Effect of beta-glucan supplementation on feed intake, digestibility of nutrients and ruminal fermentation in Thai...

This study was conducted to evaluate the effect of ß-glucan on feed intake, digestibility of nutrients and ruminal fermentation in Thai native beef cattle that were fed low-quality roughage. Four, Thai native beef cattle with initial body weight (BW) of 100 ± 20.0 kg were randomly assigned according to a 4 × 4 Latin square design to receive four treatment by ß-glucan at 0, 1.6, 3.1 and 4.7 g/day respectively. Supplementation of ß-glucan at 0-4.7 g in cattle did not affect the intake of DM, OM, CP, NDF or ADF. However, supplementation with ß-glucan significantly improved rice straw intake (g/kg BW^0.75 ), compared to the nonsupplemented group (p < 0.05), so rice straw intake was higher than in the group without ß-glucan supplementation. In addition, total feed intake increased with the higher level of ß-glucan supplementation. The estimated energy intake was not altered by ß-glucan supplementation (p > 0.05). The experimental diet had no effect (p > 0.05) on the apparent digestibility of DM, OM, NDF or ADF. However, the digestibility of CP was significantly different among treatment and supplementation at 4.7 g/day ß-glucan which was the highest level (63.2%) among all diets. ß-glucan supplementation did not affect rumen pH, temperature or ruminal NH₃ -N concentration. In addition, blood urea-N levels were similar among experimental groups. The population of protozoa at 4 hr post-feeding increased along with ß-glucan supplementation and was highest at 4.7 g of ß-glucan. Based on this experiment, it could be concluded that supplementation of ß-glucan at 4.7 g improved rice straw intake, as well as total intake and digestibility of CP in Thai native beef cattle.