Direct-fed microbial supplementation influences the bacteria community composition of the gastrointestinal tract of pre- and post-weaned calves

Abstract

This study investigated the effect of supplementing the diet of calves with two direct fed microbials (DFMs) (Saccharomyces cerevisiae boulardii CNCM I-1079 (SCB) and Lactobacillus acidophilus BT1386 (LA)), and an antibiotic growth promoter (ATB). Thirty-two dairy calves were fed a control diet (CTL) supplemented with SCB or LA or ATB for 96 days. On day 33 (pre-weaning, n = 16) and day 96 (post-weaning, n = 16), digesta from the rumen, ileum, and colon, and mucosa from the ileum and colon were collected. The bacterial diversity and composition of the gastrointestinal tract (GIT) of pre- and post-weaned calves were characterized by sequencing the V3-V4 region of the bacterial 16S rRNA gene. The DFMs had significant impact on bacteria community structure with most changes associated with treatment occurring in the pre-weaning period and mostly in the ileum but less impact on bacteria diversity. Both SCB and LA significantly reduced the potential pathogenic bacteria genera, Streptococcus and Tyzzerella_4 (FDR ≤ 8.49E-06) and increased the beneficial bacteria, Fibrobacter (FDR ≤ 5.55E-04) compared to control. Other potential beneficial bacteria, including Rumminococcaceae UCG 005, Roseburia and Olsenella, were only increased (FDR ≤ 1.30E-02) by SCB treatment compared to control. Furthermore, the pathogenic bacterium, Peptoclostridium, was reduced (FDR = 1.58E-02) by SCB only while LA reduced (FDR = 1.74E-05) Ruminococcus_2. Functional prediction analysis suggested that both DFMs impacted (p < 0.05) pathways such as cell cycle, bile secretion, proteasome, cAMP signaling pathway, thyroid hormone synthesis pathway and dopaminergic synapse pathway. Compared to the DFMs, ATB had similar impact on bacterial diversity in all GIT sites but greater impact on the bacterial composition of the ileum. Overall, this study provides an insight on the bacteria genera impacted by DFMs and the potential mechanisms by which DFMs affect the GIT microbiota and may therefore facilitate development of DFMs as alternatives to ATB use in dairy calf management.

Effect of milk feeding strategy and lactic acid probiotics on growth and behavior of dairy calves fed using an automated feeding system1

“…However, this does not necessarily mean there are no benefits of feeding probiotics to calves receiving higher milk allowances; for instance, probiotics might encourage calves to visit the calf starter bunk in smaller meals rather than eating calf starter in larger meals after weaning as did calves receiving the placebo. Speculatively, our calves may have benefited post-weaning from probiotic supplementation during the milk feeding period since probiotics stabilize intestinal microflora post-weaning (Bridget et al, 2018). It is possible that additional visits to solid feed were expressed in a more stable intestinal environment, though we cannot confirm this in our study.…”

Microbial Inoculum Composition and Pre-weaned Dairy Calf Age Alter the Developing Rumen Microbial Environment

“…In agreement with previous studies, the rumen bacterial community structure and composition did change with calf age (Rey et al, 2014; Dias et al, 2017; Dill-McFarland et al, 2017). Direct-fed microbial supplementation did not impact bacterial alpha diversity measures in pre- or post-weaned calves and bacterial communities clustered by age rather than by treatment (Fomenky et al, 2018). When bacteria naturally established in the rumen the communities clustered by age, however, the Shannon diversity index did not change (Rey et al, 2014).…”

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

“…Only a limited number of studies have performed direct comparisons between the microbiotas of the rumen and the feces in the same animals [21,22,23,24,25]. Additionally, this kind of comparison in beef calves is particularly scarce.…”