The aim of this study was to explore the association between antimicrobial resistance, ESBL genes, and virulence genes of Salmonella isolates. From 2019 to 2021, a total of 117 Salmonella isolates were obtained from symptomatic chickens in Sichuan Province, China. The strains were tested for antimicrobial resistance and the presence of ESBL according to the Clinical and Laboratory Standards Institute (CLSI) instructions. The presence of ESBL genes and genes for virulence was determined using Polymerase Chain Reaction (PCR). In addition, Multilocus Sequence Typing (MLST) was applied to confirm the molecular genotyping. Moreover, the mechanism of ESBL and virulence gene transfer and the relationships between the resistance phenotype, ESBL genes, and virulence genes were explored. The isolates exhibited different frequencies of resistance to antibiotics (resistance rates ranged from 21.37% to 97.44%), whereas 68.38% and 41.03% of isolates were multi-drug resistance (MDR) and ESBL-producers, respectively. In the PCR analysis, bla_CTX-M was the most prevalent ESBL genotype (73.42%, 58/79), and bla_CTX-M-55 showed the most significant effect on the resistance to cephalosporins as tested by logistic regression analysis. Isolates showed a high carriage rate of invA, avrA, sopB, sopE, ssaQ, spvR, spvB, spvC, stn, and bcfC (ranged from 51.28% to 100%). MLST analysis revealed that the 117 isolates were divided into 11 types, mainly ST92, ST11, and ST3717. Of 48 ESBL-producers, 21 transconjugants were successfully obtained by conjugation. Furthermore, ESBL and spv virulence genes were obtained simultaneously in 15 transconjugants. These results highlighted that Salmonella isolates were common carriers of ESBLs and multiple virulence genes. Horizontal transfer played a key role in disseminating antimicrobial resistance and pathogenesis. Therefore, it is necessary to continuously monitor the use of antimicrobials and the prevalence of AMR and virulence in Salmonella from food animals and to improve the antibiotic stewardship for salmonellosis.

Lipopolysaccharide (LPS) has been considered the primary agent to establish animal models of inflammation, immunological stress, and organ injury. Previous studies have demonstrated that LPS impaired gastrointestinal development and disrupted intestinal microbial composition and metabolism. Ferulic acid (FA) isolated from multiple plants exhibits multiple biological activities. This study investigated whether FA ameliorated intestinal function and microflora in LPS-challenged Tianfu broilers. The results showed that LPS challenge impaired intestinal function, as evidenced by decreased antioxidant functions (p < 0.05), disrupted morphological structure (p < 0.05), and increased intestinal permeability (p < 0.05); however, these adverse effects were improved by FA supplementation. Additionally, FA supplementation preserved sIgA levels (p < 0.05), increased mRNA expression levels of CLDN and ZO-1 (p < 0.05), and enhanced epithelial proliferation (p < 0.05) in the ileal mucosa in LPS-challenged chickens. Moreover, FA supplementation rectified the ileal microflora disturbances in the LPS-challenged broilers. The results demonstrate that dietary FA supplementation decreased LPS-induced intestinal damage by enhancing antioxidant capacity and maintaining intestinal integrity. Furthermore, FA supplementation protects intestinal tight junctions (TJs), elevates secretory immunoglobulin A (sIgA) levels, and modulates ileal microflora composition in LPS-challenged broilers.

The excessive intake of fluoride, one of the trace elements required to maintain health, leads to liver injury. Tetramethylpyrazine (TMP) is a kind of traditional Chinese medicine monomer with a good antioxidant and hepatoprotective function. The aim of this study was to investigate the effect of TMP on liver injury induced by acute fluorosis. A total of 60 1-month-old male ICR mice were selected. All mice were randomly divided into five groups: a control (K) group, a model (F) group, a low-dose (LT) group, a medium-dose (MT) group, and a high-dose (HT) group. The control and model groups were given distilled water, while 40 mg/kg (LT), 80 mg/kg (MT), or 160 mg/kg (HT) of TMP was fed by gavage for two weeks, with a maximum gavage volume for the mice of 0.2 mL/10 g/d. Except for the control group, all groups were given fluoride (35 mg/kg) by an intraperitoneal injection on the last day of the experiment. The results of this study showed that, compared with the model group, TMP alleviated the pathological changes in the liver induced by the fluoride and improved the ultrastructure of liver cells; TMP significantly decreased the levels of ALT, AST, and MDA (p < 0.05) and increased the levels of T-AOC, T-SOD, and GSH (p < 0.05). The results of mRNA detection showed that TMP significantly increased the mRNA expression levels of Nrf2, HO-1, CAT, GSH-Px, and SOD in the liver compared with the model group (p < 0.05). In conclusion, TMP can inhibit oxidative stress by activating the Nrf2 pathway and alleviate the liver injury induced by fluoride.

Excessive intake of fluoride, one of the trace elements to maintain health, leads to liver injury. Tetramethylpyrazine (TMP) is a kind of traditional Chinese medicine monomer with good antioxidant and hepatoprotective function. The aim of this study was to investigate the effect of TMP on liver injury induced by acute fluorosis. A total of 60 1-month-old male Institute of Cancer Research mice without carriage of pathogenic bacteria were selected. All mice were fed adaptively for one week, and then randomly divided into 5 groups: control (K) group, model (F) group, low-dose (LT) group, medium-dose (MT) group and high-dose (HT) group. The control and model group were given distilled water, while 40 mg/kg (LT), 80 mg/kg (MT) and 160 mg/kg (HT) TMP were fed by gavage for two weeks with the maximum gavage volume of mice is 0.2ml/10g/d. Except for the control group, all groups were given fluoride (35 mg/kg) by intraperitoneal injection on the last day of the experiment. The results of this study showed that compared with the model group, TMP alleviated the pathological changes of liver induced by fluoride and improved the ultrastructure of liver cells; TMP significantly decreased the levels of ALT, AST and MDA (P <0.05), and increased the levels of T-AOC, T-SOD and GSH (P <0.05). The results of mRNA detection showed that TMP significantly increased the mRNA expression levels of Nrf2, HO-1, CAT, GSH-Px and SOD in liver compared with model group (P <0.05). In conclusion, TMP can inhibit oxidative stress by activating Nrf2 pathway and alleviate liver injury induced by fluoride.