The effects of the DFM CLOSTAT® and experimental Salmonella challenge on the microbiome of the ileum in weaned Holstein steer calves

Authors: Broadway, Paul; Carroll, Jeffery - Jeff Carroll; Sanchez, Nicole; CALLAWAY, TODD - University Of Georgia; LAWHON, SARA - Texas A&M University; BRYAN, LAURA - Texas A&M University; GART, ELENA - Texas A&M University; HUGHES, HEATHER - West Texas A & M University; HERGENREDER, JERILYN - Kemin Industries, Inc; ROUNDS, WHITNEY - Kemin Industries, Inc; GRISWOLD, KEN - Kemin Industries, Inc

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 11/21/2017
Publication Date: 3/1/2018
Citation: Broadway, P.R., Carroll, J.A., Sanchez, N.C., Callaway, T.R., Lawhon, S.D., Bryan, L.K., Gart, E.V., Hughes, H., Hergenreder, J.E., Rounds, W., Griswold, K. 2018. The effects of the DFM CLOSTAT® and experimental Salmonella challenge on the microbiome of the ileum in weaned Holstein steer calves. Journal of Animal Science Supplement. 96(Suppl-1):41-42.

Interpretive Summary:

Technical Abstract: Direct Fed Microbials (DFM) are probiotic-type compounds that are utilized in calf feeding operations as novel, non-antibiotic technologies to improve health and performance. The modes of action of most probiotics remain unknown, but their impacts on the microbial ecology of the GI tract may be responsible for positive changes in animal health and performance. Therefore, the objective of this study was to evaluate changes in the microbiome of the ileum of Holstein steer calves supplemented with a DFM comprised of a patented strain of Bacillus subtilus (CLOSTAT®; 13 g/hd/d for 35d: Kemin Industries Des Moines, IA) following an experimental, oral Salmonella challenge. Holstein steer calves (n=40) were assigned to treatments in a 2 x 2 factorial design and either fed CLOSTAT (CLO) or not (CON) and inoculated with Salmonella Typhimurium (SAL; 1.1x 106 CFU) or not (NOSAL) in the calves’ milk replacer. Our lab previously reported CLO supplementation reduced Salmonella in the GI tract and reduced the febrile response in CLO calves following SAL challenge. Upon harvest in the present study, ileum tissue samples were collected and the microflora of each calf was analyzed using Ilumina MiSeq. Diversity was examined for overall richness (OTU), quantified using the Chao 1 richness estimator, and data were examined for richness and evenness distribution amongst distinct taxa using the Shannon Diversity Index. Group differences were analyzed using permutational multivariate analysis of variance. There was no difference in the number of distinct species or genera present within the microbiome between CLO and CON or the interaction of CLO supplementation and SAL inoculation (P>0.20). Inoculation of calves with Salmonella increased species/genera richness (P=0.02) in the ileum. Overall, there was no difference in the Shannon Diversity Index due to CLO (P>0.05), but the diversity was increased with SAL inoculation (P<0.01). However, there was no interaction of CLO and SAL (P>0.05) on any measure of microbial diversity. Similarly, the number of OTU’s were not affected by CLO (P>0.05); however, SAL increased the number of OTU’s (P=0.02) in ileal contents. While positive effects on animal health were observed in SAL calves fed CLO, there was no overall difference in the composition of the microbiome of the ileum. However, SAL administration, as expected, significantly influenced the ileal microbiome of Holstein steer calves. More research is needed to fully elucidate the effects of CLO supplementation on the microbiome of calves in the various compartments of the GI tract.