In vitro gas production of leaves and pods of fodder trees from dry tropic using bovine faeces as inoculums

The kinetics of in vitro gas production to achnowledge the nutritional potential of tree leaves and pods that grow in a dry tropical area of Mexico using bovine faeces as inoculum, compared with guinea grass ( Panicum maximum ) as reference was studied. Leaves and pods were collected from: Prosopis laevigata , Pithecellobium dulce and Pithecellobium acatlense ; and only leaves from: Amelanchier denticulata , Verbesiana crocata , Haemotoxylum brasiletto , Acacia bilimekii , Acacia pennatula , Acacia constricta and Lantana velutina . The inoculums were prepared with fresh bovine faeces dissolved in water in 1:3 ratio. Parameters estimated were the maximum gas production (v), the production rate (s) and the lag phase (l). Three species showed low gas values (8,34-11,4 ml) while most were close to those of guinea grass (29 ml) with a similar production rate (0,03 h-1). In the pods, with exception of Pithecellobium acatlense, the others presented a higher gas production (33,8-46,3 ml) than guinea grass (25,6 ml) with a rate of production similar o greater (0,03 a 0,06 h-1). The results indicate that the pods of Prosopis laevigata and Pithecellobium dulce have nutritional value superior to that of guinea grass while leaves from Haemotoxylum brasiletto and Prosopis laevigata have a similar value. The gas production technique in vitro allows the estimation of the potential value of non-conventional feed resources. Se estudió la cinética de producción de gas in vitro para conocer el potencial nutricional de hojas de arbóreas y vainas que crecen en una zona tropical seca de México usando heces bovinas como inóculo, comparadas con el pasto guinea como referencia ( Panicum maximum ). Se colectaron hojas y vainas de: Prosopis laevigata , Pithecellobium dulce y Pithecellobium acatlense ; y sólo hojas de: Amelanchier denticulata , Verbesiana crocata , Haemotoxylum brasiletto , Acacia bilimekii , Acacia pennatula , Acacia constricta y Lantana velutina . El inóculo se preparó con heces bovinas recién depuestas disueltas en agua en proporción 1:3. Se estimaron los parámetros de la velocidad máxima de producción de gas (v), la tasa de producción (s) y la fase lag (l). Tres especies mostraron bajos valores de gas (8,34-11,4 ml), mientras que la mayoría fueron cercanos a los del pasto guinea (29 ml) con una tasa de producción similar (0,03 h-1). Con excepción de la vaina de Pithecellobium acatlense, el resto tuvo mayor producción de gas (33,8-46,3 ml) que el pasto guinea (25,6