Dietary supplementation with sodium gluconate improves the growth performance and intestinal function in weaned pigs challenged with a recombinant Escherichia coli strain.

BACKGROUND: The purpose of this research is to determine the effects of sodium gluconate (SG) on the growth performance and intestinal function in weaned pigs challenged with a recombinant Escherichia coli strain expressing heat-stable type I toxin (STa). RESULTS: Pigs (n = 24, 21 days of age) were randomly allocated to three treatments: Control group (pigs were fed basal diet), STa group (pigs were fed basal diet and challenged with a recombinant E. coli strain expressing STa), and SG group (pigs were fed basal diet supplemented with 2500 mg/kg sodium gluconate and challenged with a recombinant E. coli strain expressing STa). The trial period lasted for 15 days. On days 12 and 13, pigs in the STa and SG groups were orally administered with the recombinant Escherichia coli strain, while those in the control group were orally administered with normal saline at the same volume. On day 15, blood, intestinal tissues and colonic contents were collected for further analysis. Results showed that dietary SG supplementation had a tendency to increase average daily gain, and reduced (P < 0.05) feed to gain ratio, plasma glucose concentration, and mean corpuscular hemoglobin concentration as compared with control group on days 0-10 of trial. Additionally, dietary SG supplementation attenuated(P < 0.05) the morphological abnormalities of small intestinal and the increase of the number of eosinophils in blood of pigs challenged with the recombinant Escherichia coli strain on day 15 of trial. Compared with control group, diarrhea rate and the number of eosinophils in blood and the concentrations of malondialdehyde in the jejunum were increased (P < 0.05). The height, width and surface area of the villi of the duodenum, the width and surface area of villi of jejunum and the height and width of villi of ileum were decreased (P < 0.05) in pigs challenged with the recombinant Escherichia coli strain in the STa group compared with those in control group on day 15 of trial. However, these adverse effects were ameliorated (P < 0.05) by SG supplementation in the SG group on day 15 of trial. Furthermore, dietary SG supplementation could reduce (P < 0.05) the total bacterial abundance in the colon, but SG did not restore the recombinant Escherichia coli-induced microbiota imbalance in colon. CONCLUSIONS: In conclusion, dietary supplementation with SG could improve piglet growth performance and alleviate the recombinant Escherichia coli-induced intestinal injury, suggesting that SG may be a promising feed additive for swine.

Hydrodynamics of immiscible binary fluids with viscosity contrast: a multiparticle collision dynamics approach.

We present a multiparticle collision dynamics (MPC) implementation of layered immiscible fluids A and B of different shear viscosities separated by planar interfaces. The simulated flow profile for imposed steady shear motion and the time-dependent shear stress functions are in excellent agreement with our continuum hydrodynamics results for the composite fluid. The wave-vector dependent transverse velocity auto-correlation functions (TVAF) in the bulk-fluid regions of the layers decay exponentially, and agree with those of single-phase isotropic MPC fluids. In addition, we determine the hydrodynamic mobilities of an embedded colloidal sphere moving steadily parallel or transverse to a fluid-fluid interface, as functions of the distance from the interface. The obtained mobilities are in good agreement with hydrodynamic force multipoles calculations, for a no-slip sphere moving under creeping flow conditions near a clean, ideally flat interface. The proposed MPC fluid-layer model can be straightforwardly implemented, and it is computationally very efficient. Yet, owing to the spatial discretization inherent to the MPC method, the model can not reproduce all hydrodynamic features of an ideally flat interface between immiscible fluids.

Protective Effect of Zinc Oxide and Its Association with Neutrophil Degranulation in Piglets Infected with Porcine Epidemic Diarrhea Virus.

Porcine epidemic diarrhea virus (PEDV) has reemerged throughout the world in the past ten years and caused huge economic losses to the swine industry. No drugs are available to prevent or treat PEDV infection in piglets. Zinc oxide (ZnO) has been shown to reduce diarrhea. However, little is known about its role in PEDV infection. In this study, twenty-four 7-day-old piglets were randomly divided into three treatment groups: control, PEDV, and ZnO+PEDV. Piglets in the ZnO+PEDV group were orally administered with 100 mg/kg·BW ZnO and then inoculated PEDV at a dose of 104.5 TCID50 (50% tissue culture infectious dose) per pig. Growth performance, histologic lesions, viral load, indicators of intestinal damage, inflammation, and oxidative stress were recorded or detected to determine the effect of ZnO on PEDV infection. And the underlying mechanisms were revealed by microarray and proteomic analyses. Results showed that ZnO administration mitigated diarrhea and the reduction of average daily weight gain induced by PEDV infection. ZnO could inhibit PEDV replication in the small intestine and colon. Both villus height and crypt depth were affected by PEDV infection in the duodenum and jejunum, which could be rescued by ZnO administration. Moreover, the activity of catalase was decreased both in plasma and intestine after PEDV infection, while increased in the intestine by ZnO administration. PEDV infection also significantly increased the concentration of H2O2 in jejunal and ileum and decreased the activity of total superoxide dismutase and glutathione peroxidase in plasma, whereas ZnO administration obviously increased the activity of total superoxide dismutase and decreased the concentration of H2O2 in the ileum. The concentrations of IL-1ß, IL-6, and IL-8 in the plasma were all decreased upon ZnO administration. A large number of differentially expressed genes and proteins were identified in the ileum among the three groups by microarray and proteomic analyses. Gene Ontology and Reactome pathway analyses indicated that neutrophil degranulation and nutrient metabolism were the main biological process and pathways in both PEDV infection and ZnO administration. Overall, ZnO administration could improve growth performance, intestinal redox status, morphology, and function and reduce diarrhea in PEDV-infected piglets; ZnO could exert antiviral and anti-inflammatory effects on PEDV-infected piglets probably through regulating neutrophil degranulation. Our findings have important implications in piglet and infant nutrition.

Anisotropic thermophoresis.

Colloidal migration in a temperature gradient is referred to as thermophoresis. In contrast to particles with a spherical shape, we show that elongated colloids may have a thermophoretic response that varies with the colloid orientation. Remarkably, this can translate into a non-vanishing thermophoretic force in the direction perpendicular to the temperature gradient. Opposite to the friction force, the thermophoretic force of a rod oriented with the temperature gradient can be larger or smaller than when oriented perpendicular to it. The precise anisotropic thermophoretic behavior clearly depends on the colloidal rod aspect ratio, and also on its surface details, which provides an interesting tunability to the devices constructed based on this principle. By means of mesoscale hydrodynamic simulations, we characterize this effect for different types of rod-like colloids.