lessen mycotoxin levels below the critical levels.

Try marketing the grain to cattle (not dairy cows if aflatoxin contaminated) or sheep producers. Ruminants are less sensitive to mycotoxin toxicity than pigs and poultry. You can then purchase uncontaminated grain to avoid health and performance problems.

Consider putting grain through a grain cleaner to remove fines. Broken and damaged kernels are generally highest in mycotoxin contamination because the seeds natural protection has been broken. Avoid feeding grain screenings and fines to swine.

Sodium bentonite and a commercial feed additive called NovasilTM can reduce the harmful health and performance effects of pigs fed aflatoxin-contaminated feeds. They may also partially lessen the harmful effects of other mycotoxins.

Dry and aerate grains to adequate moisture levels before storing to prevent further mold growth and mycotoxin production. Consider adding commercially available additives or organic acids (propionic, fumaric, citric) to prevent mold growth.

Avoid feeding mycotoxin-contaminated grain to the breeding herd and young pigs. Grow-finish pigs fed for slaughter tolerate mycotoxin-contaminated grain best. Combinations of certain mycotoxins may harm performance more than normally expected for each of the mycotoxin levels evaluated individually. Thus, you should consider this when evaluating feeds. Table 1 shows the mycotoxin tolerance levels of pigs and effects of toxicity.

Mycotoxin

Maximum tolerable level

Comments

Aflatoxins (B1, B2, G1, G2)

< 20 ppb for human use, dairy feed, feed for immature animals < 100 ppb for breeding swine < 200 ppb for finishing swine (>120 lbs body weight)

Carcinogenic (can cause cancer) Immunosuppressant (weakens the immune system) Acute signs: Anorexia Depression Ataxia (lose body control) Epistasis Chronic signs: Reduced feed efficiency Reduced milk production Icterus (yellowing of skin) Decreased appetite

Zearalenone

< 1 ppm for young growing pigs < 2 ppm for breeding herd < 3 ppm for finishing pigs and young and old boars

Estrogenic effects: Swollen vulvas, vaginal or rectal prolapses in pre-pubertal gilts Enlarged uterus Swollen or twisted uterus Shrunken ovaries In boars: Testes atrophy (waste away) Enlarged mammary glands Decreased fertility

Deoxynivalenol (vomitoxin)

< 5 ppm on grain and grain by-products. Vomitoxin contaminated feedstuffs shouldn’t exceed 20% of the diet (< 1 ppm in complete feeds).

Reduced feed intake and weight gain are inversely proportional to concentration of vomitoxin. As one increases, the other decreases High levels cause feed refusal and vomiting

T-2 toxin

< 1 ppm

Strong immunosuppressive agent that directly affects immune cells and modifies immune response as a consequence of other tissue damage Frequent defecation, vomiting, weight loss and feed refusal

Fumonisin

Not established

Carcinogenic in laboratory tests using rats Associated with pulmonary edema in pigs

Ochratoxin

< 200 ppb

Ochratoxin A is most common and potent. Reduced growth Reduced feed efficiency Increased mortality Liver and kidney damage

Ergot

< 200 ppb

Vertigo Staggers Convulsions Temporary posterior paralysis Eventual death Decreased peripheral blood supply Reduced growth tail loss Reduced reproductive efficiency of sows

 
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