Effect of using mycotoxin-detoxifying agents in dairy cattle feed on natural whey starter biodiversity

Natural whey cultures (NWC) are undefined mul-tiple-strain bacterial starter communities that can be affected by even small changes along the entire dairy chain. We applied a multidisciplinary approach to in-vestigate how the addition of 2 mycotoxin-detoxifying agents [sodium smectite and ligno cellulose-based ma-terial (B1); leonardite and betaine (B2)] to cow diets modified the microbiota of the NWC in manufacture of a Grana-like cheese. Microbiological and flow cytom-etry analyses showed that the content and viability of lactic acid bacteria (LAB) and the total whey micro -biota were not affected by the detoxifying agents, and Streptococcus thermophilus, Lactobacillus helveticus, and Limosilactobacillus fermentum were the dominant taxa. Random amplified polymorphic DNA-PCR fin-gerprinting and metagenomic analysis highlighted dif-ferences in the bacterial community of the NWC and in the relative abundance of Bacteroidetes that increased when B1 and B2 were included in the diet. Two of 6 St. thermophilus biotypes were detected only in control samples; conversely, none of the Lb. helveticus biotypes found in control samples were isolated from B1 and B2. In vitro tests showed that the 2 binders did not significantly affect the development of St. thermophilus, but they stimulated the growth of Lb. helveticus strains recovered only from B1 and B2 NWC. The addition of binders in cow feed can affect the LAB biotypes present in NWC.