Effect Of Thiamin On Metabolism Of The Rumen And Its Consquences To Subacute Ruminal Acidosis In Goats

In this study, the reasonable amount of thiamine additives was selected in vitro. Six healthy XuHuai wethers fitted with permanent ruminal cannulas were induced SARA by feeding concentrate daily in gradually increasing feeding regime.The experimental animals were fed thiamin into diets when animals were in SARA period. To investigate influence of thiamin on the internal environment and metabolism of rumen and attempt to supply some references for the further study of Thiamin in the rumen.The results of this research as followed:In the first experiment, the effect of thiamin on the rumen fermentation and activity under high-concentrate diet was investigated in vitro. The in vitro culture were conducted using semi-pure diet consisted of a mixture of15.7g milled filter paper,9.2g pectins,4.3g xylan,61.6g wheat starches and9.2g soluble starches, the concentrate/forage ratio is80:20. The results showed that pH in culture fluid increased in case high-concentrate diet when adding thiamin; there were no significant differences in NH3-N concentration among five levels of thiamin; the concentrations of lactate、acetate and total VFAs were decreased, the concentrations of propionate and butyrate was increased, as well as the acetate/propionate ratio decreased when adding thiamin. The addition of160mg/kg and240mg/kg thiamin was better. It was also found that amylase activity was decreased, but cellulose enzyme activity was increased in the culture,160mg/kg treatment of activity of xylanase was higher than the control.In the second experiment, the reasonable amount of thiamine additives was selected under high-concentrate diet in vitro. The in vitro culture was same as in test1. The adding level of thiamin were designed as Omg/kg、160mg/kg、240mg/kg. The results showed that Thiamin increased pH and the total concentration of thiamin; the concentration of the lactate and the activity of thiamine enzymes were decreased. When addition of thiamin is240mg/kg, the effect of fermentation is the best In the third experiment, study on the metabolism of the rumen in Goats suffered from subacute ruminal acidosis. Six healthy XuHuai wethers fitted with permanent ruminal cannulas were fed suecessively four kind of diets with different NFC/NDF levels,1.43(Ⅰ)、1.79(Ⅱ).2.27(Ⅲ) and3.14(Ⅳ) during the40-day measurement period, respectively. The results showed that rumen pH decreased significantly with increase of dietary NFC/NDF. Rumen VFA concentrations increased with increase of dietary NFC/NDF levels, propionate concentration increased, and butyrate concentration increased significantly. While acetate concentration and A/p decreased in case of SARA was induced. Lactate concentration remained at low levels. Improving dietary NFC/NDF levels led to gradual increase of concentrations of histamine and endoxin in rumen fluid, and concentrations of histamine and endoxin in rumen increased significantly with the development of SARA. The total concentration of thiamin decreased and the activity of thiamine enzymes increased.In the fourth experiment, effect of thiamin on metabolism of the rumen in goats suffered from subacute ruminal acidosis. Six goats were induced in SARA by a feeding regime of increasing concentrate daily in gradually, the animals were randomly divided into two groups, the animals were fed with the combined additives in test group and fed without additives in control group. The results showed that thiamin increased pH during induced SARA period. The concentrations of lactate. acetate and total VFAs were decreased, the concentrations of propionate and butyrate was increased. Thiamin led to gradual decrease of concentrations of histamine in blood and rumen fluid, there had no significant effect on endoxin in blood and rumen fluid. The total concentration of thiamin increased and the activity of thiamine enzymes decreased.