Toleransi Mikroba Rumen Kambing dan Domba Terhadap Penambahan Ekstrak Kasar Antinutrien Bungkil Biji Jarak Pagar (Jatropha Curcas L.) ke Dalam Ransum Berdasarkan Fermentabilitas Dan Kecernaan In Vitro*

Abstract

Toleration of microbes from the rumen fluid of goat and sheep to the addition of antinutrient crude extract of Jatropha (J.) Clircas L. seed meal was evaluated based on in vitro fermentability and digestibility study. Antinutrient crude extract of J. curcas L. seed meal was isolated to contain kursin as one important antinutrientltoxin of J. curcas L. seed meal. Fermentability and digestibility experiments were carried out following the two stages of Tilley and Terry (1963) method that was modified by Sutardi (1979). Fermentability experiment was conducted in a 2x4x2 factorial randomised block design; factor A was source of rumen fluid microbes (goat and sheep), factor B was addition levels of antinutrient crude extract of J. curcas L. seed meal to ration (0, I, 2 and 3 % v/w total ration), and factor C was incubation period (0 and 3 hour). A factorial randomised block design (2x4) was also used to carry out digestibility study with the treatments were source of rumen fluid (factor A) and addition levels of anti nutrient crude extract of J. curcas L. seed meal to ration (factor B). In both studies, rumen fluids from three goats and sheep were used as the block. Variables measured were total VFA and ammonia concentrations, total bacterial and protozoal populations, and dry matter (OM) and organic matter (OM) digestibility coefficients. Data were analysed with analysis of variance and differences among treatments were examined with contrast orthogonal. The results demonstrated that source of rumen fluids affected total bacterial population (P<O.OI), and DM and OM digestibilitj coefficients (P<O.05). Rumen fluid of goat had greater total bacterial population than sheep, but it digested DM and OM at a lower extent. The effect of interaction between rumen fluid sources and incubation time was significant (P<O.O 1) on total protozoal population; the population in rumen fluid of sheep decreased at 3 h incubation time, but such decrease did not occur in rumen fluid of goat. There were no significant effects of rumen fluid sources on total VF A and ammonia concentration. No significant effects of addition levels of antinutrient crude extract, incubation time, and interactions among factors on all variables measured, except the effect of incubation time on ammonia concentration (P<O.O I). It is concluded that microbes from the rumen fluid of goat and sheep are different in its tolerant to antinutrient crude extract of J. curcas L. seed meal added to ration up to 3% v/b.