Abstract #T153

# T153
A postbiotic from Aspergillus oryzae decreased the inflammation response of lactating dairy cows exposed to heat stress.
J. Kaufman*1, H. Bailey1, P. De Toledo Shimoda1, F. Bargo2,3, I. Ipharraguerre4, G. Pighetti1, A. Ríus1, 1University of Tennessee, Knoxville, TN, 2BioZyme Inc, St. Joseph, MO, 3Universidad de Buenos Aires, Buenos Aires, Argentina, 4University of Kiel, Kiel, Germany.

The objective of this study was to evaluate the effect of a postbiotic additive from Aspergillus oryzae (AO) on the inflammation response in lactating dairy cows exposed to heat stress. Thirty-six Holstein cows (105 ± 23 SD days in milk, 714 ± 23 kg body weight) were used in a completely randomized design and randomly assigned to 1 of 3 treatments for 36 d: 0 g/d (control; CTL), 3 g/d (low), and 6 g/d (medium) of the AO postbiotic (Biozyme Inc., St. Joseph, MO). A 41% forage and 59% concentrate TMR (18.1% CP, 33.0% NDF, 1.61 Mcal/kg NEL) was individually fed twice daily, and AO was top-dressed twice daily. Cows experienced warm climate during June and July 2018. Cows were provided with heat abatement of fans and misters from d 1 to 10 (period 1) and without heat abatement from d 11 to 36 (period 2). Acute phase proteins [haptoglobin, serum amyloid A, and lipopolysaccharide (LPS) binding protein] were determined from plasma collected on d 11 and 35. On d 36, 2 whole blood samples were collected for an ex-vivo challenge with or without LPS (5 μg/μL). The expression of IL-1β, IL-6, and TNF-α was measured using qPCR. Three analyses were conducted on cytokine expression: 1) no LPS stimulation, 2) LPS stimulation, and 3) ratio of LPS to no LPS stimulation. Mild heat stress was attained in period 1, whereas heat stress intensity was increased in period 2 (temperature-humidity index = 74.6 ± 2.4 and 77.3 ± 4.2 [mean ± SD]). In period 1, AO quadratically decreased (P = 0.03) LPS binding protein concentrations in plasma by 25.7%. In period 2, AO quadratically decreased (P = 0.01) serum amyloid A concentrations in plasma by 65.6% and tended to quadratically decrease (P ≤ 0.10) haptoglobin and LPS binding protein concentrations by 35.4 and 23.3%, respectively. From the ex vivo LPS challenge, AO linearly decreased (P = 0.02) the IL-6 expression ratio (LPS to no LPS stimulation) by 65.6%. In summary, AO decreased markers of inflammation and cytokine production in cows exposed to heat stress. These findings may be associated with improvements of health in cows exposed to heat-stress.

Key Words: heat stress, inflammation, prebiotic