AUTHOR=Ma Peng , Sun Chaoqun , Liu Minze , You Hongnan , Shen Yao , Kang Yajie , Sun Yuqin , Yang Zhengang , Ma Pengyun , Yang Liang , Xue Fuguang 

TITLE=Metagenomic insights into the rumen epithelial integrity responses to the vitamin B1 supplement under high-concentrate diets treatments

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1008373

DOI=10.3389/fmicb.2022.1008373

ISSN=1664-302X

ABSTRACT=Subacute ruminal acidosis (SARA) becomes the most common nutritional metabolic disease in high yielding dairy cows and latter fatting beef cattle because of the increasing consumption of high-concentrate diets in the modern feeding patterns. Our previous research found a certain of evidences that adding 180 mg thiamine/kg DMI could increase the rumen pH and regulate the structure of rumen microbial community in vivo. However, there is still limited experimental data on the effects of SARA on thiamine status, the damage on the structure of rumen epithelial cells and the underlying mechanism on the epithelium alterations. For this purpose, a total of 18 Angus bulls (average 22.0-months-old) with the average live weight of 567.6±27.4kg were randomly allocated into the control treatment (CON), the high concentrate diet treatment (HC) and the high concentrate diet with vitamin B1 supplement treatment (HCB). All bulls were conducted with a 7-day adjustment period followed by a 60-day-long main feeding procedure. Results indicated that, ADFI and ADG significantly decreased in HC treatment compared with CON (P<0.05), while significantly increased after VB1 supplement (P<0.05). Besides, ruminal acetate content was significantly down-regulated while the propionate significant up-regulated under HC treatment compared with CON (P<0.05), however, these alterations showed a completely inverse regulatory effect after VB1 supplement compared with HC (P<0.05). These changes causatively induced a significant decrease of A/P ratio in HC treatment compared with CON and HCB treatments (P<0.05). Bacterial communities in HC treatment could be clearly separated from those in CON through PCoA axes 1 and 2. Meanwhile, VB1 supplement significantly altered the bacterial communities compared with HC treatment, except HCB-3. Furthermore, HC treatment significantly up-regulated the expression of JNK, Bax, Caspase-8, Caspase-3, Caspase-9, and Cyt-C compared with CON, while significant down-regulated the expression of Bcl-2. VB1 supplement showed the complete converse gene expression compared with HC. In conclusion, VB1 supplement could effectively attenuate the alterations occurred when exposed to high-concentrate diets, and help promoted the production performances through increase fermentability.