Analysis of the Rumen Microbiota of Beef Calves Supplemented During the Suckling Phase

Abstract

A study was conducted to examine the effects of supplementing beef calves during their suckling phase (popularly known as creep feeding) with supplements that contained or did not contain the enzyme xylanase. Forty-two cow-calf pairs were divided into three groups and assigned to one of three treatments for a period of 105 days, as follows: (1) No supplemental feed for calves (control; CON); (2) Corn and soybean meal-based supplement feed for calves (positive control; PCON); and (3) Same feed regimen as PCON with xylanase added to the supplement (enzyme; ENZ). After 105 days, out of the 42 calves participating in the study, 25 male calves were randomly selected (8 from CON, 9 from PCON, and 8 from ENZ) and samples of their forestomach were collected by esophageal tubing. Immediately after this procedure, all calves were weaned, commingled, and placed in a common post-weaning diet for 4 weeks. At the end of this period, ruminal fluid was once again collected from the same 25 calves. All samples were subjected to DNA extraction and 16S rRNA gene sequencing. At weaning, most of the alpha diversity indexes were greater in CON; however, no differences ( P ≥ 0.23) in alpha diversity were observed in samples collected 4 weeks after weaning. Regardless of treatment, 2 phyla – Bacteroidetes and Firmicutes – comprised approximately 80% of the total bacterial abundance of samples collected on both days. At the genus level, an effect of diet ( P = 0.02) was observed for Prevotella in the samples collected at weaning; however, no differences were detected in the samples collected 4 weeks after weaning. Calf average daily gain (ADG) during the 105-day creep feeding trial tended ( P = 0.09) to be greater in the groups that received supplementation, with the greatest numerical value observed in ENZ. Moreover, there was a positive correlation (ρ = 0.43; P = 0.03) between ADG and abundance of Prevotella , indicating the importance of this bacterial group for ruminants. In summary, most of the significant differences found in this study were detected at weaning, and the majority of them disappeared 4 weeks after the calves were weaned and commingled.

Comparison of the ruminal and fecal microbiotas in beef calves supplemented or not with concentrate

“…As stated before, Prevotella was the most abundant genus detected in the ruminal samples, and its average abundance was greater in the creep fed calves. Previous research from our group [17] also observed that the presence of Prevotella was increased in the rumen of creep fed calves. That study also identified a positive correlation between abundance of Prevotella and calf average daily gains.…”

“…The complete Illumina library was purified with SPRI-beads (1:1 ratio) and sequenced on an Illumina MiSeq using a v3 600 cycle kit (Illumina, San Diego, CA) at the Georgia Genomics and Bioinformatics Core. Negative controls were used throughout extraction and PCR procedures, and used KAPA reagents (KAPA Biosystems, Wilmington, MA) as described in detail in a previous study [17].…”

Evaluation of the Fecal Bacterial Communities of Angus Steers With Divergent Feed Efficiencies Across the Lifespan From Weaning to Slaughter

“…After overnight storage, the samples were transported to the Georgia Genomics and Bioinformatics Core ( https://dna.uga.edu ) for library preparation and 16S rRNA gene sequencing. The library preparation included PCR replications using the forward primer: S-D-Bact-0341-b-S-17 (5′-CCTACGGGNGGCWGCAG-3′) and reverse primer: S-D-Bact-0785-a-A-21 (5′-GACTACHVGGGTATCTAATCC-3′) ( 13 , 14 ). PCR conditions were: initial denaturation at 95°C for 3 min, followed by 25 cycles of 95°C for 30 s, annealing at 55°C for 30 s, extension at 72°C for 30 s, and then a final elongation step at 72°C for 5 min.…”

The Impact of Pre-Slaughter Fasting on the Ruminal Microbial Population of Commercial Angus Steers

“…Upon arrival at the slaughter facility, rumen fluid was individually collected from all steers following the procedures described in Lourenco et al [18]. Briefly, this procedure utilized esophageal tubing and a perforated metal probe, which is attached to an electric vacuum pump for collection of the ruminal contents.…”