Nutrient digestibility and metabolizable energy content of Mucuna pruriens beans fed to growing Pelibuey lambs

The nutrient digestibility, nitrogen balance and in vivo metabolizable energy supply of Mucuna pruriens beans fed to growing Pelibuey lambs were investigated. Eight Pelibuey sheep housed in metabolic crates were fed increasing levels of raw M. pruriens beans. Treatments according to Mucuna inclusion level (g/kg dry matter) were: 0 (control), 100 (Mucuna100), 200 (Mucuna200) and 300 (Mucuna300) g/kg dry matter. The control diet consisted of sorghum grain, soybean meal, Cynodon nlemfluensis grass hay and calcium carbonate. Dry matter (DM), N and gross energy (GE) intakes were similar (P>0.05) across treatments. Increasing M. pruriens beans in the diet resulted in a linear increase (P<0.005) in DM, N and GE apparent digestibility from 0.64, 0.57 and 0.64 to 0.73, 0.69 and 0.72 from 0 to 300 g Mucuna/kg DM respectively. There was no effect of inclusion level of M. pruriens bean on N retention (P>0.05), but GE retention coefficient increased (P<0.01) from 0.55 to 0.63 from diets of 0 to 300 g Mucuna/kg DM respectively. Nitrogen balance was positive and similar across all treatments (P>0.05). The DM, N and GE apparent digestibility coefficients of M. pruriens beans obtained using multiple regression equations were 0.89, 0.82 and 0.87 respectively. In vivo digestible (DE) and metabolizable energy (ME) content of Mucuna bean were estimated as 14.1 and 12.6 MJ/kg DM respectively. It was concluded that raw M. pruriens beans ME value compares favorably with ME values of conventional feed resources. This is the first in vivo estimation of the ME value of Mucuna bean for ruminants.