NUTRITIVE VALUE, FIBER DIGESTIBILITY AND METHANE PRODUCTION POTENTIAL OF TROPICAL FORAGES IN RABBITS: EFFECT OF SPECIES AND HARVEST MATURITY - K. Khan; S. Khan; S. Ullah; N. A. Khan2; I. Khan; N. Ahmad (Journal of Animal and Plant Sciences, 2017)
The aim of this study was to quantify the nutrient composition, neutral detergent fibre (NDF) digestibility (in vitro) and methane (CH4) emission potential of commonly used tropical forages in rabbits. Seven fodder species, namely, Trifolium alexandrinum, Trifolium resupinatum, Avena sativa, Triticum aestivum, Hordeum vulgare, Brassica campestris, Cichorium intybus; and seven grass species, namely, Pennisetum purpureum, Panicum antidotale, Cenchrus ciliaris, Pennisetum orientale, Setaria anceps and Atriplex lentiformis were evaluated at early, mid and late stages of maturity. At each maturity, samples were collected from four replicate plots of each species, and subsequently analyzed for the contents of dry matter (DM) and nutrient composition. The DM and NDF degradability, and CH4 emission was measured using an in vitro gas production system. The CH4 concentration in the gas was measured using Gas Chromatography. Large variation (P < 0.001) was observed for contents of all measured chemical components among the forage species. With advancing maturity, the contents of crude protein (CP), ether extract, and hemicelluloses decreased (P ˂ 0.001) with concomitant increase (P ˂ 0.001) in NDF content. Moreover, in vitro DM and NDF degradability decreased (P ˂ 0.001) and CH4 emission increased (P ˂ 0.001) with increasing maturity. Overall, the fodder species had higher fiber digestibility and produce less CH4 as compared to grass species, and among the fodder species T. alexandrinum had higher fiber degradability (48%) and produced less CH4 (7.2 ml/ 100 g organic matter) at early maturity, and could be an ideally fed to rabbits as forage sources. This study highlights that forage species and harvest maturity has a profound influence on nutrients supply to rabbit and on CH4 emission to the environment.
Keywords: journal article; Nutrient composition; In vitro digestion; Methane production; Harvest maturity; Tropical forages