A review of the effect of feed-borne mycotoxins on pig health and reproduction

摘要

Mycotoxins are secondary metabolites of fungi, diverse in composition and ubiquitous in nature. A given mycotoxin can be produced by more than one species of fungi and individual specie of fungi can produce multiple mycotoxins. Grains, fruits and vegetables can be contaminated with mycotoxins pre-harvest and concentrations can rise with poor storage conditions post-harvest. Pigs are one of the most susceptible species to feed-borne mycotoxins. Aflatoxins inhibit DNA, RNA, and protein synthesis and are recognized as being among the most potently carcinogenic compounds known. The target organs of aflatoxins are liver, the immune system and kidney. Ochratoxin A is a nephrotoxic mycotoxin. Unlike other mycotoxins that are rapidly eliminated from the body by urine or bile, ochratoxin is slowly liberated, retained by the body for up to one month post exposure. The trichothecenes are a large family of chemically-related compounds. The most abundant trichothecene is DON and pigs are very sensitive to DON-contaminated feeds. DON is an inhibitor of DNA, RNA, and protein synthesis. Manifestations of toxicity include reductions in feed intake, emesis, delay of growth, immunosuppression and an increase in the frequency of stillborn piglets. Zearalenone is a very important Fusarium mycotoxin in pig production. Zearalenone binds to the nuclear receptor of estrogens in the reproductive tract eliciting an estrogenic response. Most common effects of zearalenone are reproductive disorders including infertility, small litters, small pigs, deformed pigs, juvenile hyperestrogenism, and fetal absorptions. Young gilts are more affected by zearalenone than older dams. Fumonisins cause pulmonary edema in swine and also have toxic effects on liver and the immune system. Given the sensitivity of pigs to feed-borne mycotoxins, contaminated feedstuffs should be fed only with caution.