Fifteen primiparous crossbred dairy cows that were 114±14d in milk and weighed 533±56kg were used in a replicated 5×5 Latin square to test the efficacy of a calcium montmorillonite clay, NovaSil Plus (NSP; BASF Corp., Ludwigshaven, Germany), for the reduction of aflatoxin (AF) metabolite (AFM1) in milk and the effect of NSP on milk composition. Cows were housed in a freestall barn, fed once a day and milked twice a day. The experiment consisted of five 14-d periods: d 1 through 7 were considered for data collection, and d 8 through 14 were considered a wash-out phase. In each period, cows were randomly assigned to 1 of 5 dietary treatments: (1) control (CON), consisting of a basal total mixed ration (TMR); (2) high-dose NSP diet (NSP-1%), consisting of TMR plus 230 g of NSP; (3) aflatoxin diet (AFD), consisting of the TMR plus AF challenge; (4) low-dose NSP with AF (NSP-0.5%+AFD), composed of TMR plus 115 g of NSP and AF challenge; and (5) high-dose NSP with AF (NSP-1%+AFD), consisting of TMR plus 230 g of NSP and AF challenge. The AF challenge consisted of top dressing a daily dose of 100 µg/kg estimated dry matter intake (DMI); similarly, NSP was fed at 1.0 or 0.5% of estimated DMI. Milk yield and DMI were similar across treatments averaging 21.1±1.33 kg/d and 19.7±0.56 kg/d, respectively. Concentration of milk fat, protein, and lactose were similar across treatments with averages of 4.91±0.20%, 3.85±0.10%, and 4.70±0.06%, respectively. Concentration of vitamin A averaged 0.28±0.03 µg/mL and riboflavin concentration averaged 1.57±0.13 µg/mL across treatments. The concentration of minerals in milk were similar for all treatments. Cows fed CON and NSP-1% yielded the lowest concentration of AFM1 in milk with 0.03 and 0.01±0.06 µg/L. Addition of NSP reduced milk AFM1 from 1.10±0.06 µg/L with the AF diet to 0.58 and 0.32±0.06 µg/L with the NSP-0.5%+AF and NSP-1%+AF diets, respectively. Excretion of AFM1 was reduced by NSP; mean values were 24.38, 11.86, 7.38, 0.64, and 0.23, ± 1.71 µg/d, for AFD, NSP-0.5%+AFD, NSP-1%+AFD, NSP-1%, and CON, respectively. More specifically, 1.07±0.08% of the daily AF intake was transferred to the milk of cows consuming the AFD, whereas the AF transfer rates in milk from cows that consumed the NSP-0.5%+AFD and NSP-1%+AFD were 0.52 and 0.32±0.08%. Results from this research demonstrate that feeding NSP to lactating cows is an effective method to reduce the transfer and excretion of AFM1 in milk with no negative effects on dry matter intake, milk production, and composition.

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Previously, a calcium montmorillonite clay (NovaSil) included in the diet of animals has been shown to bind aflatoxin B1 (AfB1) and reduce the symptoms of aflatoxicosis. To investigate and improve the capacity and efficacy of clay-based materials as aflatoxin sorbents, we developed and tested calcium and sodium montmorillonite clays amended with nutrients including l-carnitine and choline. Also, we determined the sorption of AfB1 by isothermal analysis and tested the ability of these amended sorbents to protect adult hydra from AfB1 toxicity. The results showed that exchanging montmorillonite clays with l-carnitine and choline inhibited swelling of the clays and increased the sorption capacity and efficacy of clay surfaces for AfB1. Results from dehydroxylated and heat-collapsed clays suggested that AfB1 was primarily adsorbed in the clay interlayer, as predicted from thermodynamic calculations and computational modeling. The hydra bioassay further indicated that the modified clays can significantly protect adult hydra from AfB1 with as low as 0.005% clay inclusion. This enterosorbent therapy may also be applied to screen hazardous chemicals such as pesticides and PAHs based on similar sorption mechanisms. Taken together, enterosorbent therapy could be delivered in nutritional supplements, foods that are vulnerable to aflatoxin contamination, flavored liquids and animal feeds during emergencies and outbreaks of acute aflatoxicosis, and as a screening model for hazardous environmental chemicals.

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