Longitudinal investigation of changes in the gut microbiome of chickens from birth to market

A total of 200 one-day-old Cobb chicks were used in this trial to select high and low feed efficiency chicken cohorts. Chicks were housed together during the brooding stage to ensure microbiota exchange through typical bird behavior, including coprophagy. After brooding stage, chicks were transferred into individual cages for growth. During the growing stage, feed intake and body weight of individual chickens were weighted weekly to determine growth performance including average daily gain, average daily feed intake, and feed conversion ratio. All chickens were fed a basal diet, and had free access to feed and water throughout the trial. At the end of the feeding trial, 30 chickens from 150 chicken cohorts were selected and divided into two groups: high feed efficiency (HF, n=15) chickens and low feed efficiency (LF, n=15) chickens based on their growth performances. To reduce the bias from inter-animal variation in the microbiota, fecal samples from the same broiler were collected weekly to investigate longitudinal changes in the gut microbiota of chickens from birth to market.