Salinomycin Sodium

Addition of the ionophoric antibiotics salinomycin or narasin to preparations of large unilamellar vesicles made from egg yolk phosphatidylcholine in sodium or potassium chloride solutions gives rise to dynamic effects in the 23Na- and 39K-NMR spectra. The dynamic spectra arise from the ionophore-mediated transport of the metal ions through the membrane. The kinetics of the transport are followed as a function of the concentrations of ionophore and the metal ion and are compatible in all cases with a model in which one ionophore molecule transports one metal ion. For both ionophores the transport of potassium ions is appreciably faster than that of sodium and in both cases the rate-limiting step for sodium transport is dissociation of the ionophore-metal complex. Assuming dissociation to be rate limiting in all four cases it is shown that the transport rate differences between the pairs of complexes of each metal arise solely from differences in the rates of formation.

The distal rabbit colon was used as a model to investigate the influence of the cationophore Salinomycin in vivo with a single-pass perfusion, and in vitro with a modified Ussing chamber technique. For in vivo experiments with labelled 14C-PEG as a volume marker in the perfusate, a dose of 10E-4 mol/l Salinomycin was used. Net water (53 microliters/h/cm), net chloride (3 mumol/h/cm) and net sodium (3.6 mumol/h/cm) absorption was not significantly influenced, but net potassium secretion (-3 mumol/h/cm) was decreased to zero and transepithelial potential (PD) reduced from -45 mV to -33 mV. 10E-4 mol/l Salinomycin, applied in vitro on the muscosal side, decreased PD in 80 min and 10E-3 mol/l in 30 min from 18 mV to zero. Both concentrations decreased the short-circuit current (Isc = 77 microA/cm2) in 60 min, respectively 30 min to 40 microA/cm2. After 60 min mucosal 10E-4 mol/l Salinomycin the Isc increased, resulting from a transepithelial conductance (Gt) increase from 3 to 40 mS/cm2.

Two experiments were conducted to determine the effects of 2 ionic and antimicrobial mixtures on broiler performance and nutrient retention. In experiment 1, male broilers were fed 6 diets in a 2 x 3 factorial experiment (5 cages/diet, 9 chicks/cage) from 0 to 21d of age. Diets with 2 nutrient densities [normal industry diet (ND) and a low nutrient density diet (82% of ND)] and 3 ionic and antimicrobial mixtures [none (control) or 1 of 2 formulations containing different mixtures of ionic salts and oxyhalogenic compounds (sodium salts of chlorite, chlorate, chloride, borate, sulfate, bromide, salicylate, and hydrogen peroxide) at 4.4 mL/kg of feed (mix A and B)]. Birds fed mix B (568.6 g) were heavier (P < 0.05) at 21d of age than birds fed the control diet (501.7 g) and BW of birds fed mix A (536.1 g) did not differ from mix B or controls. Phosphorus and nitrogen retention from 18 to 20 d in birds fed mix B (78.05% and 82.23%, respectively) was greater (P < 0.

An ionophore antibiotic salinomycin was studied in a membrane environment consisting of isotropic bicelles, a better model for biological membranes than micelles, and its conformation and topological orientation in bicelles was determined. 2D NMR measurements and restrained conformational search revealed that salinomycin-sodium salt in bicelles adopts an open conformation in which the orientation of the E-ring is significantly different from that in crystal and solution structures. This conformational alteration breaks an intramolecular hydrogen bond between 28-OH and 1-O, dislocates the ether oxygen of the E-ring from a coordinated position to the sodium ion observed in the crystal, and consequently weakens the complexation between salinomycin and the sodium ion. Paramagnetic relaxation experiments using doxyl-phospholipids reveal that salinomycin is embedded shallowly in bicelles, with both terminals being closer to the water interface and the olefin portion facing the bicelle interior.