Metagenomical comparison of the microbial load colonizing alfalfa hay and gum tragacanth (Astragalus glycyphyllos) in ruminants

<p class="journal_abstract" style="box-sizing: inherit; margin-bottom: 1.5rem; padding: 0px; font-size: 15px; line-height: 1.6; text-rendering: optimizelegibility; color: rgb(0, 49, 60); font-family: &quot;Open Sans&quot;, sans-serif;">Rumen microbiota plays an important role in the evaluation of roughages. Gum Astragalus hay is a non-traditional roughage in ruminant feeding, and it is curious how it affects rumen microbiota of in comparison with AH. Aim. This study compares the in vitro true digestibility, rumen fermentation parameters, and the metagenomic profile of the bacterial community colonizing in the rumen of alfalfa hay (AH) and gum astragalus hay (Astragalus glycyphyllos, AG). Methods. The study carried out in vitro in Daisy incubator, a total of 100 samples, including 48 samples from each of the experimental roughages and 2 blind samples, were weighed into F57 bags for in vitro incubation. Rumen fluid was taken from the rumen of 2 sheep brought to the slaughterhouse from a private enterprise fed on roughage. Key results. Crude protein (CP) content of AG was higher (p&lt;0.0014) and ADF content (p&lt;0.001) was lower than AH. After 48 hours incubation of roughages samples, AG was superior to AH in terms of in vitro true digestibility parameters (IVTDROUGHAGE, IVTDDM, and IVTDOM) (p&lt;0.001). Taxonomy results at genus and species level of bacteria colonized in both roughage were obtained according to Shannon and Simpsons index. The bacterial community of the genus Provetalla was dominant in both forages, whereas Pseudomonas genus bacteria were observed in AG in contrast to AH. According to the total OTUs (Operational Taxonomc Unit) in the samples, it was observed that AH and AG had similarity as well as diversity in terms of species. Due to the current shortage of roughage, it is very important to consider AG as an alternative source of roughage in animal nutrition. Conclusions. The differences in nutrient composition between the two roughage types indicated differences in the composition and density of bacterial microbiota associated with these hays. These results were very important for improving the nutrient utilization efficiency of roughages in the desired direction. Implication. The nutrient composition and in vitro digestion parameter results of AG were comparable to AH, there were similarities as well as differences in the colonized bacterial community in both roughages. <div><br></div>