The aim of this study was to evaluate the effects of Saccharomyces cerevisiae fermentation products (SCFP) in the calf starter and milk on ruminal fermentation, gastrointestinal morphology, and microbial community in the first 56 d of life. Thirty Holstein bull calves were randomly assigned to 1 of 3 groups: a texturized calf starter containing 0 (CON), 0.5, or 1% SCFP (XPC, Diamond V, Cedar Rapids, IA) of dry matter from d 4 to 56. In addition, the XPC-supplemented calves were fed with 1 g/d SCFP (SmartCare, Diamond V, Cedar Rapids, IA) in milk from d 2 to 30. All calves were fed 4 L of colostrum within 1 h of birth and were subsequently fed milk twice daily until weaned on d 56. Rumen fluid was collected by an esophageal tube 4 h after the morning feeding on d 28 and 56 to determine ruminal pH, ammonia-N, and volatile fatty acids concentrations. On d 56, 15 (5 per treatment) calves were harvested and slaughter weight, gastrointestinal morphology parameters, and bacteria community were recorded. Papilla length, width, and surface area were measured from 5 locations within the rumen. Villus height, width, surface area, crypt depth, and villus height-to-crypt depth ratio were measured in the duodenum, jejunum, and ileum. Next-generation sequencing technology was used to test the microbial community of the rumen and duodenum samples on d 28 and 56. Data were analyzed by MIXED procedure in SAS (SAS Institute Inc., Cary, NC) with contrast statements to declare CON versus all SCFP and 0.5 versus 1% SCFP in starter grains. Ruminal pH, ammonia-N, and total volatile fatty acids were not altered by SCFP. However, the supplemented groups exhibited higher ruminal butyrate concentrations coinciding with higher Butyrivibrio and lower Prevotella richness than CON group. Supplementation of SCFP increased papilla length in the rumen. In the small intestine, SCFP reduced crypt depth of jejunum, and increased villus height-to-crypt depth ratio in all segments of the small intestine, especially when supplemented at a higher dosage in the starter. In conclusion, Saccharomyces cerevisiae fermentation products improved gastrointestinal morphology, possibly due to increased Butyrivibrio and decreased Prevotella richness of the rumen fluid, which resulted in an increase in butyrate production, and the effect was slightly greater with the higher dosage of SCFP in the starter.

Iron nanoparticle reinforced polyacrylonitrile (PAN) nanocomposites are fabricated by a facile and environmentally benign solvent extraction method. Fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) results indicate a strong interaction between the iron nanoparticles and the polymer matrix for the as-prepared polymer nanocomposites. The heat treatment induces the carbonization of the polymer matrix. High-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analysis show a protecting carbon shell surrounding the iron nanoparticles within the carbon matrix against the particle oxidation. The magnetic properties, electrical conductivity, and magnetic field dependent resistivity of heat-treated nanocomposites with different particle loadings are carried out in a physical properties measurement system by Quantum Design and by a standard four probe method. The saturation magnetization increases and the coercivity decreases with an increase of the nanoparticle loading. The heat-treated nanocomposites possess a room temperature magnetoresistance (MR) of 5.1% at a field of 90 kOe. The nanoparticle loading has a significant effect on the resistivity of nanocomposites. The heat-treated nanocomposites show a particle loading dependent transport mechanism. A transition from semiconductive to metallic conduction was observed with an increase of the nanoparticle loading.