Designing and evaluation of sodium selenite nanoparticles in vitro to improve selenium absorption in ruminants

Sodium selenite is used to prevent selenium deficiency known as nutritional muscular dystrophy or white muscle disease. In ruminants, selenium supplements are transformed partiality in insoluble form by ruminal microorganisms and its process decrease the selenium absorption in digestive gastrointestinal. However, the objective in this research was focused in encapsulated sodium selenite to be release into of a pH less than four, similarity to an intestinal environment. It was encapsulated by nanoprecipitation and emulsion–evaporation methods, within polymeric nanoparticles. The effect of these methods, polymer proportion (Eudragit RL and RS) and solvent (ethanol and acetone) on the physicochemical (drug entrapment, polidispersity index (PDI) and z potential) and morphological characteristics (particle morphology and particle size) were evaluated. Particle size from each nanoparticles, formulation ranged from 36.64 to 213.86 nm. Particle size, z potential and PDI increased (P ≤ 0.01) when nanoprecipitation and ethanol were used. No significant differences (P > 0.05) were observed when different polymeric proportions were used. Selenium entrapment was 26% when emulsion–evaporation method was used and 78% with nanoprecipitation. Nanoparticles produced by nanoprecipitation were spherical and had a great variation in particle size; on the other hand, nanoparticles produced by emulsion–evaporation were spherical as well as amorphous and presented a homogeneous nanopartcicle size distribution. The release of selenium from nanoparticles was higher in acid pH (less than 4), this condition may represent a better availability of the mineral in the small intestine

Diseño y evaluación de nanoparticulas de selenito de sodio para su uso en rumiantes

El selenito de sodio, el suplemento de selenio mas usado en rumiantes en la prevención de la deficiencia del elemento y las enfermedades resultantes, fue encapsulado por nanoprecipitación y emulsión-evaporación en nanopartículas poliméricas. Fue evaluado el efecto del método de preparación de nanoparticulas, proporciones de polímeros (Eudragit RL 100 y RS 100) y solvente empleado (etanol y acetona), sobre las características fisicoquímicas (potencial z, índice de polidispersidad y porcentaje de encapsulación) y la morfología (tamaño de partícula y forma) de las nanopartículas. El tamaño de partícula obtenido presentó valores de 34.64 a 213.86 nm. Tanto el tamaño como el potencial z y el PDI se incrementaron (P < 0.05) cuando se utilizó el método de nanoprecipitación al igual que cuando se utilizó el solvente etanol. No se encontraron diferencias significativas (P > 0.05) para las diferentes proporciones de polímeros, probablemente porque las diferencias entre las proporciones no eran tan marcadas. Con el método de emulsión-evaporación se obtuvo un porcentaje de encapsulación de 26% mientras que con el método de nanoprecipitación la encapsulación fue de 78%. Las nanopartículas que se formaron con el método de nanoprecipitación presentaron una forma esférica con una gran variación en el tamaño, mientras que las observadas en el método emulsión-evaporación fueron tanto esféricas como irregulares con un tamaño de partícula más homogéneo. La liberación de selenio de las nanopartículas fue mayor en condiciones de pH acido. Esta condición puede representar una mejor disponibilidad del selenio a nivel intestinal. _________Sodium selenite, predominant selenium supplement for ruminants used in the prevention of selenium deficiency and the treatment of nutritional muscular dystrophy (white muscle disease) and cardiac myopathy, was encapsulated by nanoprecipitation and emulsion-evaporation methods, within polymeric nanoparticles. The effect of methods, polymer proportion (Eudragit RL and RS) and solvent (ethanol and acetone) on the physicochemical (drug entrapment, polidispersity index (PDI) and z potential) and morphological characteristics (particle morphology and particle size) was evaluated. Particle size from each nanoparticle formulation ranged from 36.64 to 213.86 nm. Particle size, z potential and PDI increased when nanoprecipitation and ethanol were used. No significant differences were observed when different polymeric proportions were used. Selenium entrapment was 26% when emulsion-evaporation method was used and 78% with nanoprecipitation. Nanoparticles produced by nanoprecipitation were spherical and present a great variation in particle size, on the other hand, nanoparticles produced by emulsion-evaporation were spherical as well as amorphous and present a homogeneous nanopartcicle size distribution. The release of selenium from nanoparticles was higher in acid pH, this condition may represent a better availability of the mineral in the small intestine.Tesis (Maestría en Ciencias, especialista en Ganadería).- Colegio de Postgraduados, 2008.CONACY

Estimating gas volume from headspace pressure in a batch culture system

Two in vitro batch culture experiments were conducted to obtain a total of 1811 paired data for headspace gas pressure (GP; PSI) and volume (GV; mL). Data were used to generate and evaluate an equation to estimate GV from GP under our lab conditions (GV = 4.7047GP + 0.0512 GP2).The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Rumen fermentation of feed samples incubated in filter bags made from different textiles or dispersed in the medium using an in vitro gas production system

ABSTRACT: The effect of different feed substrates incubated in filter bags [no bag (NB); Ankom® F57, 25 μm pore size (25AN); polyester, 45 μm pore size (45PB); polyester, 67 μm pore size (67PB) ] or dispersed in the medium on gas production, digestion and rumen fermentation was evaluated using an in vitro gas production system. Filter bags reduced (P < 0.01) gas production but increased (P < 0.01) the in vitro dry matter digestibility (45PB and 67PB). Additionally, the use of filter bags with smaller pore size, reduced total volatile fatty acid (P < 0.01), but had minimal effects on acetate, propionate, and butyrate concentration. Our research suggested that using filter bags with a pore size of 67 µ would reduce some negative effects of incubating feed substrate dispersed in the medium or in filter bags with smaller pore size. However, the use of bags with a larger pore size might allow the wash out of small feed particles with consequent overestimation of digestibility

Effect of Encapsulated Nitrate and Microencapsulated Blend of Essential Oils on Growth Performance and Methane Emissions from Beef Steers Fed Backgrounding Diets

A long-term study (112 days) was conducted to examine the effect of feeding encapsulated nitrate (NO3&minus;), microencapsulated blend of essential oils (EO), and their combination on growth performance, feeding behavior, and enteric methane (CH4) emissions of beef cattle. A total of 88 crossbred steers were purchased and assigned to one of four treatments: (i) control, backgrounding high-forage diet supplemented with urea (1.17% in dietary DM); (ii) encapsulated NO3&minus; (EN), control diet supplemented with 2.5% encapsulated NO3&minus; as a replacement for urea (1.785% NO3&minus; in the dietary DM); (iii) microencapsulated blend of EO (MBEO), control diet supplemented with 150 mg/kg DM of microencapsulated blend of EO and pepper extract; and (iv) EN + MBEO, control diet supplemented with EN and MBEO. There was no interaction (p &ge; 0.080) between EN and MBEO on average dry matter intake (DMI), average daily gain (ADG), gain to feed ratio (G:F), feeding behavior, and CH4 emission (using GreenFeed system), implying independent effects of feeding EN and MBEO. Feeding MBEO increased CH4 production (165.0 versus 183.2 g/day; p = 0.005) and yield (18.9 versus 21.4 g/kg DMI; p = 0.0002) but had no effect (p &ge; 0.479) on average DMI, ADG, G:F, and feeding behavior. However, feeding EN had no effect on ADG and G:F (p &ge; 0.119) but reduced DMI (8.9 versus 8.4 kg/day; p = 0.003) and CH4 yield (21.5 versus 18.7 g/kg DMI; p &lt; 0.001). Feeding EN slowed (p = 0.001) the feeding rate (g of DM/min) and increased (p = 0.002) meal frequency (events/day). Our results demonstrate that supplementing diets with a blend of EO did not lower CH4 emissions and there were no advantages of feeding MBEO with EN. Inclusion of EN as a replacement for urea reduced CH4 emissions but had no positive impact on animal performance