Study on the Production,Absorption and Passage of Propionate in the Sheep Rumen with Indirect Method

A pulse continuous buffer solution with non labeled propionate was introduced to the rumen of the sheep to reach rumen steady state,and basal rumen propionate production rate (mmol/h) from the fermentation of dietary carbohydrate in the rumen,disappearance and passage of propionate in the rumen,disappearance of propionate in the omasum,abomasum and small intestine,and some rumen liquid phase indexes were investigated after propionate production rate was elevated by infusing different levels of non labeled propionate solution.The results indicated that basal propionic acid production rate was 22 4 mmol/h,and the pool size of propionate was 51 94 mmol which was 9 6% of propionic production per day in the sheep fed a 54% ground hay 46% corn based concentrate diet eight times a day at maintenance energy level,and some parameters for rumen steady state condition were found as follows:CV of fluid pH was 0 5%,CV of propionic concentration was 6% and CV of Co concentration of label was less then 5%.Ruminal disappearance of propionate was linearly related to its rate of production (P0 01),but the fraction of total production from 68% to 71% disappeared from the rumen when the production rate of propionic acid was elevated from 37 14 mmol/h to 145 07 mmol/h.Conversely,approximately 29%～32% passed out the rumen to the remainder parts of the stomach and intestines.It was suggested that more than 96% propionate flowed out the rumen was absorbed in the omasum and abomasum,and the remainder 4% entered into the small intestine.At the same time a series of relationship equations were established based on the data of the production rate of propionate (PROD prop ,mmol/h) in the rumen and other indexes obtained.