Evaluation of Rumen Degradable Protein Values from Various Tropical Foliages Using in Vitro and in Situ Methods
Unknown authors
Abstract
There are no recommended methods for obtaining rumen degradable protein (RDP) values of tropical foliage to meet ruminant feed quality standards.Different methods have produced different RDP values, prompting this study to compare and adjust values of RDP in tropical foliage obtained using both in situ and in vitro methods.Nine types of tropical foliages (Gliricidia sepium, Leucaena leucocephala, Calliandra calothyrsus, Indigofera zollingeriana, Moringa oleifera, Calopogonium mucunoides, Arachis hypogaea, Sesbania grandiflora, and Arachis pintoi) were analyzed for their chemical composition (ash, crude protein (CP), crude fiber (CF), ether extract (EE), neutral detergent fiber (NDF) and acid detergent fiber (ADF) using proximate analysis, Van Soest's fiber fraction, and Cornell protein fraction.The samples were then evaluated for their degradation characteristics, including dry matter degradation (DMD), organic matter degradation ( OMD), and RDP in rumen using 1) conventional or first-stage in vitro rumen fermentation technique, 2) modification of the first-stage in vitro method, and 3) in situ method.The evaluation was performed in three consecutive runs using a completely randomized design for chemical analysis and a randomized complete block design for degradation study.The result shows that I. zollingeriana, M. oleifera, L. leucocephala, and G. sepium are among the best tropical foliage for ruminants due to their higher CP, DMD, OMD, and RDP values resulting from lower CF, NDF and ADF values.C. calothyrsus, with its high CP and low fiber, resulted in DMD, OMD and RDP values but its high tannin content in the foliage may be a limiting factor.Conventional and in situ produced similar degradation characteristics, significantly higher than in vitro modification.It is recommended to cultivate I. zollingeriana, M. oleifera, L. leucocephala, and G. sepium for ruminant protein supplements, and it is suggested to use standard in vitro to obtain a precise RDP value of tropical foliages.