AUTHOR=Wang Hanning , Meng Lingbo , Mi Lan 

TITLE=Effects of Leymus chinensis hay and alfalfa hay on growth performance, rumen microbiota, and untargeted metabolomics of meat in lambs

JOURNAL=Frontiers in Veterinary Science

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2023.1256903

DOI=10.3389/fvets.2023.1256903

ISSN=2297-1769

ABSTRACT=<sec id="sec1"><title>Objective</title><p>The objective of this study was to compare the effects of <italic>Leymus chinensis</italic> hay and alfalfa hay as the roughage on the rumen bacterial and the meat metabolomics in lambs.</p></sec><sec id="sec2"><title>Methods</title><p>Fourteen male lambs were randomly assigned to two dietary treatments (one group was fed with concentrate and <italic>Leymus chinensis</italic> hay; another was fed with concentrate and alfalfa hay) with seven replicates per treatment. The feeding experiment lasted for 60 days. Lambs were slaughtered at the end of the feeding experiment. Growth performance, carcass performance, and weights of various viscera were determined. The longissimus dorsi and rumen contents were collected for untargeted metabolomics and 16S rDNA amplicon sequencing analysis, respectively.</p></sec><sec id="sec3"><title>Results</title><p>The lambs fed with alfalfa hay showed a significantly increased in average daily gain, carcass weight, dressing percentage, loin-eye area, and kidney weight. Feeding <italic>Leymus chinensis</italic> hay and alfalfa hay diets resulted in different meat metabolite deposition and rumen bacterial communities in the lambs. The relative abundance of phyla <italic>Fibrobacteres</italic>, <italic>Bacteroidetes</italic>, and <italic>Spirochaetes</italic> were greater in the <italic>Leymus Chinensis</italic> hay group, while, the relative abundance of <italic>Firmicutes</italic>, <italic>Proteobacteria</italic>, <italic>Fusobacteria</italic>, and <italic>Verrucomicrobia</italic> were greater in the alfalfa hay group. Based on untargeted metabolomics, the main altered metabolic pathways included alanine, aspartate and glutamate metabolism, D-glutamine and D-glutamate metabolism, phenylalanine metabolism, nitrogen metabolism, and tyrosine metabolism. Several bacteria genera including <italic>BF31</italic>, <italic>Alistipes</italic>, <italic>Faecalibacterium</italic>, <italic>Eggerthella</italic>, and <italic>Anaeroplasma</italic> were significantly correlated with growth performance and meat metabolites.</p></sec><sec id="sec4"><title>Conclusion</title><p>Alfalfa hay improved growth performance and carcass characteristics in lambs. <italic>Leymus chinensis</italic> hay and alfalfa hay caused different meat metabolite deposition by modifying the rumen bacterial community. These findings will be beneficial to future forage utilization for sheep growth, carcass performance, and meat quality improvement.</p></sec>