Fermentability and Digestibility of Ration Containing Crude Curcin Extract of Jatropha curcas L. Seed Meal

Abstract

Jatropha (J.) curcas L. seed meal (JCSM) is a byproduct of J. curcas L. oil extraction. This JCSM contains high protein concentration (37.56% DM) and ether extract (35.02% DM) which makes a potential source of animal feed. However, JCSM utilization can be limited by the presence of antinutrients such as curcin or lectin, and phorbolester. These antinutrients, especially the curcin, can be digested differently by microbes from the rumen fluid of cattle and buffalo. Therefore, an ex-periment was conducted to study fermentability and digestibility (in vitro) of ration that contain crude curcin extracted from Jatropha curcas L. seed meal by microbes from the rumen fluid of cattle and buffalo. Factorial randomised block designs were used in fermentability (4x2x2), and digestibility (4x2) studies; three replications were used in both experiments. The treatments were levels of crude curcin extracted from JCSM (0, 1, 2 and 3% v/w) that were added into rations as factor A, microbes from the rumen fluid of cattle and buffalo as factor B, and incubation times (0 and 3 h) as factor C in fermentability study; factors A and B were also applied as treat-ments in digestibility experiment. Variables measured were ammonia and total VFA concentrations, total bacterial and protozoal populations, and dry matter (DM) and organic matter (OM) digestibilities. Data were analysed using analysis of variance, and differences in treatment means were examined with contrast or polynomial or-thogonal. The results showed that effects of addition levels of crude curcin extracts into rations were not significant on all variables measured, except the total proto-zoal population (P<0.01). There were differences between the rumen fluid of cattle and those from the rumen fluid of buffalo on total bacterial population, DM and OM digestibilities (P<0.01). Ammonia and total VFA, and total bacterial popula-tion were increased at 3h incubation time (P<0.01). It is concluded that addition of crude curcin extracts from JCSM up to 3% (v/w) did not produced negative ef-fects on ration fermentability and digestibility, except for protozoal population. The greater numbers of bacteria in the rumen fluid of buffalo than those in the rumen fluid of cattle cause higher DM and OM digestibilities.