Feeding an unsalable carrot total-mixed ration altered bacterial amino acid degradation in the rumen of lambs

Rumen-Degradable Starch Improves Rumen Fermentation, Function, and Growth Performance by Altering Bacteria and Its Metabolome in Sheep Fed Alfalfa Hay or Silage

Alfalfa silage due to its high protein can lead to easier feeding management, but its high proportion of rumen-degradable protein can reduce rumen nitrogen utilization. Nevertheless, increasing dietary energy can enhance ruminal microbial protein synthesis. Thirty-two Suffolk female sheep were used in this study, with a 2 × 2 factorial arrangement of treatment. The four treatments were a combination of two forage types (alfalfa hay; AH vs. alfalfa silage; AS) and two rumen-degradable starch levels (low RDS; LR vs. high RDS; HR) with a 15 d adaptation and 60 d experimental period. The rumen content and rumen epithelium samples were collected after slaughter. Feeding AS increased the rumen isobutyrate, valerate, ammonia-N (NH3-N) concentration, urase activity, and papillae height (p < 0.05) and reduced the feed to gain (F:G), rumen bacterial protein (BCP), rumen lactic acid concentration, and papillae width (p < 0.05) of sheep. Increased RDS in the diet improved the daily matter intake, average daily gain, and rumen weight, reduced the F:G, and enhanced the rumen nitrogen capture rate by decreasing total amino acids and the NH3-N concentration to increase BCP, aquaporins 3 gene, and protein expression. The rumen microbiota also changed as the HR diet reduced the Chao index (p < 0.05). The metabolomics analysis showed that feeding AS upregulated the rumen tryptophan metabolism and steroid hormone biosynthesis, while the purine metabolism, linoleic acid metabolism, and amino acid biosynthesis were downregulated. Furthermore, increased RDS in the diet upregulated rumen lysine degradation and sphingolipid metabolism, while aromatic amino acid biosynthesis was downregulated. Additionally, the correlation analysis results showed that ADG was positively correlated with 5-aminopentanoic acid, and three microorganisms (unclassified_f__Selenomonadaceae, Quinella, Christensenellaceae_R-7_group) were positively correlated with the rumen isobutyrate, valerate, NH3-N concentration, urase activity, tryptophan metabolism, and steroid hormone biosynthesis and negatively correlated with linoleic acid metabolism and amino acid biosynthesis in sheep. In summary, increased RDS in the diet improved the growth performance and rumen N utilization and reduced bacterial diversity in sheep. The alfalfa silage diet only increased feed efficiency; it did not affect growth performance. Additionally, it decreased rumen nitrogen utilization, linoleic acid, and amino acid biosynthesis. Nevertheless, there were limited interactions between forage and RDS; increased RDS in the AS diet enhanced the nitrogen capture rate of rumen microorganisms for alfalfa silage, with only slight improvements in the purine metabolism, linoleic acid, and amino acid synthesis.

Multiomics of yaks reveals significant contribution of microbiome into host metabolism

An intensive feeding system might improve the production cycle of yaks. However, how intensive feeding system contributes to yak growth is unclear. Here, multi-omics, including rumen metagenomics, rumen and plasma metabolomics, were performed to classify the regulatory mechanisms of intensive feeding system on yaks. Increased growth performance were observed. Rumen metagenomics revealed that Clostridium, Methanobrevibacter, Piromyces and Anaeromyces increased in the intensively fed yaks, contributing to amino acid and carbohydrate metabolism. The grazing yaks had more cellulolytic microbes. These microbiomes were correlated with the pathways of "Alanine aspartate and glutamate metabolism" and "Pyruvate metabolism". Intensive feeding increased methane degradation functions, while grazing yaks had higher methyl metabolites associated with methane production. These rumen microbiomes and their metabolites resulted in changes in plasma metabolome, finally influencing yaks' growth. Thus, an intensive feeding system altered the rumen microbiome and metabolism as well as host metabolism, resulting in improvements of yak growth.

Ruminal microbiota-host crosstalks promote ruminal epithelial development in neonatal lambs with alfalfa hay introduction

Ruminal microbiota is gradually established after birth, while microbiota maturation could be highly diverse because of varied solid dietary accessibility. However, how the ruminal microbiota accreted from postnatal hay diets alters rumen epithelial development, and how this affects animal health remains largely unknown. Here, neonatal lambs were introduced to starchy corn-soybean starter or corn-soybean starter + alfalfa hay (AH) to investigate the influences of early life ruminal microbiome on rumen epithelial development using integrated 16s rRNA sequencing-metagenome-transcriptome approaches. The results showed that AH introduction elevated average daily weight gain, rumen weight and volume, rumen epithelial papillae length, and rumen muscle layer thickness. Meanwhile, the relative abundance of fibrolytic bacteria (Christensenellaceae R-7 group, Prevotellaceae UCG-001, and Succinivibrio), acetate producer (Acetitomaculum and Mitsuokella), and propionate producer Succiniclasticum was increased in the rumen content by AH supplementation (P < 0.05). Moreover, AH introduction decreased the relative abundance of total CAZymes, CBM, and GH and increased the abundance of KO genes related to volatile fatty acid (VFA) generation in the rumen content. AH lambs had a higher relative abundance of Succiniclasticum, Megasphaera, Succinivibrio, and Suttonella (P < 0.05), while a lower relative abundance of Cloacibacillus, Desulfovibrio, Dialister, Intestinimonas, Parabacteroides, and Pseudoscardovia (P < 0.05) in the rumen epithelial samples. Furthermore, these alterations in ruminal microbial structure and function resulted in ruminal epithelial cell proliferation and development pathways activation. In summary, AH introduction benefited ruminal fiber degradation and VFA generation bacteria colonization and promoted ruminal epithelial development. These findings provide new insights into ruminal microbial-host interactions in the early life.IMPORTANCEWhile it is established that a fiber-rich diet promotes rumen development in lambs, further research is needed to investigate the precise response of rumen microbiota and epithelium to high-quality alfalfa hay. Here, we observed that the inclusion of alfalfa hay led to a discernible alteration in the developmental trajectory of the rumen. Notably, there was a favorable shift in the rumen's volume, morphology, and the development of rumen papillae. Furthermore, ruminal microbial structure and function resulted in ruminal epithelial cell proliferation and development pathways activation, collectively provide compelling evidence supporting the capacity of alfalfa hay to enhance rumen development and health through ruminal micrbiota-host crosstalks. Our findings elucidate the functional response of the rumen to alfalfa hay introduction, providing new insights into strategies for promoting healthy development of the rumen in young ruminants.