Feeding value of supplemental Jatropha curcas crude oil in finishing diets for feedlot lambs

: The objective of this experiment was to determine the feeding value of a mechanically extracted nontoxic variety of oil (JCO) as source of energy for feedlot lambs. Twenty Pelibuey × Katahdin lambs were individually fed a dry-rolled-corn-based finishing diet supplemented with 0%, 2%, 4%, or 6% JCO (diet dry matter basis). Supplemental JCO replaced dry rolled corn in the basal diet. Fatty acid composition of JCO was C16:0, 14.0%; C18:0, 8.2%; C18:1, 26.0%; C18:2, 50.3%, and C18:3, 0.4%. Daily intakes of JCO averaged 24.7, 51.1, and 77.3 g/day or 0.57, 1.08, and 1.62 g/kg LW for the 2%, 4%, and 6% levels of supplementation, respectively. Supplemental JCO did not affect ( = 0.33) dry matter intake (DMI), but tended to increase (linear effect, = 0.06) average daily gain, efficiency of gain (linear effect, < 0.01), and dietary net energy (linear effect, < 0.01) and decreased (linear effect, < 0.01) the ratio of observed/expected DMI. At low levels (20 g/kg diet dry matter) of supplementation, the net energy (NE) value of JCO corresponds closely (0.99) to the NE value assigned by current standards (), and this NE value decreased linearly as the inclusion level of JCO increased. There were not treatment effects on plasma metabolites. Across treatments, the concentrations of hemoglobin (11.64 ± 1.08 g/dL), hematocrit (39.15 ± 3.67%), glucose (85.2 ± 17.64 mg/dL), creatinine (1.43 ± 0.28 mg/dL), and urea (20.70 ± 4.35 mg/dL) were within normal (9-15 g/dL, 27%-40%, 50-90 mg/dL, 1.0-1.8 mg/dL, and 15-50 mg/dL, for hemoglobin, hematocrit, glucose, creatinine, and urea, respectively) ranges for healthy lambs. Based on DMI, performance and plasma metabolites observed in this study, nontoxic JCO is a suitable source of energy in finishing diets for lambs.