Efficacy of Bacillus subtilis ANSB060 Biodegradation Product for the Reduction of the Milk Aflatoxin M₁ Content of Dairy Cows Exposed to Aflatoxin B₁.

Yongpeng Guo,Lihong Zhao,Qiugang Ma,Jianyun Zhang,Chen Wei,Yong Zhang,Cheng Ji

doi:10.3390/toxins11030161

Yongpeng Guo, Lihong Zhao + Show 5 more

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https://doi.org/10.3390/toxins11030161

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Abstract

This study was conducted to determine the effect of Bacillus subtilis ANSB060 biodegradation product (BDP) in reducing the milk aflatoxin M1 (AFM1) content of dairy cows fed a diet contaminated with aflatoxin B1 (AFB1). Twenty-four Chinese Holstein cows (254 ± 19 d in milk; milk production 19.0 ± 1.2 kg d−1) were assigned to three dietary treatments, as follows: (1) control diet (CON), consisting of a basal total mixed ration (TMR); (2) aflatoxin diet (AF), containing CON plus 63 μg of AFB1 kg−1 of diet dry matter; and (3) aflatoxin diet plus BDP (AF + BDP), containing AF plus BDP at 0.2% of diet dry matter. The experiment lasted 12 days, including an AFB1-dosing period from days one to eight, followed by a clearance period from days nine to twelve. Milk samples were collected on days 2, 4, 6, and 8–12, and the plasma was sampled on day 9, before morning feeding. Short-term AFB1 exposure did not affect the milk production and composition. The plasma biochemical indices, except for lactic dehydrogenase (LDH), were also not changed by the AFB1 intake. The plasma LDH level was significantly elevated (p < 0.05) following dietary treatment with AFB1, while no significant difference was observed between the AF + BDP and CON treatments. Adding BDP to the AFB1-contaminaed diet resulted in a significant reduction in AFM1 concentration (483 vs. 665 ng L−1) in the milk, AFM1 excretion (9.14 vs. 12.71 μg d−1), and transfer rate of dietary AFB1 to milk AFM1 (0.76 vs. 1.06%). In conclusion, the addition of BDP could be an alternative method for reducing the dietary AFB1 bioavailability in dairy cows.

Highlights

Aflatoxins (AF) are harmful secondary metabolites mainly produced by Aspergillus flavus and Aspergillus parasiticus fungi
Maki et al [5] and Sulzberger et al [24] found no changes in the milk yield and composition of dairy cows in early to mid-lactation when administrated with aflatoxin B1 (AFB1) at doses of 79 and 100 μg kg−1 in the feed
aflatoxin M1 (AFM1) cleared from the milk of the dairy cows fed a diet contaminated with AFB1 (75 μg kg−1 ) 72 h after withdrawing the toxin. These findings suggested that the clearance of AFM1 from milk after the ending of AFB1 administration is not related to the dietary AFB1 content

Summary

Introduction

Aflatoxins (AF) are harmful secondary metabolites mainly produced by Aspergillus flavus and Aspergillus parasiticus fungi. AFB1 is the most prevalent and toxic, and has been classified as a Group I human carcinogen by the International Agency for Research on Cancer (IARC). After ingestion by livestock animals, AFB1 is partly bio-transformed into aflatoxin M1. (AFM1 ) in the liver by the mitochondrial cytochrome P450 oxidative system, which is secreted into the milk of lactating animals, including dairy cattle. The transfer rate of dietary AFB1 to milk AFM1 mainly depends on the milk yield, and is usually 1%–2% for low-yielding cows (30 kg milk yield per day) and up to ~6% for high-yielding cows (>30 kg milk yield per day) [1]. Milk contamination with AFM1 has attracted worldwide attention because of the high consumption of milk and dairy products by humans, especially children. Considering the health risks associated with the human dietary exposure to AFM1 , more than 60 countries have set strict guidelines for maximum residue level (MRL) of AFM1 in milk [2]

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