Exploring the Linkage Between Ruminal Microbial Communities on Postweaning and Finishing Diets and Their Relation to Residual Feed Intake in Beef Cattle

Abstract

Feed efficiency significantly impacts the economics of beef production and is influenced by biological and environmental factors. The rumen microbiota plays a crucial role in efficiency, with studies increasingly focused on its relationship with different rearing systems. This study analyzed 324 rumen samples from bulls and steers categorized as high and low efficiency based on residual feed intake. The animals were fed two diets (postweaning and finishing) and rumen samples were sequenced using a reduced representation sequencing (RRS) based approach. The results indicated that diet significantly affected microbial diversity and abundance. In postweaning diets, Actinomycetota, particularly Bifidobacterium, were prevalent, aiding carbohydrate fermentation. In contrast, Acetoanaerobium was identified in finishing diets, likely contributing to acetate production. Additionally, Bacteroides and Butyrivibrio were abundant during postweaning, known for fiber degradation and volatile fatty acid production. Notably, Prevotella and Fibrobacter succinogenes were associated with high feed intake and nutrient utilization, indicating their potential as microbial biomarkers. However, alpha diversity indices showed no significant relationship with feed efficiency, suggesting that diversity alone may not adequately reflect the complexity of feed efficiency phenotypes. These findings highlight the importance of diet and microbial interactions on feed efficiency and suggest further research to explore these microbial contributions to precision feeding strategies.

Keywords: Bos taurus; feed efficiency; microbiome.

Figure 1

Bar chart composition for phylum representation from different groups. Bar chart composition at the phylum level for the five groups analyzed. Each bar represents a sample and the different colors a different phylum. BPW: bulls in postweaning; SPW: steers in postweaning; SF: steers in finishing. The numbers refer to the year of the test.

Figure 2

Structure analysis for the composition from the different groups. NDMS plot of all the samples analyzed in the study. In light blue are the bulls (BPW) and in dark green and pink there are the steers, all on the postweaning diet for years 1 and 2 (SPW1 and SPW2). In dark blue and light green are the steers on the finishing diet, also for years 1 and 2, respectively, (SF1 and SF2).

Figure 3

Different alpha diversity indices for all the rumen sample groups. Richness, Shannon, and Simpson diversity indices from all groups of samples. Colors represent a group of samples. BPW: bulls in postweaning; SPW: steers in postweaning; SF: steers in finishing.

Figure 4

Archaea distribution between the postweaning and finishing diets. A box plot analysis of the six Archaea present in the samples in both diets. Colors represent the year of the RFI test (brown = Year 1 and green = Year 2).