Hydrate sodium calcium aluminosilicate does not reduce rumen lipopolysacharide concentrations in cows

The efficacy of hydrate sodium calcium aluminosilicate (HSCAS) to reduce the concentrations of free lipopolysaccharide (LPS) in rumen fluid of cows was investigated. Six, rumen-fistulated crossbred Holstein, non-pregnant, dry cows were randomly assigned to three experimental rations in a study with a replicated 3 × 3 Latin square design with 28-d periods. During the first 20 days of each experimental period, cows were offered concentrate (5.4 kg dry matter; DM) without HSCAS and rice straw ad libitum. On day 21, cows were fasted for 12 h prior to commencement of a 7-d measurement period during which time cows were offered concentrate (10.5 kg DM) containing either 0, 5 or 10 g/kg of HSCAS and 1.5 kg DM rice straw. Rumen fluid was collected on days 1, 3 and 7 during the measurement period for analysis of pH, LPS and volatile fatty acids (VFA). Supplemental HSCAS did not affect the pH or the concentrations of total and individual VFA in the ruminal fluid. Mean postprandial rumen pH was reduced to values below 5.6 at all times. Rumen LPS concentrations significantly increased from day 1 to 7 during each measurement period with values ranging from 4489 to 104,000 EU/mL but they were not significantly affected by supplemental HSCAS.