Location: Livestock Behavior ResearchTitle: In vivo response of peripheral leukocytes to oral delivery of probiotics in neonatal dairy calves
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/2018
Publication Date: 12/1/2018
Citation: Eicher, S.D., Chitko-McKown, C.G., McDaneld, T.G., Bryan, K. 2018. In vivo response of peripheral leukocytes to oral delivery of probiotics in neonatal dairy calves [abstract]. Conference of Research Workers in Animal Diseases. P090.
Technical Abstract: A few studies report improved respiratory health when feeding cattle for enteric health. The objective of this research was to determine the peripheral blood response to oral probiotics for neonatal calves to compare with respiratory responses. In this report we present only peripheral immune changes of that study. Twenty dairy calves were assigned to receive either milk replacer without or with probiotics (0.5 g/d of Bovamine, Chrs. Hansen) daily beginning 2 days after birth (n = 10/treatment). Blood was collected into EDTA (differential counts) and ACD (flow cytometry) vacuum tubes on d 7 after initiating probiotics. Cells were isolated by hypotonic lysis and aliquoted into tubes to receive; no antibody, bovine a-CD14, bovine a-CD205, bovine a-CD11b, bovine a-CD3, bovine a-CD4, bovine a-CD8, and bovine a-CD3. E. coli bioparticles were opsonized and used to determine phagocytosis and oxidative burst. A treatment by day (trt * d) effect (P = 0.01) was found for neutrophils, such that on d 21 probiotic fed calves had a greater % neutrophils. Basophils had trt * d effects for both counts and percentages, with greater counts and percentages for the probiotic fed calves on d 42 (P = 0.02 and 0.01, respectively). By d 7 calves on probiotic had fewer CD4 (P = 0.002) and CD14 (P = 0.02) positive cells. Mean fluorescence of calves on probiotics was less for CD8 (P = 0.03), CD3 (P = 0.02), CD205 (P = 0.03), and for oxidative burst (P = 0.01). Phagocytosis percent positive cells and mean fluorescence tended to be greater for the calves on probiotics (P = 0.09 and P = 0.08, respectively). While greater neutrophil counts suggest activation, fewer CD4 and CD14 positive cells suggest a quiescent immune system. Reduced fluorescence without more positive cells, suggests less stimulation of those cells. Additionally, the probiotic calves tended to have a greater capacity to recognize and to engulf the E. coli bioparticles. Additional data up to d 49 and qRT-PCR from each of the sample days may help determine whether the probiotic calves’ cells were just quiescent or fatigued.