Browsing by Subject "Aflatoxins"
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Item Conversions of versiconal acetate and hemiacetals in cell-free extracts from Aspergillus parasiticus(Texas Tech University, 1989-08) Chung, Chang HoNot availableItem Diet modified aflatoxicosis(Texas Tech University, 1978-05) Haesemeyer, James FrederickNot availableItem Safety and efficacy of NovaSil clay as a dietary supplement to prevent aflatoxicosis(Texas A&M University, 2006-04-12) Afriyie-Gyawu, EvansIt is well documented that aflatoxin contamination in foods presents significant economic and public health burdens worldwide. Aflatoxins, particularly aflatoxin B1 (AFB1), have been implicated in the etiology of disease and death in many parts of the world, necessitating research initiatives for intervention strategies designed to diminish biological exposure. Calcium montmorillonite clays (e.g. NovaSil Plus, NSP) have been found to tightly bind and inactivate aflatoxins in the gastrointestinal tract of multiple animal species. In the future, the hypothesis is that this strategy may also be appropriate for humans. Thus, the overall research goal was to investigate NSP suitability for human use through in vitro characterization followed by in vivo evaluation of NSP-AFB1 sorption and most importantly, safety of the clay. The first objective was to characterize the in vitro and in vivo sorption efficiency of NSP-AFB1 sorption and determine potential interactions with vitamin A (VA). Isothermal analysis suggested that NSP binds AFB1 with high capacity, affinity, and specificity in aqueous solution and further indicated that NSP does not appear to interact with VA. Subsequent short-term studies in Sprague-Dawley (S-D) rats and broiler chicks indicated that dietary inclusion of NSP (0.25%) significantly reduced AFB1 bioavailability without exerting overt toxicity. The second objective was to evaluate potential adverse effects of chronic ingestion of dietary NSP using male and female S-D rats in the absence of aflatoxins. Although statistically significant changes to a few parameters were noted, the differences did not appear to be NSP- or dose-dependent, suggesting that NSP at dietary inclusion levels as great as 2.0% (w/w) does not produce overt toxicity. Thus, this information increases the feasibility for using NSP in human trials in populations at high risk for aflatoxicosis. The third objective was to establish representative baseline data on human exposure to aflatoxins by collecting and quantifying urinary AFM1 in volunteers living in four separate communities in Ejura district of Ghana. Results revealed that urinary AFM1 in the study population was substantially high (mean = 1,850.86 ?? 274.59 pg/mg creatinine), indicating that this particular population was highly exposed to aflatoxins and could be used for future intervention trials.Item Significance of aflatoxin exposure to northern bobwhite from native and supplemental feeds(Texas Tech University, 1999-05) Oberheu, Deanna ThompsonMycotoxins are toxic metabolites produced by various genera of fungi, such as Aspergillus, Fusarium, and Penicillium. Aflatoxins, produced primarily by A. flavus and A. parasiticus, are the most commonly occurring and widely known mycotoxins. Aflatoxins are carcinogenic, hepatotoxic, teratogenic, and immunosuppressive. Aflatoxins can affect a wide variety of animals, including fish, rodents, waterfowl, poultry, swine, and cattle. The significance of the problem for wildlife, however, is largely unknown. Data concerning impacts of aflatoxin on wildlife in the field are limited. Fifty-one percent of com used for feeding deer in North and South Carolina contained AF with concentrations as high as 750 ppb (Fischer et al. 1995). Couvillion et al. (1991) investigated the mycotoxin production dynamics of waste com. Corn left in the field after harvest was found to contain 5 to 5,000 ppb AF. Comparison of these levels to those used in laboratory experiments suggests many possible detrimental impacts on wildlife. Large waterfowl die-offs occurred in two separate areas of Texas in the 1977-1978 wintering season; approximately 500 geese and 7,000 ducks succumbed to aflatoxicosis (Robinson et al. 1982).