Florfenicol induces oxidative stress and hepatocyte apoptosis in broilers via Nrf2 pathway

A review on the antibiotic florfenicol: Occurrence, environmental fate, effects, and health risks

Florfenicol, as a replacement for chloramphenicol, can tightly bind to the A site of the 23S rRNA in the 50S subunit of the 70S ribosome, thereby inhibiting protein synthesis and bacterial proliferation. Due to the widespread use in aquaculture and veterinary medicine, florfenicol has been detected in the aquatic environment worldwide. Concerns over the effects and health risks of florfenicol on target and non-target organisms have been raised in recent years. Although the ecotoxicity of florfenicol has been widely reported in different species, no attempt has been made to review the current research progress of florfenicol toxicity, hormesis, and its health risks posed to biota. In this study, a comprehensive literature review was conducted to summarize the effects of florfenicol on various organisms including bacteria, algae, invertebrates, fishes, birds, and mammals. The generation of antibiotic resistant bacteria and spread antibiotic resistant genes, closely associated with hormesis, are pressing environmental health issues stemming from overuse or misuse of antibiotics including florfenicol. Exposure to florfenicol at μg/L-mg/L induced hormetic effects in several algal species, and chromoplasts might serve as a target for florfenicol-induced effects; however, the underlying molecular mechanisms are completely lacking. Exposure to high levels (mg/L) of florfenicol modified the xenobiotic metabolism, antioxidant systems, and energy metabolism, resulting in hepatotoxicity, renal toxicity, immunotoxicity, developmental toxicity, reproductive toxicity, obesogenic effects, and hormesis in different animal species. Mitochondria and the associated energy metabolism are suggested to be the primary targets for florfenicol toxicity in animals, albeit further in-depth investigations are warranted for revealing the long-term effects (e.g., whole-life-cycle impacts, multigenerational effects) of florfenicol, especially at environmental levels, and the underlying mechanisms. This will facilitate the evaluation of potential hormetic effects and construction of adverse outcome pathways for environmental risk assessment and regulation of florfenicol.

Effects of dietary supplementation of cumin (Cuminum cyminum L.) essential oil on expression of genes related to antioxidant, apoptosis, detoxification, and heat shock mechanism in heat-stressed broiler chickens

This study was carried out to evaluate the impact of cumin essential oil (CEO) supplementation on levels of certain gene expression related to antioxidant, apoptotic, detoxific, and heat shock mechanisms in the breast meat and ileum of heat-stressed broilers. The study was conducted on a 2 × 6 factorial design (heat stress + feed additive) on 600 day-old male broiler chicks for a period of 42 days. From day 7 to 42, although broilers in heat stress groups (HT) were exposed to constant chronic heat stress (36 °C), others were housed at thermoneutral ambient temperature (TN). The chicks in both conditions were fed with 6 experimental diets: C0 (basal diet with no additive), ANTIB (basal diet + 100 mg/kg chloramphenicol), VITE (basal diet + 50 IU α-tocopherol), C2 (basal diet + 200 mg/kg CEO), C4 (basal diet + 400 mg/kg CEO), C6 (basal diet+ 600 mg/kg CEO). The results showed that heat stress upregulated (except for Bcl-2) the genes related to antioxidant, apoptosis, detoxification, and heat shock mechanism. However, cumin essential oil increased the dose-dependently positive effect on certain genes in tissues of the heat-stressed broilers and downregulated (except for Bcl-2) these genes.

Aflatoxin B1 triggers apoptosis in rabbit hepatocytes via mediating oxidative stress and switching on the mitochondrial apoptosis pathway

Aflatoxin B1 (AFB1) is considered the most toxic carcinogenic compound, and exposure to AFB1 is highly associated with hepatocellular carcinoma. The aim of this study was to investigate the effects of different doses of AFB1 on growth performance and the liver of rabbits, as well as explore its underlying mechanisms. A total of eighty 30-day-old meat rabbits were randomly divided into four treatments. The control group was fed a pollution-free diet, while the AFL, AFM, and AFH groups were fed contaminated diets containing 13 μg/kg, 19 μg/kg, and 25 μg/kg of AFB1, respectively. The results showed that AFB1 had detrimental effects on the production performance of rabbits, resulting in decreased weight gain. Additionally, AFB1 exposure was associated with increased activity of Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT), as well as decreased levels of total protein (TP) and albumin (ALB) in the serum. AFB1 induced the production of reactive oxygen species (ROS) and malondialdehyde (MDA) while inhibiting the activity of glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) activity in liver tissues. AFB1 decreased the mRNA transcription and protein expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NAD(P)H dehydrogenase quinone-1 (NQO-1). AFB1 not only decreased the contents of cytochrome P4501A2 (CYP1A2), cytochrome P4502A6 (CYP2A6) and cytochrome P4503A4 (CYP3A4) but also increased the content of AFB1-DNA adducts in the liver. Furthermore, AFB1 enhanced the expression of cytochrome c (cyt-c), caspase-9, caspase-3, and Bcl-2-associated X protein (Bax), while inhibiting the expression of B-cell lymphoma 2 (Bcl-2). Therefore, we demonstrated that AFB1 triggered apoptosis in rabbit hepatocytes via mediating oxidative stress and switching on the mitochondrial apoptosis pathway, and decreased rabbit performance.

Recent developments in Salvia miltiorrhiza polysaccharides: Isolation, purification, structural characteristics and biological activities

In recent years, natural polysaccharides have attracted more and more attention and research because of their value in the medicine, beauty and food fields. Salvia miltiorrhiza is a traditional Chinese herb that has been used for thousands of years and has antidiabetic, antifibrotic, neuroprotective, antioxidation, anti-inflammatory and other effects. It mainly includes rosmarinic acid, tanshinone I, tanshinone IIA, tanshinone IIB, procatechualdehyde, polysaccharide and salvianolic acids. Salvia miltiorrhiza polysaccharide is a polysaccharide extracted and isolated from Salvia miltiorrhiza and has diverse biological functions, including antioxidation, anti-tumor, hepatoprotective, anti-inflammatory, immune regulatory and cardioprotective effect. In this review, the extraction, purification, structural characterization and biological activity of SMPs are summarized and new perspectives for the future work of SMPs were also proposed, we hope our research can provide a reference for further research on SMPs.

Salvia miltiorrhiza polysaccharides alleviate florfenicol-induced inflammation and oxidative stress in chick livers by regulating phagosome signaling pathway

Florfenicol (FFC) is a commonly used antibiotic in animal breeding, especially in broiler breeding. Previous studies found that FFC could affect the liver function of chickens. However, the mechanisms underlying the effects of FFC on liver function are still not completely clear. Moreover, the research on drugs that antagonize FFC hepatotoxicity is relatively lacking. Salvia miltiorrhiza polysaccharides (SMPs) have been proved to have obvious liver protection effects. Therefore, we exposed chicks to FFC at the clinically recommended dose of 0.15 g/L. At the same time, 0.15 g/L FFC and 5 g/L SMPs were given to another group of chicks. After 5 days of continuous administration, the livers of chicks from different treatment groups were sequenced by transcriptome and proteome. Based on the analysis of sequencing data, we also focused on the detection of inflammation and oxidation indicators related to the phagosome signaling pathway with significant enrichment of differential factors in the livers of chicks. The results showed that some significantly differentially expressed genes and proteins induced by FFC were enriched in the phagosome signaling pathway, and they increased the expression levels of inflammatory factors and peroxides. However, SMPs intervention significantly reversed the tendency of FFC to alter phagosome signaling pathways and reduced the expression levels of inflammatory factors and peroxides. In conclusion, FFC caused liver inflammation and oxidative stress in chicks by regulating the phagosome signaling pathway. Meanwhile, SMPs could improve the adverse effects of FFC on the phagosome signaling pathway. This study provided new insights into the ameliorative effects and mechanisms of SMPs on hepatotoxicity of FFC.

The Berberis vulgaris L. extract berberine exerts its anti-oxidant effects to ameliorate cholesterol overloading-induced cell apoptosis in the primary mice hepatocytes: an in vitro study

Cholesterol overloading stress damages normal cellular functions in hepatocytes and induces metabolic disorders to facilitate the development of multiple diseases, including cardiovascular diseases, which seriously degrades the life quality of human beings. Recent data suggest that the Berberis vulgaris L. extract berberine is capable of regulating cholesterol homeostasis, which is deemed as potential therapeutic drug for the treatment of cholesterol overloading-associated diseases, but its detailed functions and molecular mechanisms are still largely unknown. In the present study, we evidenced that berberine suppressed cell apoptosis in high-cholesterol-diet mice liver and cholesterol-overloaded mice hepatocytes. Also, cholesterol overloading promoted reactive oxygen species (ROS) generation to trigger oxidative damages in hepatocytes, which were reversed by co-treating cells with both berberine and the ROS scavenger N-acetylcysteine (NAC). Moreover, the underlying mechanisms were uncovered, and we validated that berberine downregulated Keap1, and upregulated Nrf2 to activate the anti-oxidant Nrf2/HO-1 signaling pathway in cholesterol overloading-treated hepatocytes, and both Keap1 upregulation and Nrf2 downregulation abrogated the suppressing effects of berberine on cell apoptosis in the hepatocytes with cholesterol exposure. Taken together, we concluded that berberine activated the anti-oxidant Keap1/Nrf2/HO-1 pathway to eliminate cholesterol overloading-induced oxidative stress and apoptotic cell death in mice hepatocytes, and those evidences hinted that berberine might be used as putative therapeutic drug for the treatment of cholesterol overloading-associated cardiovascular diseases.

Urinary concentrations of amphenicol antibiotics in relation to biomarkers of oxidative DNA and RNA damage in school children

Previous studies implied that elevated exposure to amphenicol antibiotics may induce increased oxidative stress. However, the effects of amphenicol antibiotics exposure on oxidative stress damage in human have not been well studied. This study examined the associations between amphenicol antibiotics exposure and oxidative damage biomarkers in school children. Three major amphenicols including chloramphenicol (CAP), thiamphenicol (TAP), florfenicol (FF) and two biomarkers of 8-hydroxydeoxyguanosine (8-OHdG) for oxidative DNA damage and 8-oxo-7,8- dihydroguanosine (8-OHG) for oxidative RNA damage were measured in 414 morning urine samples collected from 70 school children in Shanghai, China. School children were exposed to CAP, TAP, and FF with median concentrations of 1.37, 0.36, and 0.06 μg/g Cre, respectively. Linear mixed models revealed that an interquartile range (IQR) increase of urinary TAP was positively associated with 7.75%(95% CI: 4.40%, 11.1%) increase of 8-OHdG and 7.48%(95% CI: 2.49%, 15.6%) increase of 8-OHG, respectively; in addition, CAP was associated with elevated 8-OHdG. Although FF was not found to be significantly associated with either 8-OHdG or 8-OHG, it is warranted to further investigate FF and its metabolites levels in relation to oxidative stress in future study. Our findings provide new evidence for the effects of exposure to TAP and CAP on nucleic acid oxidative damage in Children.

Study on the mechanism of Salvia miltiorrhiza polysaccharides in relieving liver injury of broilers induced by florfenicol

In order to explore the transcriptomics and proteomics targets and pathways of Salvia miltiorrhiza polysaccharides (SMPs) alleviating florfenicol (FFC)-induced liver injury in broilers, 60 1-day-old broilers were randomly divided into 3 groups: control group ( GP1) was fed tap water, FFC model (GP2) was given tap water containing FFC 0.15 g/L, and SMPs treatment group (GP3) was given tap water containing FFC 0.15 g/L and SMPs 5 g/L. Starting from 1 day of age, the drug was administered continuously for 5 days. On the 6th day, blood was collected from the heart and the liver was taken. Then 3 chickens were randomly taken from each group, and their liver tissues were aseptically removed and placed in an enzyme-free tube. Using high-throughput mRNA sequencing and TMT-labeled quantitative proteomics technology, the transcriptome and proteome of the three groups of broiler liver were analyzed, respectively. The results of the study showed that the liver tissue morphology of the chicks in the GP1 and GP3 groups was complete and there were no obvious necrotic cells in the liver cells. The liver tissue cells in the GP2 group showed obvious damage, the intercellular space increased, and the liver cells showed extensive vacuolation and steatosis. Compared with the GP1 group, the daily gain of chicks in the GP2 group was significantly reduced (P < 0.0 5 or P < 0.01). Compared with the GP2 group, the GP3 group significantly increased the daily gain of chicks (P <0.0 5 or P <0.01). Compared with the GP1 group, the serum levels of ALT, AST, liver LPO, ROS, and IL-6 in the GP2 group were significantly increased (P < 0.0 5 or P < 0.01), and the contents of T-AOC, GSH-PX, IL-4, and IL-10 in the liver were significantly decreased (P < 0.0 5 or P < 0.01). After SMPs treatment, the serum levels of ALT, AST, liver LPO, ROS, and IL-6 were significantly reduced (P < 0.0 5 or P < 0.01), and the contents of T-AOC, GSH-PX, IL-4, and IL-10 in the liver were significantly increased (P < 0.0 5 or P < 0.01). There were 380 mRNA and 178 protein differentially expressed between GP2 group and GP3 group. Part of DEGs was randomly selected for QPCR verification, and the expression results of randomly selected FABP1, SLC16A1, GPT2, AACS, and other genes were verified by QPCR to be consistent with the sequencing results, which demonstrated the accuracy of transcriptation-associated proteomics sequencing. The results showed that SMPs could alleviate the oxidative stress and inflammatory damage caused by FFC in the liver of chicken and restore the normal function of the liver. SMPs may alleviate the liver damage caused by FFC by regulating the drug metabolism-cytochrome P450, PPAR signaling pathway, MAPK signaling pathway, glutathione metabolism, and other pathways.

Maximum levels of cross-contamination for 24 antimicrobial active substances in non-target feed. Part 7: Amphenicols: florfenicol and thiamphenicol

The specific concentrations of florfenicol and thiamphenicol in non-target feed for food-producing animals, below which there would not be an effect on the emergence of, and/or selection for, resistance in bacteria relevant for human and animal health, as well as the specific antimicrobial concentrations in feed which have an effect in terms of growth promotion/increased yield, were assessed by EFSA in collaboration with EMA. Details of the methodology used for this assessment, associated data gaps and uncertainties, are presented in a separate document. To address antimicrobial resistance, the Feed Antimicrobial Resistance Selection Concentration (FARSC) model developed specifically for the assessment was applied. The FARSC for florfenicol was estimated. However, due to the lack of data, the calculation of the FARSC for thiamphenicol was not possible until further experimental data become available. To address growth promotion, data from scientific publications obtained from an extensive literature review were used. Levels in feed that showed to have an effect on growth promotion/increased yield were reported for florfenicol, whilst for thiamphenicol no suitable data for the assessment were available. Uncertainties and data gaps associated to the levels reported were addressed. For florfenicol, it was recommended to perform further studies to supply more diverse and complete data related to the requirements for calculation of the FARSC, whereas for thiamphenicol, the recommendation was to generate the data required to fill the gaps which prevented the FARSC calculation.

Proteome and transcriptome analysis revealed florfenicol via affected drug metabolism and lipid metabolism induce liver injury of broilers

In order to explore the mechanism of liver injury induced by florfenicol (FFC) in broilers. Sixty broilers were randomly divided into 2 groups: control group: normal drinking water and feed were given every d; FFC group: tap water containing FFC (0.15g/L) was given every d and feed was taken freely; each group was given 5 dd of continuous medication and feed was taken freely. The results showed that compared with the control group, FFC could significantly inhibit the weight gain of broilers (P < 0.05), and significantly inhibit the expression of CYP1A1 and CYP2H1 in liver tissue (P < 0.05). It was found that the expression of genes related to the effect of cytochrome P450 on the metabolism of exogenous substances, the peroxisome proliferators-activated receptors signal pathway, peroxisome pathway and glutathione metabolic pathway in the liver of broilers. The results of qPCR of UDP glucuronosyltransferase family 2A1 (UGT2A1), glutathione S-transferase-like 2 (GSTAL2), hematopoietic prostaglandin D synthase (HPGDS), glutathione S-transferase theta 1(GSTT1), isocitrate dehydrogenase (NADP(+)) 1 (IDH1), acyl-CoA oxidase 2 (ACOX2), fatty acid binding protein 1 (FABP1), adenylosuccinate lyase (ADSL), and phosphoribosyl aminoim idazolesuccino carboxamide synthase (PAICS) genes which were randomly selected from the most significant genes were consistent with those of RNA-seq. The results showed that FFC can affect the drug metabolism and lipid synthesis in the liver of broiler, thus impairing the normal function of liver and the growth and development of broiler.

Florfenicol induces renal toxicity in chicks by promoting oxidative stress and apoptosis

To explore the mechanism of renal toxicity induced by florfenicol (FFC), 120 chicks were randomly divided into 6 groups, 20 in each group. Except for the control group, different doses of FFC (0.15 g/L, 0.3 g/L, 0.6 g/L, 1.2 g/L, and 1.8 g/L) were added to drinking water in the other 5 groups. Five days later, blood was collected from the vein under the wing, and the complete kidneys were obtained as soon as possible, then tested the experimental indicators. The results showed that compared with control group, all doses of FFC significantly reduced the average weight gain of chicks (P < 0.05 or P < 0.01). Except for the 0.15 g/L FFC group, kidney index of chicks in the other doses of FFC groups were significantly increased (P < 0.05 or P < 0.01). The kidney tissues in all FFC groups showed obvious damage, deformities, cell atrophy, and cell gap enlargement. In addition, all doses of FFC significantly increased the contents of uric acid (UA), blood urea nitrogen (BUN), creatinine (CRE) in serum, and malondialdehyde (MDA) in renal tissue (P < 0.05 or P < 0.01), but significantly reduced the levels of glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) in renal tissue (P < 0.05 or P < 0.01). FFC significantly inhibited the mRNA and protein expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and nicotinamide adenine dinucleotide phosphate: quinone oxidoreductase-1 (NQO-1), and increased the mRNA and protein expression levels of p53, Caspase-3, and Caspase-6 (P < 0.05 or P < 0.01). The apoptotic rate of renal cells in all doses of FFC groups increased significantly (P < 0.05 or P < 0.01). It was concluded that FFC had a certain degree of nephrotoxicity, and with the increase of FFC concentration, the kidney injury of chicks became more and more serious. FFC promoted oxidative stress response in kidney of chicks by inhibiting the expression of related factors in Nrf2-ARE pathway. Moreover, the expression of pro-apoptotic factors was upregulated to improve the apoptosis rate of renal cells, which resulted in excessive apoptosis of renal cells and seriously affected the kidney function of chicks.

Hydrogen peroxide-induced oxidative stress impairs redox status and damages aerobic metabolism of breast muscle in broilers

Oxidative stress has always been a hot topic in poultry science. However, studies concerning the effects of redox status and glucose metabolism induced by hydrogen peroxide (H₂O₂) in the breast muscle of broilers have been rarely reported. This study was aimed to evaluate the impact of intraperitoneal injection of H₂O₂ on oxidative damage and glycolysis metabolism of breast muscle in broilers. We also explored the activation of the nuclear factor erythroid 2–related factor 2 (Nrf2) signaling pathway to provide possible mechanism of the redox imbalance. Briefly, a total of 320 one-day-old Arbor Acres chicks were randomly divided into 5 treatments with 8 replicates of 8 birds each (noninjected control, 0.75% saline-injected, 2.5, 5.0, and 10.0% H₂O₂-injected treatments). Saline group was intraperitoneally injected with physiological saline (0.75%) and H₂O₂ groups received an intraperitoneal injection of H₂O_2. The dosage of the injection was 1.0 mL/kg BW. All birds in the saline and H₂O₂ groups were injected on days 16 and 37 of the experimental period. At 42 d of age, 40 birds (8 cages per group and one chicken per cage) were selected to be stunned electrically (50 V, alternating current, 400 Hz for 5 s each one), and then immediately slaughtered via exsanguination. The results showed that broilers in the H₂O₂ injection group linearly exhibited higher contents of reactive oxygen species, carbonyl and malondialdehyde, and lower total antioxidant capacity and glutathione peroxidase activities. With the content of H₂O₂ increased, the H₂O₂ groups linearly downregulated the mRNA expressions of GPX, CAT, HMOX1, NQO1, and Nrf2 and its downstream target genes. In addition, H₂O₂ increased serum activities of creatine kinase and lactate dehydrogenase. Meanwhile, in the pectoral muscle, the glycogen content was linearly decreased, and the lactate content was linearly increased in muscle of broilers injected with H₂O₂. In addition, the activities of glycolytic enzymes including pyruvate kinase, hexokinase, and lactate dehydrogenase were linearly increased after exposure to H₂O₂. In conclusion, H₂O₂ injection could impair antioxidant status and enhance anaerobic metabolism of breast muscle in broilers.