Abstract 99

Ahn,-JH; Robertson,-BM; Elliott,-R; Gutteridge,RC; Ford,-CW

Department of Agriculture, University of Queensland, St. Lucia, Qld 4067, Australia.

Animal-Feed-Scienceand-Technology. 1989, 27: 1-2, 147-156; 25 ref.

The in sacco digestibilities of DM and nitrogen content of the leaf material from 12 species of tropical browse legumes were measured in rumen-fistulated goats fed on a diet of rice straw supplemented with lucerne chaff. Freeze-dried samples of Albizia lebbek, Enterolobium cyclocarpum, Samanea saman and Sesbania sesban did not contain condensed tannins. These browse species also exhibited high digestibilities of DM and N. Highest condensed tannin contents (vanillin-HCl method) were in Calliandra calothyrsus (11.07%) and Codariocalyx gyroides (7.12%). In species which contained tannins, however, there was poor correlation between N digestibility and total condensed tannin content (measured either by vanillin-HCl or butanol-HCl assay). Drying the browse at 60 ø C in a forced-draught oven resulted in variable losses in both total phenolics and condensed tannin content in all species. In particular, Gliricidia sepium and Tipuana tipu lost all apparent tannin content during oven drying. Lowest digestibilities of N ( < 43%) were observed in Acacia aneura, A. angustissima, Albizia chinensis and C. calothyrsus. Oven drying of these species significantly increased N digestibility.