The effect of 4% dietary inclusion of Himanthalia elongata seaweed and seaweed extract on the microbiome of late-lactation dairy cows.

The dietary provision of seaweed to ruminants has the potential to reduce methane and ammonia emissions by influencing the rumen microbiome. In this study 15 late lactation Holstein-fresian dairy cows were blocked into three groups of five animals in a 3x3 latin square design. The animals were fed one of three experimental diets (Control, T1: 4% HE Extract, T2; 4% HE whole) for 21 days before rotating onto the next experimental diet. On day 0 of period 1 and then on day 21 of each period rumen fluid was collected by esophageal tube extraction. The rumen fluid was frozen in liquid nitrogen before being stored at -80 degrees Celsius. The DNA extraction was carried out using the Qiagen Pro Soil kit and kit instructions were followed. The sequencing was performed by the GTCU at Queens University Belfast.