Abstract
High grain diets offer more readily available fermentation by-products, which are used by ruminants for energy production; however, it increased risk for the development of ruminal acidosis. Hence, we evaluated the buffering capacity of six buffer agents and its effects on ruminal fluid in vitro. Ruminal fluid was collected before morning feeding from three ruminally fistulated Holstein Friesian cows (600 ± 47 kg body weight) served as inoculum. Corn meal (2.5g) with or without buffer agents (0.5g) were in vitro fermented and anaerobically incubated for 0, 6, 12, and 24 h. The buffer agents, bentonite, calcium carbonate, calcium oxide, sodium bicarbonate, sodium sesquicarbonate and processed coral, were served as treatments (T1 – T6), respectively while the unbuffered served as negative control (T7). Modified protocol was used to determine the buffering capacity of the treatments in rumen fluid. Titration analysis was performed to obtain the neutralizing and buffering capacity of the treatments. All analyses were carried out using SAS. Among the tested agents, calcium oxide obtained the highest buffering capacity value and had a significantly higher pH values (p<0.05) than the other treatments. Also, titration analysis showed that this compound had high values of neutralizing and buffering capacity. The total gas production was observed the highest for sodium bicarbonate and sodium sesquicarbonate (p<0.05) after 24 h of incubation. Consequently, these two treatments including calcium oxide also had the highest (p<0.05) individual and total volatile fatty acids (VFA) concentrations. Overall, calcium oxide, sodium bicarbonate and sodium sesquicarbonate stabilized ruminal acid-base status and improved in vitro rumen fermentation. Thus, supplementation of these compounds are potential buffering agents against ruminal acidosis.
Keywords: Buffering capacity, buffer agents, fermentation, in vitro, ruminal fluid