In this study, four experimental treatments were evaluated: (T1) alfalfa hay + concentrate, (50:50%, DM); (T2) alfalfa hay + Leucaena leucocephala + concentrate, (30:20:50%, DM); (T3) alfalfa hay + prickly pear + concentrate, (30:20:50%, DM); and (T4) alfalfa hay + Leucaena leucocephala + prickly pear + concentrate, (30:10:10:50%, DM). NH3-N concentrations in T2 and T4 decreased when replaced with alfalfa hay in 20 and 10%, respectively. Treatments did not affect the concentration of total volatile fatty acids (TVFA) between T3 and T4 (p > 0.05), while the concentrations among T1 and T2 were different (p < 0.05). T2 showed a reduction of 25.5% in the methane production when compared to T1 (p < 0.05). The lowest concentrations of protozoa were observed in T2 and T4, which contained Leucaena leucocephala (T2) and Leucaena leucocephala + prickly pear (T4) (p < 0.05). The highest concentration of total methanogens was recorded in T1 and was different in T2, T3, and T4 (p < 0.05). Leucaena leucocephala, at an inclusion percentage of 20%, decreased the methane when compared to T1, whereas prickly pear increased methane production in relation to T1.

USO DE UN REACTOR DE PLACA PLANA (TiO2/VIDRIO) PARA LA DEGRADACIÓN DE 2,5-DICLOROFENOL POR FOTOCATÁLISIS SOLAR

In this study, four experimental treatments were evaluated: (T1) alfalfa hay + concentrate, (50:50%, DM); (T2) alfalfa hay + Leucaena leucocephala + concentrate, (30:20:50%, DM); (T3) alfalfa hay + prickly pear + concentrate, (30:20:50%, DM); and (T4) alfalfa hay + Leucaena leucocephala + prickly pear + concentrate, (30:10:10:50%, DM). NH3-N concentrations in T2 and T4 decreased when replaced alfalfa hay in 20 and 10 %, respectively. Treatments did not affect the concentration of total volatile fatty acids (TVFA) between T3 and T4 (p>0.05); while the concentrations among T1 and T2 were different (P<0.05). T2 showed a reduction of 25.5 % in the methane production when compared to T1(p < 0.05).The lowest concentrations of protozoa were observed in T2 and T4, which contained Leucaena leucocephala (T2) and Leucaena leucocephala + prickly pear (T4) (p<0.05). The highest concentration of total methanogens was recorded in T1 and were different to T2, T3 and T4 (p<0.05). Leucaena leucocephala at a inclusion percentage of 20 % decreased the methane when compared to T1; whereas prickly pear there was not a positive effect the methane production.

Durango State has the denomination of origin for the production of mezcal, which is made from Agave durangensis, mainly in an artisanal way; therefore, differences in the fermentation process affect the quality of the final product. The main objective of the present study was to evaluate the diversity of culturable yeasts involved in the artisanal and semi-technified process of mezcal production in the State of Durango. Three distilleries with different production processes were monitored at different fermentation stages (beginning, mid-fermentation, and end of fermentation) in the spring and summer seasons. A greater diversity was found in the distillery of Nombre de Dios in both the spring and summer production seasons (H’ = 1.464 and 1.332, respectively), since it maintains an artisanal production process. In contrast, the distillery of Durango, where a Saccharomyces cerevisiae commercial inoculum is used to start fermentation, presented low diversity indexes (H’ = 0.7903 and 0.6442) and only S. cerevisiae, Kluyveromyces marxianus, and, sporadically, Pichia manshurica were found. Results suggest that the yeast microbiota involved in mezcal fermentation during the different seasons is affected by the type of inoculum; changes include the presence of some species that were only identified during a specific season in alcoholic fermentation, such as Torulaspora delbrueckii and Pichia kluyveri.

Objetivo. Evaluar las propiedades fisicoquímicas, digestibilidad In vitro y digestibilidad aparente de nitrógeno en materia fecal y orina de cerdos de un alimento extrudido usando frijol (Phaseolus vulgaris L.) como sustituto de harina de soya. Materiales y métodos. Se estandarizó el proceso de extrusión para dos formulaciones de harina de frijol (Pinto Saltillo), harina de maíz (Cafime) y harina de soya a diferentes proporciones: 20/67/13% y 30/60/10%, respectivamente. Las muestras se procesaron en un extrusor monotornillo a 120-150°C y 18-22% de contenido de humedad. Las propiedades fisicoquímicas evaluadas fueron: índice de expansión, densidad aparente, índice de absorción de agua, índice de solubilidad en agua, dureza, actividad de agua y parámetros de color: L*, a* y b*. La digestibilidad In vitro y digestibilidad aparente de nitrógeno en materia fecal y orina de cerdos se evaluaron usando el tratamiento óptimo previamente obtenido buscando disminuir costos de procesamiento. Resultados. Las condiciones óptimas para la formulación de 20% de harina de frijol fueron 124.4°C y 18.59% de contenido de humedad. La temperatura de extrusión redujo la densidad aparente, dureza y actividad de agua, pero incrementó L* y el índice de expansión. El contenido de humedad redujo la densidad aparente, actividad de agua, dureza y a*. La digestibilidad In vitro de materia seca fue mayor para la dieta de frijol extrudido en comparación a la dieta control (92.33% vs. 85.33%). Conclusiones. Los resultados indican que la harina de frijol es una opción viable para el consumo animal en términos de valor nutricional y digestibilidad.