title: Bioavailability of aflatoxin B1and ochratoxin A, but not fumonisin B1or deoxynivalenol, is increased in starch-induced low ruminal pH in nonlactating dairy cows.
abstract: High-production dairy and beef systems require diets rich in starch. This practice may induce ruminal acidosis and also increase exposure to mycotoxins because starches in starch-rich diets are the main vehicles of mycotoxin contamination. The aim of this study was to investigate the effects of low ruminal pH on the bioavailability of 4 major mycotoxins [i.e., aflatoxin B1(AFB1), ochratoxin A (OTA), deoxynivalenol (DON), and fumonisin B1(FB1)]. Eight nonlactating dairy cows fitted with rumen cannulas were used in a double crossover experiment. The trial was divided into 4 periods with 2 periods per crossover. Cows were divided into 2 groups receiving a low (15% dry matter basis) and high-starch diet (30.8%) with and without live yeast supplementation (1×1010cfu per cow) in the first and second crossover, respectively. At the end of each period, cows received a single dose of mycotoxin-contaminated feed containing 0.05, 0.2, 0.24, and 0.56mg of AFB1, OTA, DON, and FB1 per kg of feed, respectively. The fecal and urinary excretion of mycotoxins and their metabolites was monitored for up to 48h postdosing. As expected, ruminal pH decreased in cows fed the high-starch diet. The high-starch diet increased the bioavailability of OTA and AFB1. Urinary excretion of OTA 24h after mycotoxin administration increased 3-fold in the high-starch diet, correlated with lower fecal excretion. Similarly, a decrease in fecal excretion of AFB1 was accompanied by an increase in urinary excretion of its major metabolite, aflatoxin M1, 48h after mycotoxin administration. In contrast to AFB1 and OTA, the bioavailability of DON and FB1 remained unchanged. Yeast supplementation had no effect on the excretion balance of these 2 mycotoxins. In conclusion, these results show that high-starch diets increased the bioavailability of OTA and AFB1, most probably through the lowering effect on ruminal pH. This greater bioavailability potentially increases the toxic effects of these mycotoxins.
authors: UMRH, INRA, Vetagro Sup, 63122 Saint-Genès-Champanelle, France; Department of Animal Science, State Polytechnic Jember, Jember, Indonesia, 68121.
authors: D
authors: D
authors: Pantaya
authors: UMRH, INRA, Vetagro Sup, 63122 Saint-Genès-Champanelle, France.
authors: D P
authors: DP
authors: Morgavi
authors: UMRH, INRA, Vetagro Sup, 63122 Saint-Genès-Champanelle, France.
authors: M
authors: M
authors: Silberberg
authors: Lallemand Animal Nutrition, 31702 Blagnac Cedex, France; Unité de Microbiologie, INRA, 63122 Saint-Genès-Champanelle, France.
authors: F
authors: F
authors: Chaucheyras-Durand
authors: UMRH, INRA, Vetagro Sup, 63122 Saint-Genès-Champanelle, France.
authors: C
authors: C
authors: Martin
authors: Faculty of Animal Science, Bogor Agricultural University, Bogor, Indonesia, 16680.
authors: Suryahadi
authors: Faculty of Animal Science, Bogor Agricultural University, Bogor, Indonesia, 16680.
authors: K G
authors: KG
authors: Wiryawan
authors: UMRH, INRA, Vetagro Sup, 63122 Saint-Genès-Champanelle, France. Electronic address: abdelhamid.boudra@clermont.inra.fr.
authors: H
authors: H
authors: Boudra
mesh_terms: D016604:Aflatoxin B1 / Q000378:metabolism*; D016607:Aflatoxin M1 / Q000378:metabolism; D000818:Animals; D001682:Biological Availability; D002417:Cattle; D004032:Diet / Q000662:veterinary; D005260:Female; D006863:Hydrogen-Ion Concentration; D009793:Ochratoxins / Q000378:metabolism*; D012417:Rumen / Q000737:chemistry / Q000378:metabolism; D013213:Starch / Q000378:metabolism*
chemical_list: D009793:Ochratoxins; C025589:ochratoxin A; D016607:Aflatoxin M1; D013213:Starch; D016604:Aflatoxin B1
keywords: dairy cow; live yeast supplementation; low ruminal pH; mycotoxin