Effects of 3 sequestering agents on milk aflatoxin M1 concentration and the performance and immune status of dairy cows fed diets artificially contaminated with aflatoxin B1

Abstract

This study examined whether adding 3 mycotoxin-sequestering agents to diets contaminated with aflatoxin B1 (AFB1) would reduce milk aflatoxin M1 (AFM1) concentration, and improve the performance and alter immune status of dairy cows. Fifteen lactating dairy cows were used in an experiment with an incomplete crossover design including four 28-d periods. Treatments included a control diet (C), a toxin diet (T; 1,725µg of AFB1/head per day; 75µg/kg), and diets containing the toxin and 20g/head per day of a proprietary mixture of Saccharomyces cerevisiae fermentation product containing a low (SEQ1) or high (SEQ2) dose of a chlorophyll-based additive, or a low dose of the chlorophyll-based additive and sodium bentonite clay (SEQ3). Sequestering agents were top-dressed on the total mixed ration (TMR) daily in each period, and AFB1 was dosed orally in gelatin capsules before the TMR was fed on d 21 to 25. Milk was sampled twice daily on d 20 to 28 and plasma was sampled on d 20 and 25. Sequestering agents did not affect milk AFM1 concentration during the toxin-dosing period. However, after AFB1 was withdrawn, the sequestering agents reduced the time required (24 vs. 48h) to reduce the milk AFM1 concentration below the Food and Drug Administration action level of 0.5µg/kg. Feeding T instead of C tended to reduce milk and fat-corrected milk yields, but feeding SEQ1 prevented these effects. Red blood cell count and hemoglobin concentration were reduced by feeding T instead of C, but not by feeding SEQ1, SEQ2, or SEQ3. The mean fluorescence intensity of antibody staining for 2 leukocyte adhesion molecules, L-selectin (CD62L) and β-integrin (CD18), tended to be greatest when SEQ1 and SEQ3 were fed. Plasma acid-soluble protein concentration was decreased by feeding SEQ1, SEQ2, and SEQ3 instead of T. Sequestering agents had no effect on milk AFM1 concentration, but they reduced the time required to reduce milk AFM1 concentration to a safe level after withdrawal of AFB1 from the diet. Only SEQ1 prevented the adverse effects of AFB1 on milk and fat-corrected milk yields.

Feed additives containing sequestrant clay minerals and inactivated yeast reduce aflatoxin excretion in milk of dairy cows

“…These results suggest that TN and UP did not alter metabolism of absorbed AF to AFM 1 , nor its transfer into, and secretion from, the mammary glands but rather reduced uptake from the gut. This is in agreement with the similar clearance of AFM 1 in the presence or absence of a mycotoxin-sequestering agent found by Queiroz et al (2012) but is in contrast to the study of Ogunade et al (2016), who reported that 3 mycotoxin-sequestering agents evaluated did not reduce AFM 1 concentrations in milk during the dosing period but hastened their decline postdosing.…”

“…As expected, cows fed AF secreted substantial quantities of AFM 1 into their milk. Concentrations of AFM 1 in milk were consistent with those reported by Kutz et al (2009), who also fed AF at about 100 μg/kg of DM, but were markedly higher than those reported by others (Queiroz et al, 2012;Ogunade et al, 2016), who fed about 75 μg of AF/kg of DM, indicating a large difference in absorption, probably due in part to concentrations of AF fed. Inclusion of either TN or UP in the diet significantly reduced (P < 0.01) the concentration and mass of AFM 1 secreted in milk by 50 to 60%, relative to cows on PC treatment, and no statistical difference was observed between TN and UP.…”

“…Both of these variables were significantly affected by time and time by treatment interactions ( Table 2). As shown in Figure 1, concentration and mass of AFM 1 in milk decreased rapidly after withdrawal of AF from diets, as reported previously Queiroz et al, 2012;Ogunade et al, 2016). For TN and UP, concentrations dropped below the FDA limit of 0.5 μg/ kg of milk within 24 h (d 8) and approached 0 μg/kg of milk by 48 h (d 9), whereas concentration and mass in PC appeared to decline more rapidly but still required 1 d more than TN and UP to drop below the FDA limit (d 9) or approach zero (d 10).…”

“…For example, supplementation of an AF adsorbent to dairy cows challenged with AF did not affect mammary, liver, or immune function, but altered rumen characteristics in the presence or absence of dietary AF (Xiong et al, 2015). In contrast, feeding AF tended to reduce milk fat yield and alter some indicators of immune status, but effects of supplemental adsorbents on those variables and AFM 1 concentrations in milk were inconsistent (Queiroz et al, 2012;Ogunade et al, 2016).…”

“…These adsorbents bind to dietary AFB 1 , making it unavailable for absorption, and thereby reducing formation of AFM 1 and its secretion into milk Gallo and Masoero, 2010;Queiroz et al, 2012). The ability of these compounds to reduce AFM 1 in milk is related both to level of inclusion of the products in the diet and to the concentration of AF that is supplied to the cows (Diaz et al, 2004;Kutz et al, 2009;Ogunade et al, 2016). Moreover, there are indications of effects of AFB 1 or the adsorbents, themselves, on milk production, rumen fermentation, and immune status, but responses have been inconsistent.…”