septicemia/toxemia and depression in egg production brought about by heat stress (Ward 2002). In practice, feeds contaminated with mycotoxins increase the requirements for fat-soluble and other vitamins (e.g., biotin, folacin and possibly others), and therefore supplementation should be increased above NRC and ARC minimum requirements. Apart from these fat-soluble vitamins, additions of folacin will also improve performance in pigs fed moldy grain (Purser 1981) and additions of biotin will do the same for pigs given feeds containing certain molds (Cunha 1984). Vitamin supplementation above requirements has been shown to be required for optimum immune responses (Ellis and Vorhies 1976; Cunha 1985).