16S rRNA sequencing data of ruminal bacterial profiles under grain-diet and hay-diet feeding patterns at six different timepoints in sheep

In order to investigate the diurnal oscillations of ruminal bacteria, and their responses to the changes in different feeding patterns, we conducted an animal experiment by feeding the sheep ad libitum with a hay-based diet (50% of alfalfa hay and 46% of oats hay) and a grain-based diet (45% of corn meal and 11% of soybean meal) for 30 days, and ruminal fluid samples were collected at six different timepoints from T2 to T22 in one day, and the composition and diversity of the bacterial communities in rumen microbiomes of the sheep in the Grain-diet and Hay-diet groups at different timepoints were analyzed through 16S rRNA sequencing. Overall design: A total of 16 healthy sheep with similar body weight (nearly 65 kg) and aged around 3.5 years old were selected in this study. All sheep were placed with permanent rumen fistula at 2 years old. The inner diameter of the fistula was 4 cm. Prior to the animal trial, all sheep were maintained under the same farming conditions in individual tie-stalls and fed a hay-based diet (Hay-diet group) ad libitum for 14 days to ensure stable feeding. Then, 8 sheep were randomly divided into the Hay-diet group and continued to feed hay-based diet. The other 8 sheep were shifted to feed on a grain-based diet (Grain-diet group) with a forage/concentrate of 40:60 (dry matter basis). The feeding trial lasted for 30 days, adequate feed was provided daily at 8 am, and all sheep had free access to feed and water throughout the study. All sheep were vaccinated and had no history of antimicrobial agents (antibiotics, antifungals, or antivirals) administration or clinical signs of diseases. Fasting was not required for the sheep before sampling, and the ruminal fluid samples of 16 sheep were collected from 2:00 to 22:00 at a 4-hour interval (a total of 6 timepoints were selected at T2, T6, T10, T14, T18, and T22) on sampling day. A 50 mL rumen fluid sample was collected from the rumen fistula, samples were then filtered through four layers of sterile cheesecloth and stored at -80°C for 16S rRNA sequencing.