Nutritive Value Assessment of Four Crop Residues by Proximate Composition and In Vitro Rumen Fermentation Techniques
This study estimated the proximate composition and in vitro gas production parameters of rice husk, bean waste, citrus pulp and maize stover, in a rumen incubation system. The incubation was for 24 h with measurement of gas production volume over incubation periods of 3, 6, 9, 12, 15, 18, 21 and 24 hours. The crude protein ranged 1.92 to 11.75% and the crude fibre ranged between 9.68 and 45.09%. The potential gas production (a+b) was rated highest in both citrus pulp and maize stover (48.33 ml), next was bean waste (42.00 ml) and lowest was rice husk (25 ml). The ranges of values of metabolizable energy (ME), organic matter digestibility (OMD) and short chain fatty acids(SCFA) were 6.33 to 9.24 MJ/kg DM, 52.70 to 64.69 % and 0.94 to 1.09 μmol respectively. The values of ME, OMD and SCFA ranked as, citrus pulp > maize stover> bean waste > rice husk. The higher values obtained for the potential gas production (a+b), ME, OMD and SCFA in citrus pulp and maize stover could imply higher nutrient availability for the rumen micro-organisms. The results revealed that citrus pulp and maize stover could be of higher nutritional value in ruminants feed than bean waste, while rice husk was lowest.