Effects of non-fiber carbohydrates sources on ruminal fermentation and nutrient utilization in vitro

【Objective】The study investigated the effects of non-fiber carbohydrates(NFC)from different sources on ruminal fermentation and nutrient utilization in vitro.【Method】Alfalfa-soybean meal with 4different NFC sources(corn starch,sucrose,fructo oligosaccharide,and poly fructose)was designed.Rumen fluid was obtained from four ruminally fistulated goats fed for 60dto ferment the four diets.The ruminal fermentation fluid pH,gas,production rate of total volatile fatty acid(TVFA),activities of xylanase and carboxymethyl cellulose enzymes,methane production,and the apparent disappearance rates of dry matter(DM)and neutral detergent fiber(NDF)were determined.【Result】Apparent disappearance rates of DM and NDF of 4NFC sources were significantly/extremely significantly different,and both showed the highest in corn starch group.Apparent disappearance rate of NDF was low.Sources of NFC extremely significantly affected TVFA production rate,and the maximum and minimum values occurred in the poly fructose group and the corn starch group,respectively.Ratio of acetate to TVFA was the lowest in corn starch group,while ratios of butyrate,isobutyric and isovaleric to TVFA were greater than other treatments.Gas production rate of corn starch group and methane production rate of poly fructose group were similar to sucrose group,but significantly/extremely significantly greater than other groups. Effects of NFC sources on in vitro ruminal fermentation fluid pH,activities of xylanase and carboxymethyl cellubse enzymes,the molar ratios of acetic acid and valeric acid to TVFA,and mass ratio of methane to TVFA were not significant.【Conclusion】Compared with sucrose,fructo oligosaccharide and poly fructose groups,the apparent disappearance rates of diet DM and NDF,and molar ratio of acetate to TVFA in starch group were extremely significantly increased,while TVFA production rate and molar ratio of propionate to TVFA were extremely significantly decreased.Compared with fructose and fructo oligosaccharidepoly treatments,poly fructose group had higher fiber degradation rate and TVFA production rate.