Rumen Degradation of Cassava Peel Meal Supplemented with Graded Levels of African Yambean by West African Dwarf Sheep in the Humid Zone of Nigeria

The effect of 0,10, 20 and 30% supplementation of cassava peel (Manihot esculenta Crantz) with African yambean (Sphenostylis stenocarpa-AYB) on rumen degradability of dry and organic matter (DM and OM) was investigated in a factorial experiment involving 4 treatments, 5 incubation periods, 3 animals and 2 nylon-bag samples per animal per incubation period. Three rumen-fistulated West African Dwarf ewes of 30 months of age and weighing an average of 31kg were used. Samples were incubated in the rumen for 6, 12, 24, 48 and 72 hours. DM and OM degradation increased significantly (P< 0.05) when the legume (AYB) fraction in the diets increased from 0 to 20%. Any further increase in the legume fraction up to 30% of the diet did not result in significant increases in DM and OM degradability. Also a significant (P< 0.05) increase in DM and OM degradability of all diets was recorded when incubation time in the rumen increased from 6 to 48 hours. Degradability of DM was 31% for cassava peel alone and 32, 38 and 39% respectively, for rations containing 10, 20 and 30% legume inclusion after 48 hours incubation. There was no significant (P> 0.05) increase in DM and OM degradability after 72 hours incubation time. The estimates of the immediate soluble fraction (a) and the rate of degradability (c) increased with increase in the level of AYB inclusion in the diets. As the level of AYB supplement increased, the lag time necessary for the microbial population to invade the feed also reduced appropriately. The study concludes that the inclusion of African yambean supplement in the diet of WAD sheep fed cassava peel meal up to 20% resulted in significant improvement in dry matter and organic matter degradation in the rumen.