Abstract
Twenty young intact Menz-type male sheep were assigned to four levels of leucaena (Leucaena leucocephala cv. Peru) supplementation to chick pea haulm fed ad libitum: 0 (treatment A), 100 (B), 200 (C), and 300 (D) g day-1 head-1 . Water and mineral lick were offered free choice. Dry matter digestibility, intake, body weight gain, N balance, rumen ammonia concentration, and molar proportions of volatile fatty acids (VFA) were determined. Body weight gains increased from 59 to 87 g day-1 with increased leucaena leaf supplementation. Digestibility increased by 7 .0, 6.6, and 9.6 percentage units over the control diet when leucaena was offered at levels of 100, 200, and 300 g head-1 day-1, respectively. The concentrations of ammonia with treatments C and D were consistently higher than 20 mg 100-ml-1 of rumen fluid at all times, but this high ammonia level was observed with treatment B only at 4 h after feeding. The optimum VFA production time was delayed with more than 200 g of leucaena leaf and the total VFA production declined when more than 100 g was fed. However, the rate of protein and carbohydrate degradation seemed to be better synchronized in treatment B than in C and D. The rate of protein degradation was faster than carbohydrate with treatments C and D. The percentages of N retained were similar for the supplemented groups, despite differences in apparently absorbed N and in dietary N concentration. This suggests insufficient energy (glycogenic substances) supply for efficient retention of N in the rumen and at tissue level. It is suggested that split feeding of leucaena leaf hay at the 200-g and 300-g levels might lead to more efficient utilization of chick pea haulm, or additional energy supplementation may be required at the higher levels of leucaena supplementation.
