Lignocelluloytic activities and composition of bacterial community in the camel rumen

Alfalfa hay substitution for wheat straw improves beef quality via rumen microflora alteration

The use of high-quality roughage to improve beef quality has become an important issue in China, as the country has become the world's largest beef consumer. This study aimed to evaluate the effects of different forage qualities (wheat straw vs alfalfa hay) on Simmental crossbreed cattle's meat quality, rumen fermentation and microbiota. AHG (Alfalfa hay group) improved the ADFI (Average daily feed intake) and ADG (Average daily gain) of the beef cattle, meat-to-bone ratio and EE (Ether extract). The C18:3n3 and C20:3n3 composition of LD in AHG was significantly higher than WSG. An increase in the relative abundance of Firmicutes and a decrease in Bacteroidetes was observed. AHG resulted in higher relative abundance of Saccharomonospora, Streptomyces. A negative correlation between Treponema and muscle PUFA was noticed. Prevotella was negatively correlated with starch and sucrose metabolism. In conclusion, current study demonstrates that feeding alfalfa hay can raise meat quality by altering the rumen microbiota, providing valuable information for the application of alfalfa hay in beef cattle breeding.

Functional and phylogenetic analyses of camel rumen microbiota associated with different lignocellulosic substrates

Rumen microbiota facilitates nutrition through digestion of recalcitrant lignocellulosic substrates into energy-accessible nutrients and essential metabolites. Despite the high similarity in rumen microbiome structure, there might be distinct functional capabilities that enable different ruminant species to thrive on various lignocellulosic substrates as feed. Here, we applied genome-centric metagenomics to explore phylogenetic diversity, lignocellulose-degrading potential and fermentation metabolism of biofilm-forming microbiota colonizing 11 different plant substrates in the camel rumen. Diversity analysis revealed significant variations in the community of rumen microbiota colonizing different substrates in accordance with their varied physicochemical properties. Metagenome reconstruction recovered genome sequences of 590 bacterial isolates and one archaeal lineage belonging to 20 microbial phyla. A comparison to publicly available reference genomes and rumen metagenome-assembled genomes revealed that most isolates belonged to new species with no well-characterized representatives. We found that certain low abundant taxa, including members of Verrucomicrobiota, Planctomycetota and Fibrobacterota, possessed a disproportionately large number of carbohydrate active enzymes per Mb of genome, implying their high metabolic potential to contribute to the rumen function. In conclusion, we provided a detailed picture of the diversity and functional significance of rumen microbiota colonizing feeds of varying lignocellulose composition in the camel rumen. A detailed analysis of 591 metagenome-assembled genomes revealed a network of interconnected microbiota and highlighted the key roles of certain taxonomic clades in rumen function, including those with minimal genomes (e.g., Patescibacteria). The existence of a diverse array of gene clusters encoding for secondary metabolites unveiled the specific functions of these biomolecules in shaping community structure of rumen microbiota.

Effect of barley straw and Egyptian clover hay on the rumen fermentation and structure and fibrolytic activities of rumen bacteria in dromedary camel

Background and Aim: Understanding the regulations of rumen microbiota and their fibrolytic capabilities under different forages are essential to improve rumen fermentation and animal feed efficiency. This study aimed to evaluate the changes in the rumen fermentation and the structure and fibrolytic activities of rumen bacteria in camels fed barley straw and Egyptian clover hay. Materials and Methods: Three fistulated camels were fed a diet containing barley straw for 30 days; then transitioned to a diet containing Egyptian clover hay for 30 days. In addition, bacterial media enriched with xylan and different cellulose sources, namely, filter paper, wheat straw, and alfalfa hay, were used to evaluate the ability of camel rumen bacteria to produce xylanase and cellulase enzymes. Results: The camel group fed Egyptian clover hay showed higher crude protein intake, rumen ammonia, total volatile fatty acids, and acetic acid. Moreover, the camel group fed barley straw showed higher neutral detergent fiber intake, rumen pH, and propionic and butyric acids. Principal component analysis showed that bacterial communities were separated based on the forage type. Forage type affected the composition of rumen bacteria and most of the bacterial community was assigned to phylum Bacteroidetes and Firmicutes. Egyptian clover hay diet increased the proportions of genus Prevotella and Ruminococcus; while fed barley straw diet increased the Butyrivibrio, RC9_gut_group, and Fibrobacteres. The bacterial culture of the Egyptian clover hay fed group produced the greatest xylanase and the bacterial culture of the barley straw fed group produced the maximum cellulase. Conclusion: Egyptian clover hay is recommended to feed camels in intensive production. Moreover, the bacterial community in the camel rumen is a promising source of lignocellulolytic enzymes.