Effects of dietary adsorbent on milk aflatoxin M1 content and the health of lactating dairy cows exposed to long-term aflatoxin B1 challenge

Abstract

The objective of this study was to evaluate the effects of Solis Mos (Novus International Inc., St. Charles, MO) on milk aflatoxin M₁ (AFM1) content, lactation performance, plasma biochemical parameters, and ruminal fermentation in dairy cows exposed to long-term aflatoxin B₁ (AFB1) challenge. Forty dairy cows were grouped according to days in milk (33 ± 7 d; mean ± SD) and milk production (33.9 ± 3.1 kg) and randomly assigned to 1 of 4 treatments: control (no additive), 20 μg of AFB1/kg of diet dry matter (AF), addition of Solis Mos at 0.25% of diet dry matter (SM), and MIX (AF + SM). The experiment lasted 9 wk, including an adaptation period during the first week. Dry matter intake, milk yield, and milk composition were measured on d 6 and 7 of each week. Milk AFM1, plasma biochemical parameters, and ruminal fermentation variables were analyzed on the last days of wk 1 and 9. No differences were observed in dry matter intake, milk yield, percentages of milk protein, milk fat, and lactose, and somatic cell counts across the treatments. Addition of adsorbent in the AFB1-contaminated diet significantly reduced the milk AFM1 concentrations (0.19 vs. 0.13 μg/kg) and transfer rates (1.38 vs. 0.89%). Dairy cows fed an AFB1-contaminated diet had lower superoxide dismutase activity, total antioxidant capacity, glutathione peroxidase, and levels of IgG and IgA, and higher levels of malondialdehyde in the plasma. Inclusion of Solis Mos in the diet increased the plasma superoxide dismutase activity, total antioxidant capacity, and IgG levels, and decreased the malondialdehyde level. Neither AFB1 nor Solis Mos affected the plasma levels of glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, alkaline phosphatase, or IgM. Long-term inclusion of adsorbent Solis Mos in the diet did not affect lactation performance or liver function, but it reduced milk AFM1 concentrations and oxidative stress and improved the immunological condition and ruminal fermentation in lactating dairy cows exposed to long-term AFB1 challenge.

Keywords: adsorbent; aflatoxin; lactation performance; rumen fermentation.