Supplementing a Saccharomyces cerevisiae fermentation product modulates innate immune function and ameliorates bovine respiratory syncytial virus infection in neonatal calves.

摘要: The objectives of this study were to determine the effects oral supplementation with Saccharomyces cerevisiae fermentation products (SCFP; SmartCare and NutriTek; Diamond V, Cedar Rapids, IA) on immune function bovine respiratory syncytial virus (BRSV) infection in preweaned dairy calves. Twenty-four Holstein × Angus, 1- 2-d-old calves (38.46 ± 0.91 kg initial body weight [BW]) assigned two treatment groups: control or SCFP treated, milk replacer 1 g/d (SmartCare) calf starter top-dressed 5 (NutriTek). consisted one 31-d period. On days 19 21 period, challenged via aerosol inoculation BRSV strain 375. Calves monitored twice daily for clinical signs, including rectal temperature, cough, nasal ocular discharge, respiration effort, lung auscultation. euthanized day 10 postinfection (days 29 31 period) evaluate gross pathology pathogen load. Supplementation did not affect BW (P = 0.762) average gain 0.750), percentages circulating white blood cells < 0.05), phagocytic 0.427 neutrophils P 0.460 monocytes) burst 0.119 0.414 activity by leukocytes either before following infection, serum cortisol concentrations 0.321) after infection. receiving had reduced disease scores compared 0.030), airway neutrophil recruitment 0.002), 0.031), a incidence secondary bacterial shed 0.049) tended toward lower viral loads lungs 0.051). Immune from peripheral SCFP-treated produced increased 0.05) quantities interleukin (IL)-6 tumor necrosis factor-alpha response toll-like receptor stimulation, while bronchoalveolar lavage (BAL) secreted less proinflammatory cytokines same stimuli. Treatment no effect virus-specific T cell responses but resulted 0.045) IL-17 secretion BAL. Supplementing modulates both systemic mucosal may improve outcome an acute