Three sheep fitted with a ruminal cannula and an abomasal catheter were used to study water kinetics and absorption of VFA infused continuously into the rumen. The effects of changing VFA concentrations in the rumen by shifting VFA infusion rates were investigated in an experiment with a 3 x 3 Latin square design. On experimental days, the animals received the basal infusion rate of VFA (271 mm...

Two experiments were conducted to determine the effects of several essential oil active compounds on rumen microbial fermentation. In the first experiment, 4 doses (5, 50, 500, and 5,000 mg/L) of 5 essential oil compounds were evaluated using in vitro 24-h batch culture of rumen fluid with a 60:40 forage:concentrate diet (18% crude protein; 30% neutral detergent fiber). Treatments were control ...

The effect of rumen liquid volume, pH and concentration of volatile fatty acids (VFA) on the rates of absorption of acetic, propionic and butyric acids from the rumen was examined in lactating dairy cows. Experimental solutions introduced into the emptied, washed rumen comprised two different volumes (10 or 30 l), four levels of pH (4.5, 5.4, 6.3, 7.2) and three levels of individual VFA concent...

the objective of this study was to test whether the stimuli of osmotic pressure (op), vfa or ph in the omasum would affect the passage of digesta from the rumen and feed intake in sheep. five experements were carried out. different solutions with specific, op, vfa concentration and ph were infused into the omasal body. rumen digesta volumes and outflow rates (liquid and solid) were measured by ...

Simple titration methods certainly deserve consideration for on-site routine monitoring of volatile fatty acid (VFA) concentration and alkalinity during anaerobic digestion (AD), because of their simplicity, speed and cost-effectiveness. In this study, the 5 and 8 pH point titration methods for measuring the VFA concentration and carbonate system alkalinity (H2CO3*-alkalinity) were assessed and...

background: in recent years, dietary fat supplementation has become a common practice and fat supplemented diets have had variable effects on animal performance and carcass characteristics. objectives: this study was conducted to determine the effect of  increasing the levels of sesame oil on performance, rumen parameters and plasma lipid profile in finishing chal lambs. methods: eighteen male ...

The titrimetric method is used for on-site measurement of the concentration of volatile fatty acids (VFAs) in anaerobic treatment. In current practice, specific and interpolated pH-volume data points are used to obtain the concentration of VFA by solving simultaneous equations iteratively to convergence (denoted as SEq). Here, the least squares method (LSM) is introduced as an elegant alternati...

This paper reports on the development and verification of a new simple, rapid and accurate titration method suitable for on-site measurement of volatile fatty acids (VFA) and carbonate alkalinity in anaerobic reactors. The method takes into account the effects of the phosphate, ammonium, sulfate, and sulfide weak acid subsystems on titration results. The method involves eight pH observations an...

Changes in the total concentration of the volatile fatty acid (VFA) pool in the rumen were followed over a 24 hour period in 2 groups of sheep, 1 fed at 08h00 and the other twice daily at 08h00 and 20h00. Although similar maximum (143 and 147 meq/1) and average (100, 3 and 102, 1 meq/1) levels were found in the 12 and 24 h groups respectively, the twice daily feeding regimen resulted in a lower...

This study aimed to produce polyhydroxyalkanoates (PHAs) from organic wastes by mixed bacterial cultures using anaerobic-aerobic fermentation systems. Palm oil mill effluent (POME) was used as an organic source, which was cultivated in a two-step-process of acidogenesis and acid polymerization. POME was operated in a continuous flow anaerobic reactor to access volatile fatty acids (VFAs) for PH...