Probiotic characteristics and whole genome sequencing of Pediococcus pentosaceus SNF15 and its hold a protective effect on mice diarrhea induced by Escherichia coli K99

Yalan Su Mingque Feng Jingdi Tong Xiangfu Wen Meiyi Ren Deyuan Song Jinshang Song Xiaohan Li Qinna Xie Jia Cheng ^* Mingchao Liu ^*

• Hebei Agricultural University, Baoding, China

Diarrhea is one of the most common diseases of calves across the world, resulting in mortality and causing economic losses. Escherichia coli K99 is one of the primary pathogens that cause infectious diarrhea. Probiotics have been widely researched for their positive impact on inhibiting the growth of pathogenic bacteria and enhancing immunity and gut health as alternatives to antibiotics. This study isolated one probiotic from healthy calf feces: Pediococcus pentosaceus SNF15. Pediococcus pentosaceus SNF15 exhibited excellent growth performance and acid production capacity, resistance to bile salt and artificial gastroenteric fluid, and adherence to Caco-2 cells ability. Upon safety assessment, Pediococcus pentosaceus SNF15 was negative for hemolytic activity and sensitive to broad-spectrum antibiotics. We sequenced its whole genome to reveal the potential functional genes of Pediococcus pentosaceus SNF15. Several genes related to immune, anti-inflammatory, antagonistic pathogens, and carbohydrate utilization, including secondary bile acid, nicotinate and nicotinamide, were found in the genome of Pediococcus pentosaceus SNF15. The animal tests showed that the Pediococcus pentosaceus SNF15 treatment protects against E. coli K99 infection, as evidenced by clinical symptoms, including weight loss, fecal score, liver atrophy, and spleen enlargement occurred histological damage. Compared with the CN group, the supplementation of P. pentosaceus SNF15 strains ameliorated the damage of jejunum and the content of tight junction proteins occludin, claudin, ZO-1, and MUC2 and decreased the levels of IL-6, IL-1β, and TNF-α in jejunum. The 16S rDNA sequence results showed that infection with Escherichia coli K99 led to an imbalance in gut microbiota; the proportion of Firmicutes and Bacteroidetes decreased, and Proteobacteria increased. Pediococcus pentosaceus SNF15 helps improve intestinal microbial composition and prevents this trend. Pediococcus pentosaceus SNF15 supplementation can prevent and treat the clinical symptoms, intestinal epithelial mucosal integrity, intestinal permeability, and immune-related cytokines and regulate the intestinal microbiota in Escherichia coli K99-infected mice. This research revealed that Pediococcus pentosaceus SNF15 possesses desirable probiotic characteristics and could be used as a potential probiotic to remit neonatal calf diarrhea, caused by Escherichia coli K99 infection.