ORIGINAL ARTICLE Effect of dietary supplementation of bentonite and yeast cell wall on serum endotoxin, inflammatory parameters, serum and milk aflatoxin in high-producing dairy cows during the transition period Ahmadreza Mirzaei 1 & Ali Hajimohammadi 1 & Khalil Badiei 1 & Mehrdad Pourjafar 1 & Abbas Ali Naserian 2 & Seyed Amin Razavi 1 Received: 5 March 2019 /Accepted: 25 October 2019 # Springer-Verlag London Ltd., part of Springer Nature 2019 Abstract Twenty-four Holstein cows were randomly allocated to four equal experimental groups containing a control (n = 6) and three treatment (n = 6) groups. Experimental animals were selected according to their average milk yield, weight, and body condition score. The experimental groups received basal diet + Saccharomyces Cerevisiae cell wall (SCW) (group 1), basal diet + bentonite + SCW (group 2), basal diet + bentonite (group 3), and basal diet (control), on a dry matter basis (group 4). Blood samples were taken 4, 3, and 1 week prior to and 1 and 3 weeks following parturition. Serum concentrations of haptoglobin (Hp), serum amyloid A (SAA), lipopolysaccharide (LPS), and concentration of aflatoxin B1 in ration and M1 in milk and blood were determined during the transition period. The results showed that LPS concentration in blood was in the normal range in all groups. The acute-phase proteins (Hp and SAA) were in the normal range as well. The concentration of aflatoxin M1 in the serum of the control group was higher than other groups, yet lower in the group receiving toxin binders (p < 0.05). The mean aflatoxin M1 concentration in milk was the lowest in the group receiving SCW (p < 0.05). Similarly, the concentration of aflatoxin M1 in milk was the highest in the control group (p < 0.05). The study also showed that the levels of endotoxin in ration of different groups resulted from our experimental diet were not high enough to stimulate APP response. It was further observed that SCW might be able to reduce the level of aflatoxin in serum and milk. The results obtained from our study may lead to a better understanding of using dietary supplements, such as bentonite and yeast cell wall, during the transitional period. Moreover, the study may contribute to our knowledge on simultaneous LPS and toxin binders for providing more safe food during the transition period in cattle. Keywords Endotoxin binder . Dairy cow . Acute phase response . Aflatoxin . Transition period Introduction Cattle population in Iran is 7.9 million, of which 49.5, 43.6, and 10.51% are indigenous, cross-breed, and registered, re- spectively (Ebrahimi Hoseinzadeh et al. 2015). Dairy produc- tion has undergone significant and considerable structural changes over the past two decades due to the production of larger herds (FAO 1993). Metabolic diseases mostly occur in dairy cows, particularly in periods extending from calving to the peak of lactation, over which period 25–50% of diseases occur. This important stage can affect the reproductive perfor- mance of the cattle, and nutrition is the most challenging problem during this period of dairy cattle life cycle (Cook and Nordlund 2004; Grummer et al. 2004; Roche et al. 2013). It is obvious that correct management in this period have a significant effect on milk quality and quantity. Several studies have tried to find out the risk factors associated with the occurrence of health problems during the transition period (Mallard et al. 1998; Trevisi et al. 2012). The ability of dairy cattle to restraint the establishment of disease during the transition period is related to the competence of immune sys- tem; also, environmental and management factors can be ma- nipulated to ease this period (Sordillo 2016). Strategies to * Ali Hajimohammadi hajimohammadi@shirazu.ac.ir; ali.hadjimohammadi@gmail.com 1 Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz 7144169155, Iran 2 Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran Comparative Clinical Pathology https://doi.org/10.1007/s00580-019-03074-y