SRA

Objective of this study is to characterize the impact of an early life yeast supplementation and age on colon mucosa-associated bacteria and host immune function. A total of 20 Holstein bull calves born from May to August 2018 with a birth BW between 35 and 55 kg were used in this study and randomly assigned to a unique pen referring to one of the two dietary treatments for 7 days. Singlet calves naturally delivered were removed from their dam immediately after birth to avoid any contact. Calves received two meals of a standardized colostrum (HeadStart, Saskatoon Colostrum Co. Ltd., Saskatoon, SK, Canada) at 2 h (7% of birth BW, 180 g of IgG fed) and 12 h (3% of birth BW, 120 g of IgG fed). Calves were subsequently bottle-fed daily two meals of milk replacer (MR) at 0700 and 1900. Regardless of groups, ten calves were assigned to a treated group (SCB) and were supplemented throughout the experiment with the same daily quantity of 5 g of live SCB (ProTernative Milk; Levucell SB20 containing the Pasteur Institute CNCM I-1079 strain of Saccharomyces cerevisiae boulardii; Lallemand Animal Nutrition, Montreal, Quebec, Canada). The supplementation was added in the first colostrum feeding and subsequently in each MR morning feedings, which was expected to supply 10 Ã? 109 cfu of SCB per calf per day. The other ten calves (CON) did not received supplementation in any of their meals during the entire experiment. Colon tissue biopsies were taken within 2 h of life and 3 h after morning feed at d 5 of age according to the methodology developed by van Niekerk et al. (2018) that ensure suitable samples for 16s amplicon sequencing and RNA sequencing.