Resumen En el trópico mexicano la ganadería está basada en sistemas de producción extensivos y es importante conocer el contenido nutricional de los forrajes, por ello el objetivo del presente estudio fue evaluar la composición química de: Cenchrus ciliaris L., Megathyrsus maximus cv Guinea, Ixophorus unisetus y Megathyrsus maximus cv Tanzania, gramíneas establecidas y utilizadas con frecuencia en el trópico para la alimentación animal. Las muestras provenientes del Rancho ‘San Luis Tenango’, Tonaya, Jalisco se analizaron en el Laboratorio de Nutrición Animal, Departamento de Zootecnia, Universidad Autónoma Chapingo. Se determinó: cenizas (Cen), proteína cruda (PC), extracto etéreo (EE), fibra detergente neutro (FDN), contenido celular (CC), fibra detergente ácido (FDA) y celulosa (Cel). El análisis de los datos se hizo con tres repeticiones y cada repetición se consideró una unidad experimental. Se realizaron la correlación de Pearson y la separación de medias por Tukey (p< 0.05). La PC resultó correlacionada positivamente con Cen y CC y negativamente con FDN y FDA (p< 0.05). Megathyrsus maximus cv Guinea fue la especie forrajera con mayor cantidad de PC (12.9 g (100 g)-1), seguida por (p< 0.05) Megathyrsus maximus cv Tanzania (8.7 g (100 g)-1). Megathyrsus maximus cv Guinea mostró el mayor porcentaje de Cen, 11.7 g (100 g)-1 y los valores más bajos valores de FDA y Cel y su valor de FDN (74.8 g (100 g)-1) fue bajo (p< 0.05), levemente superior al de Ixophorus unisetus (73.5 g (100 g)-1). Por tanto, Megathyrsus maximus cv Guinea fue la gramínea con mayor valor nutricional.

Abstract In the Mexican tropics, livestock farming is based on extensive production systems, and it is important to know the nutritional content of forages, therefore the objective of this study was to evaluate the chemical composition of: Cenchrus ciliaris L., Megathyrsus maximus cv Guinea, Ixophorus unisetus and Megathyrsus maximus cv Tanzania, grasses established and frequently used in the Tropics for animal feed. The samples from the locality ‘San Luis Tenango’, Tonaya, Jalisco were analyzed at the Laboratory of Animal Nutrition, Department of Zootechnics, Chapingo Autonomous University. The following was determined: ashes (Ash), crude protein (CP), ethereal extract (EE), neutral detergent fiber (NDF), cellular content (CC), acid detergent fiber (ADF) and cellulose (Cel). Data analysis was performed with three repetitions and each repetition was considered an experimental unit. Pearson’s correlation and the separation of means by Tukey (p< 0.05) were performed. CP was positively correlated with Ash and CC and negatively correlated with NDF and ADF (p< 0.05). Megathyrsus maximus cv Guinea was the forage species with the highest amount of CP (12.9 g (100 g)-1), followed by (p< 0.05) Megathyrsus maximus cv Tanzania (8.7 g (100 g)-1). Megathyrsus maximus cv Guinea showed the highest percentage of Ash, 11.7 g (100 g)-1 and the lowest values of ADF and Cel and its NDF value (74.8 g (100 g)-1) was low (p< 0.05), slightly higher than that of Ixophorus unisetus (73.5 g (100 g)-1). Therefore, Megathyrsus maximus cv Guinea was the grass with the highest nutritional value.

The objective of the present study was to determine the nutritive value, the presence of antioxidant compounds, and the antioxidant capacity of coffee pulp ensiled or non-ensiled. Dry matter (DM), crude protein (CP), ash, acid detergent fiber (ADF), neutral detergent fiber (NDF), and lignin, as well as the antioxidant compounds present in coffee pulp and their antioxidant capacity, were determined. A completely randomized design was used. Data were analyzed by analysis of variance. Ensiling of coffee pulp increased the CP content from 98.6 to 111.6 g kg−1 DM, NDF from 414.6 to 519.5 g kg−1 DM, ADF from 383.9 to 439.3 g kg−1 DM, and lignin from 122.9 to 133.6 g kg−1 DM. Caffeine decreased from 5.72 to 5.02 mg g−1 DM. Three antioxidant compounds were detected. Caffeic acid decreased due to ensiling (16.49 vs 14.69 mg g−1 DM). Gallic acid (2.88 vs 2.58 mg g−1 DM) and chlorogenic acid (62.12 vs 56.00 mg g−1 DM) did not differ, and there was similar antioxidant capacity of non-ensiled (215.66 µmol trolox g−1 DM) and ensiled coffee pulp (206.59 µmol trolox g−1 DM). Despite the decrease in the caffeic acid content due to the ensiling process, it is possible to use either ensiled or non-ensiled coffee pulp for animal feeding because of its high antioxidant capacity.