Effect of supplementation of various fermentable carbohydrate sources in sorghum straw-gliricidia mixed diet on fermentation kinetics measured using in vitro gas production

Abstract

Supplementation of fermentable carbohydrate in crop by product-based diet is expected to improve the fermentability and reduced methane production. The study evaluated supplementation of various fermentable carbohydrate in sorghum straw-gliricidia mixture basal diet. Sorghum straw-gliricidia mixture was supplemented either with ground corn grain, rice bran or sorghum grain at 10% of DM basal diet. Treatment diets evaluated were: Sorghum + gliricidia leaf meal (Control); Control + 10% ground corn grain (Corn grain); Control + 10% rice bran (Rice bran); Control + 10% sorghum grain (Sorghum). Sorghum straw was chopped and ground then mixed with gliricidia leaf meal at ratio 60:40% DM. The sample was incubated for 48 hours, gas production was recorded at 4, 8,12, 16, 24, 36 and 48 hours. Rumen fluid for medium incubation was collected from sheep fed elephant grass basal diet. Supplementation of rice bran lowered (P<0.05) gas production from insoluble fraction of the diet compared to maize. Rice bran and sorghum decreased gas production at 48 h incubation compared to control (P<0.05). Sorghum supplementation decreased CH4 production. It can be concluded that fermentable carbohydrate supplementation from sorghum grain to sorghum straw-gliricidia mixture reduced percentage of methane production.