Chunjie Wang

To systematically investigate the metabolic and microbial differences in feed efficiency between Hereford × Simmental (H × S) crossbred and purebred Simmental cattle (S × S), 20 steers (initial weight = 268.80 ± 30.88 kg; initial age = 273.00 ± 14.09 days) were used, which were housed in mixed pens and fed a low-energy diet (0.75 Mcal Neg/kg DM). This study revealed that the level of Hypoglycin B was related to a reduced T3, which could affect growth performance. Metabolomics analysis identified Hypoglycin B, lysoPC, and DHAP as key discriminative metabolites. Pathway enrichment analysis revealed that these metabolites were primarily mapped to glycine, serine, and threonine metabolism; alanine, aspartate, and glutamate metabolism; and pantothenate and CoA biosynthesis. In our study, the relative abundances of Succinivibrio and Clostridium_sensu_stricto_6 were significantly greater in the H × S group than in the S × S group; it may have stronger energy extraction abilities and matches their lower F/G. Romboutsia was positively correlated with Hypoglycin B and negatively correlated with LysoPC (20:2 (11Z,14Z)/0:0), which might be related to changes in blood metabolites. Nevertheless, these explanations remain correlational and require functional validation through targeted interventions.

Background: The effects of Arula-7 powder (ASP) on diarrhea and intestinal barrier function associated with its regulation of intestinal microflora in calves infected with pathogenic Escherichia coli O₁ (E. coli O₁) were studied. Method: Twenty Holstein calves were randomly divided into four treatment groups: normal control (NC), model control (MC), 0.5 mg/kg ciprofloxacin (CIP) and 2.50 g/kg ASP groups. Results: ASP inhibited the relative abundance of Proteobacteria, Selenomonadales, and Enterobacteriales, and increased the relative abundance of Lactobacillus, Faecalibacterium, and Alloprevotella. Moreover, we demonstrated for the first time that the ASP and CIP promoted weight gain, reduced the diarrhea rate (P < 0.05), and enhanced antioxidant capacity (P < 0.05) due to the increase in average daily gain (ADG), total protein (TP), and albumin (ALB). In addition, ASP and CIP increased the expression of Zunola occludens-1 (ZO-1), Occludin, and Claudin-1 in the ileum (P < 0.05), and improved immunity due to increase levels of interleukin-2 (IL-2), interleukin-4 (IL-4), interferon-γ (IFN-γ), immunoglobulin A (IgA), and immunoglobulin G (IgG) in the serum, strengthened CD4⁺T levels in the ileal mucosa and reducing CD8⁺T and CD11c⁺T (P < 0.05). Conclusion: Hence, The intestinal microbiota environment formed by early intervention of ASP powder has a protective effect on the intestinal mucosal function of calves infected with pathogenic E. coli.

Lactobacillus paracaseifrom koumiss can enhance the integrity of intestinal mucosal barrier by changing intestinal flora and metabolites.

Introduction: Koumiss is a fermented horse milk food containing abundant probiotics. Lactobacillus paracasei is a bacterial strain isolated from koumiss that helps regulate the intestinal microbiota. One of the major cause of diarrhea is an imbalance of the intestinal flora. The aim of this study was to investigate whether Lactobacillus paracasei can ameliorate E. coli-induced diarrhea and modulate the gut microbiota.Methods: Mouse models of diarrhea were established via intragastric E. coli O₈ administration. We then attempted to prevent or treat diarrhea in the mice via intragastric administration of a 3 × 10⁸ CFU/mL L. paracasei cell suspension. The severity of diarrhea was evaluated based on the body weight, diarrhea rate, and index, fecal diameter, ileum injury, hematoxylin-eosin (H&E) staining, and diamine oxidase (DAO) and zonulin expression. Expression of the tight junction (TJ) proteins claudin-1, occludin, and zona occludens (ZO-)1 were detected by immunohistochemistry (IHC). Gastrointestinal mRNA expression levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α were detected by real-time polymerase chain reaction (RT-PCR). The microbial composition was analyzed by 16s rRNA sequencing.Results: The L. paracasei demonstrated excellent therapeutic efficacy against diarrhea. It elevated the TJ protein levels and downregulated proinflammatory cytokines IL-6, IL-1β, TNF-α, and p65, myosin light chain 2 (MLC2), myosin light chain kinase (MLCK). Moreover L. paracasei increased those bacteria, which can product short-chain fatty acid (SCFA) such Alistipes, Odoribacter, Roseburia, and Oscillibacter.Conclusion: L. paracasei ameliorated diarrhea by inhibiting activation of the nuclear factor kappa B (NF-κB)-MLCK pathway and increasing the abundance of gut microbiota that produce SCFA.

The diet energy level plays a vital role in the energy balance of transition cows. We investigated the effects of high dietary energy density on body metabolism. Twenty multiparous Angus cows were randomly assigned to two treatment groups (10 cows/treatment), one receiving a high-energy (HE) diet (NEm = 1.67 Mcal/kg of DM) and the other administered a control (CON) diet (NEm = 1.53 Mcal/kg of DM). The results indicated that feeding a high-energy diet resulted in higher plasma glucose concentration and lower concentrations of plasma NEFA and BHBA on d 14 relative to calving in the HE-fed cows compared to the CON-fed ones. The postpartum plasma levels of T-AOC were lower in cows that received the CON diet than in cows in the HE group, while the concentration of malondialdehyde (MDA) showed an opposite trend. Among the 51 significantly different metabolites, the concentrations of most identified fatty acids decreased in HE cows. The concentrations of inosine, glutamine, and citric acid were higher in HE-fed cows than in CON-fed cows. Enrichment analysis revealed that linoleic acid metabolism, valine, leucine as well as isoleucine biosynthesis, and glycerophospholipid metabolism were significantly enriched in the two groups.

Calf diarrhea caused by pathogenic Escherichia coli is a major cause of death in calves, with a mortality rate of over 50%. It is crucial to understand the pathogenesis and development of calf diarrhea for its prevention and treatment. We aimed to study the effect of pathogenic E. coli on the flora composition, function, and short-chain fatty acid (SCFA) content of calf feces using a calf diarrhea model. Sixty-four newborn Holstein calves (40–43 kg) were divided into a normal group (NG; n = 32) and a test group (TG; n = 32). At the beginning of the experiment, the TG were orally administered pathogenic E. coli O1 (2.5 × 10¹¹ CFU/mL, 100 mL) to establish a calf diarrhea model, and the NG were orally administered the same amount of physiological saline solution. The calves of the two groups were subjected to the same feeding and management. Fresh feces samples were collected at different time points and subjected to 16S rRNA high-throughput sequencing and gas chromatography–mass spectrometry to determine the fecal microbial composition and SCFA content. Pathogenic E. coli O1 significantly altered microbiotas composition in the feces of calves, increasing the relative abundance of Proteobacteria and decreasing that of Firmicutes. It also led to a significant increase in the relative abundance of Escherichia-Shigella and a decrease in Lactobacillus, as well as significantly decreased SCFA content. Therefore, we postulate that pathogenic E. coli induces calf diarrhea by causing intestinal florae imbalance and reducing the content of SCFA.

We evaluated the effects of probiotic compounds on the composition of the gut microbiota. Forty newborn calves were random allocated to the lactic acid bacteria + yeast group (LS group), lactic acid bacteria group (L group), yeast group (S group), and control group (D group). Probiotics containing Lactococcus lactis subsp. lactis, Pediococcus pentosaceus, Lactobacillus plantarum, Saccharomyces cerevisiae, and Kluyveromyces marxianus were fed to calves in the three treatment groups for 15 days. The feeding process lasted 15 days. Fecal samples were collected from all calves at the end of the trial and analyzed using high-throughput 16S rRNA sequencing. Totals of 1,029,260 high-quality reads and 420,010,128 bp of sequences were obtained. Among the four groups, the alpha diversity of gut microbes was significantly higher in newborn cattle in the LS group than in those in the L, S, and D groups. Overall, the dominant phyla were Firmicutes, Actinobacteria, and Bacteroidetes, whereas Bifidobacterium was the most abundant phylum in the gut of cattle in the LS group. Newborn calves from the compound probiotic groups had closely clustered gut bacterial communities and had lower rates of diarrhea. Overall, compound probiotics regulated the intestinal microbiota community structure of newborn calves and improved intestinal health. New information relevant to the prevention of diarrhea is provided by our research in newborn calves.