Evaluation of nutrient content and in Vitro gas fermentation of some crop residues as feed supplements for ruminants

Abstract

The objective of this study was to evaluate the nutritive value of Yam peel (YP), Maize chaff (MC) and Rice straw (RS). Evaluation of the nutrient and anti-nutrient content of the crop residues involved determination of the proximate, mineral and phytochemical contents of YP, MC and RS. In vitro gas production (IVGP) of crop residues was carried out over a period of 24 hr incubation to predict Metabolizable energy (ME), organic matter digestibility (OMD) and short chain fatty acids (SCFA). Methane (CH4) was measured by introducing 10 M NaOH into the inoculums after incubation. Result revealed significant (p<0.05) differences in the values of the proximate composition. The dry matter ranged between 85.55 and 92.18 g/100 g in YP and MC respectively. The highest crude protein (5.01 g/100 g) was obtained in MC, while the lowest (4.00 g/100 g) was recorded for YP. The crude fibre ranged between 25.05 g/100g and 41.49 g/100g (YP). The mineral content of YP, MC and RS were not significantly different from each other, but within acceptable limit for optimum metabolism. YP, MC and RS were implicated for anti-nutrients, though no significant. The IVGP varied significantly (p< 0.05) with the MC recording the highest (30.10ml) value, while the lowest (23.96ml) value was obtained in YP. Same trend was observed for ME, OMD, SCFA and CH4 ranging from 5.32– 11.12 MJ/Kg DM; 35.13 – 64.14 %; 0.50- 1.12 μmol and 9.05 – 11.00ml respectively. It can be concluded that YP, MC and RS has potential in livestock nutrition. Also the problem associated with disposal of crop residues can be conveniently reduced by incorporating them into ruminant feed.